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Yasuo Ando

Section

Graduate School of Engineering

Job title

Professor

Degree

博士（工学）（東北大学）

researchmap

https://researchmap.jp/yasuoando

J-GLOBAL ID

200901031635072599

Research History 1

1986/04 - 1992/11

コニカ株式会社　研究員

Education 2

Tohoku University　Graduate School, Division of Engineering　応用物理学

- 1986/03/25
Tohoku University　Faculty of Engineering　応用物理学科

- 1984/03/25

Committee Memberships 50

日本学術振興会　産学協力研究委員会147委員会委員

2018/12 - Present
公益財団法人コニカミノルタ科学技術振興財団　奨励賞審査委員

2014/01 - Present
応用物理学会　東北支部幹事

2014/01 - Present
応用物理学会　スピンエレクトロニクス研究会幹事

2012/01 - Present
応用物理学会　評議委員

2011/03 - Present
応用物理学会スピントロニクス研究会　委員長

2011/01 - Present
スピントロニクス不揮発性機能技術調査委員会　委員

2008/05 - Present
スピントロニクス不揮発性機能技術調査委員会　委員

2008/05 - Present
高機能・超低消費電力スピンデバイス・ストレージ基盤技術の開発プロジェクト　推進委員

2007/10 - Present
高機能・超低消費電力スピンデバイス・ストレージ基盤技術の開発プロジェクト　推進委員

2007/10 - Present
ISAMMA 2007　Program Committee

2007/06 - Present
ISAMMA 2007　プログラム委員会

2007/06 - Present
応用物理学会東北支部　幹事

2007/04 - Present
応用物理学会東北支部　幹事

2007/04 - Present
応用物理学会スピンエレクトロニクス研究会　幹事

2006/01 - Present
応用物理学会　論文賞審査委員

2017 - 2018
日本学術振興会　学術システム研究センター研究員

2013/04 - 2016/03
応用物理学会　業績賞委員会委員

2015 - 2016
応用物理学会　東北支部長

2012/01 - 2013/12
応用物理学会　評議委員

2011/03 - 2013/03
応用物理学会スピントロニクス研究会　委員長

2011/01 - 2012/12
応用物理学会　2011年秋季学術講演会現地実行委員

2010/08 - 2011/08
応用物理学会　2011年秋季学術講演会現地実行委員

2010/08 - 2011/08
ISAMMA 2010　Executive Committee

2009/04 - 2011/03
ISAMMA 2010　Executive Committee

2009/04 - 2011/03
応用物理学会　理事

2009/03 - 2011/03
応用物理学会　理事

2009/03 - 2011/03
応用物理学会スピンエレクトロニクス研究会　幹事

2006/01 - 2010/12
日本磁気学会論文賞，学術奨励賞選考委員会　委員

2008/04 - 2010/03
日本磁気学会論文賞，学術奨励賞選考委員会　委員

2008/04 - 2010/03
新機能トランジスタ調査委員会　副委員長

2007/06 - 2010/03
新機能トランジスタ調査委員会　副委員長

2007/06 - 2010/03
特別研究員等審査会　審査委員

2006/08 - 2007/07
特別研究員等審査会　審査委員

2006/08 - 2007/07
応用物理学会　代議員

2002/02 - 2006/01
応用物理学会　代議員

2002/02 - 2006/01
応用物理学会スピンエレクトロニクス研究会　庶務幹事

2003/01 - 2004/12
応用物理学会スピンエレクトロニクス研究会　庶務幹事

2003/01 - 2004/12
応用物理学会東北支部　庶務幹事

2000/01 - 2001/12
応用物理学会東北支部　庶務幹事

2000/01 - 2001/12
International Symposium on Nanoscale Magnetism and Transport　現地実行委員

2000/03 - 2000/03
19th International Colloquium on Magnetic Films and Surfaces　Local Committee

2006/08 -
International Conference on Magnetism 2006　Program Committee

2006/08 -
19th International Colloquium on Magnetic Films and Surfaces　現地委員会

2006/08 -
International Conference on Magnetism 2006　プログラム委員会

2006/08 -
INTERMAG 2005　Program Committee

2005/04 -
INTERMAG 2005　プログラム委員会

2005/04 -
2004年秋季応用物理学会学術講演会　現地実行委員

2004/09 -
2004年秋季応用物理学会学術講演会　現地実行委員

2004/09 -
International Symposium on Nanoscale Magnetism and Transport　Local Committee

2000/03 -

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Professional Memberships 4

日本物理学会
電子情報通信学会
日本磁気学会
応用物理学会

Research Interests 3

interface structure
spin injection
ferromagneitc tunnel junction

Research Areas 4

Natural sciences / Magnetism, superconductivity, and strongly correlated systems /
Nanotechnology/Materials / Thin-film surfaces and interfaces /
Nanotechnology/Materials / Crystal engineering / Magnetic Proporty
Nanotechnology/Materials / Applied materials / Magnetic Proporty

Awards 11

支部貢献賞

2020/12　応用物理学会東北支部　応用物理学会東北支部における顕著な貢献
フェロー

2018/09　日本磁気学会　日本磁気学会フェロー
第23回業績賞

2018/09　日本磁気学会　強磁性トンネル接合の高性能化とスピントロニクスデバイスへの応用
第9回（2015年度）応用物理学会フェロー表彰

2015/09/13　応用物理学会　スピンダイナミクスの先導的研究とスピンデバイス高性能化の研究
The 74th JSAP Autumn Meeting, 2013, Poster Award

2013/10/01　応用物理学会　Magnetization dynamics in Mn-Ga/Fe exchange coupled bilayer thin films
第34回（2012年度）応用物理学会論文賞

2012/09　応用物理学会　Large Magnetoresistance Effect in Epitaxial Co2Fe0.4Mn0.6Si/Ag/Co2Fe0.4Mn0.6Si Devices
日本磁気学会平成20年度論文賞

2008/09　日本磁気学会　Co2MnSiを用いた強磁性トンネル接合における極高スピン分極率の実現
第39回原田研究奨励賞

1999/11/04　財団法人金属研究助成会　トンネル顕微鏡を用いた強磁性トンネル接合用超薄Al酸化膜の局所伝導特性解析
日本応用磁気学会平成９年度論文賞

1997/07/01　日本応用磁気学会　強磁性トンネル接合における絶縁障壁と磁気抵抗
日本化学会第71秋季年会シンポジウム賞

1996/12/17　日本化学会　高分子フェロセン誘導体薄膜における超構造と磁気特性
トーキン科学技術振興財団研究奨励賞

1995/03/06　トーキン科学技術振興財団　LB法による有機人工格子薄膜の作製とその電磁気的性質に関する基礎的研究

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Papers 437

TaFeB spacer for soft magnetic composite free layer in CoFeB/MgO/CoFeB-based magnetic tunnel junction Peer-reviewed

Takafumi Nakano, Kosuke Fujiwara, Seiji Kumagai, Yasuo Ando, Mikihiko Oogane

Applied Physics Letters　122　(7)　072405　2023/02/13

DOI： 10.1063/5.0132866 　
Tunnel anisotropic magnetoresistance in magnetic tunnel junctions using FeAlSi Peer-reviewed

S. Akamatsu, T. Nakano, Muftah Al-Mahdawi, W. Yupeng, M. Tsunoda, Y. Ando, M. Oogane

AIP Advances　13　(2)　025005　2023/02/01

DOI： 10.1063/9.0000440 　
Development of Magnetocardiograph without Magnetically Shielded Room Using High-Detectivity TMR Sensors

Koshi Kurashima, Makoto Kataoka, Takafumi Nakano, Kosuke Fujiwara, Seiichi Kato, Takenobu Nakamura, Masaki Yuzawa, Masanori Masuda, Kakeru Ichimura, Shigeki Okatake, Yoshitaka Moriyasu, Kazuhiro Sugiyama, Mikihiko Oogane, Yasuo Ando, Seiji Kumagai, Hitoshi Matsuzaki, Hidenori Mochizuki

Sensors　23　(2)　646-646　2023/01/06
Publisher: MDPI AG
DOI： 10.3390/s23020646 　

eISSN： 1424-8220

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A magnetocardiograph that enables the clear observation of heart magnetic field mappings without magnetically shielded rooms at room temperatures has been successfully manufactured. Compared to widespread electrocardiographs, magnetocardiographs commonly have a higher spatial resolution, which is expected to lead to early diagnoses of ischemic heart disease and high diagnostic accuracy of ventricular arrhythmia, which involves the risk of sudden death. However, as the conventional superconducting quantum interference device (SQUID) magnetocardiographs require large magnetically shielded rooms and huge running costs to cool the SQUID sensors, magnetocardiography is still unfamiliar technology. Here, in order to achieve the heart field detectivity of 1.0 pT without magnetically shielded rooms and enough magnetocardiography accuracy, we aimed to improve the detectivity of tunneling magnetoresistance (TMR) sensors and to decrease the environmental and sensor noises with a mathematical algorithm. The magnetic detectivity of the TMR sensors was confirmed to be 14.1 pTrms on average in the frequency band between 0.2 and 100 Hz in uncooled states, thanks to the original multilayer structure and the innovative pattern of free layers. By constructing a sensor array using 288 TMR sensors and applying the mathematical magnetic shield technology of signal space separation (SSS), we confirmed that SSS reduces the environmental magnetic noise by −73 dB, which overtakes the general triple magnetically shielded rooms. Moreover, applying digital processing that combined the signal average of heart magnetic fields for one minute and the projection operation, we succeeded in reducing the sensor noise by about −23 dB. The heart magnetic field resolution measured on a subject in a laboratory in an office building was 0.99 pTrms and obtained magnetocardiograms and current arrow maps as clear as the SQUID magnetocardiograph does in the QRS and ST segments. Upon utilizing its superior spatial resolution, this magnetocardiograph has the potential to be an important tool for the early diagnosis of ischemic heart disease and the risk management of sudden death triggered by ventricular arrhythmia.
Scalp attached tangential magnetoencephalography using tunnel magneto-resistive sensors

Akitake Kanno, Nobukazu Nakasato, Mikihiko Oogane, Kosuke Fujiwara, Takafumi Nakano, Tadashi Arimoto, Hitoshi Matsuzaki, Yasuo Ando

Scientific Reports　12　(1)　2022/12
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41598-022-10155-6 　

eISSN： 2045-2322

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Abstract Non-invasive human brain functional imaging with millisecond resolution can be achieved only with magnetoencephalography (MEG) and electroencephalography (EEG). MEG has better spatial resolution than EEG because signal distortion due to inhomogeneous head conductivity is negligible in MEG but serious in EEG. However, this advantage has been practically limited by the necessary setback distances between the sensors and scalp, because the Dewar vessel containing liquid helium for superconducting quantum interference devices (SQUIDs) requires a thick vacuum wall. Latest developments of high critical temperature (high-T_c) SQUIDs or optically pumped magnetometers have allowed closer placement of MEG sensors to the scalp. Here we introduce the use of tunnel magneto-resistive (TMR) sensors for scalp-attached MEG. Improvement of TMR sensitivity with magnetic flux concentrators enabled scalp-tangential MEG at 2.6 mm above the scalp, to target the largest signal component produced by the neural current below. In a healthy subject, our single-channel TMR-MEG system clearly demonstrated the N20m, the initial cortical component of the somatosensory evoked response after median nerve stimulation. Multisite measurement confirmed a spatially and temporally steep peak of N20m, immediately above the source at a latency around 20 ms, indicating a new approach to non-invasive functional brain imaging with millimeter and millisecond resolutions.
てんかん診療の近未来〜デバイスと医薬品開発の最前線〜トンネル磁気抵抗効果を用いた頭皮密着型脳磁計の開発

菅野彰剛, 神一敬, 柿坂庸介, 石田誠, 中里信和, 大兼幹夫, 安藤康夫

てんかん研究　40　(2)　308-308　2022/08
Publisher: (一社)日本てんかん学会
ISSN： 0912-0890

eISSN： 1347-5509
Magnetic tunnel junctions using epitaxially grown FeAlSi electrode with soft magnetic property

Shoma Akamatsu, Mikihiko Oogane, Masakiyo Tsunoda, Yasuo Ando

AIP Advances　12　(7)　075021-075021　2022/07/01
Publisher: AIP Publishing
DOI： 10.1063/5.0094619 　

eISSN： 2158-3226

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Magnetic tunnel junctions (MTJs) with (001)-oriented D0₃-FeAlSi epitaxial films, which have both soft magnetic properties and surface flatness, were fabricated and characterized. A tunnel magnetoresistance (TMR) ratio of 121% was observed, and a relatively low switching field was also confirmed, reflecting the soft magnetic property of FeAlSi. However, the results of the cross-sectional TEM image of the MTJ and the bias dependence of the TMR ratio indicate that the FeAlSi/MgO interface is probably oxidized. Therefore, since an insertion layer at the interface can suppress oxidation and further improve the TMR ratio, MTJs using FeAlSi epitaxial films are promising structures suitable for applications such as MTJ-based magnetic sensors and worthy of further investigation.
Guidelines for attaining optimal soft magnetic properties in FeAlSi films

Shoma Akamatsu, Mikihiko Oogane, Masakiyo Tsunoda, Yasuo Ando

Applied Physics Letters　120　(24)　242406-242406　2022/06/13
Publisher: AIP Publishing
DOI： 10.1063/5.0086322 　

ISSN： 0003-6951

eISSN： 1077-3118

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Nm-order FeAlSi epitaxial films with a partially D0₃-ordered structure were grown on MgO substrates, and ideal soft magnetic properties were obtained. We found that the sign of the magnetocrystalline anisotropy constant K₁ changes with increasing annealing temperature for certain FeAlSi compositions. This is caused by a change in the volume balance of the ordered phases with the annealing process and the point at which K₁ ∼ 0 shifts to the Al-rich concentration as the degree of D0₃-ordering decreases. K₁ was precisely measured by ferromagnetic resonance under the optimal condition, and the value of 1.6 × 10² (erg/cc) was obtained, which is comparable to that of bulk. The uniaxial component of the magnetic anisotropy due to magnetostriction was small, and a fourfold symmetric component due to magnetocrystalline anisotropy was dominant.
Control of sensitivity in vortex-type magnetic tunnel junction magnetometer sensors by the pinned layer geometry

Motoki Endo, Muftah Al-Mahdawi, Mikihiko Oogane, Yasuo Ando

Journal of Physics D: Applied Physics　55　(19)　195001-195001　2022/05/12
Publisher: IOP Publishing
DOI： 10.1088/1361-6463/ac5080 　

ISSN： 0022-3727

eISSN： 1361-6463

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Abstract The tuning of sensitivity and dynamic range in linear magnetic sensors is required in various applications. We demonstrate the control and design of the sensitivity in magnetic tunnel junction (MTJ) sensors with a vortex-type sensing layer. In this work, we develop sensor MTJs with NiFe sensing layers having a vortex magnetic configuration. We demonstrate that by varying the pinned layer size, the sensitivity to magnetic field is tuned linearly. We obtain a high magnetoresistance ratio of 140%, and we demonstrate a controllable sensitivity from 0.85% Oe⁻¹ to 4.43% Oe⁻¹, while keeping the vortex layer fixed in size. We compare our experimental results with micromagnetic simulations. We find that the linear displacement of vortex core by an applied field makes the design of vortex sensors simple. The control of the pinned layer geometry is an effective method to increase the sensitivity, without affecting the vortex state of the sensing layer. Furthermore, we propose that the location of the pinned layer can be used to realize more sensing functionalities from a single sensor.
Observation of unconventional spin-polarization induced spin–orbit torque in L1₂-ordered antiferromagnetic Mn₃Pt thin films

Longjie Yu, Shutaro Karube, Min Liu, Masakiyo Tsunoda, Mikihiko Oogane, Yasuo Ando

Applied Physics Express　15　(3)　033002-033002　2022/03/01
Publisher: IOP Publishing
DOI： 10.35848/1882-0786/ac52d7 　

ISSN： 1882-0778

eISSN： 1882-0786

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Abstract Non-collinear antiferromagnets exhibit richer magneto-transport properties compared to nonmagnetic materials due to the topological spin structure they possess, which allows us to manipulate the charge-spin conversion more freely by taking advantage of the chirality. In this work, we explore the unconventional spin–orbit torque of L1₂-ordered Mn₃Pt with a triangular spin structure. We observed an unconventional spin–orbit torque along the x-direction for the (001)-oriented L1₂ Mn₃Pt and found that it has a sign reversal behavior relative to the crystalline orientation. This generation of unconventional spin–orbit torque can be interpreted as stemming from the magnetic spin Hall effect.
最新のセンサー系から見た心臓磁場計測技術と脳磁場計測に向けた展望室温動作TMRセンサーを用いたリアルタイム心磁場および体性感覚誘発脳磁場の計測

藤原耕輔, 菅野彰剛, 中野貴文, 熊谷静似, 松崎斉, 有本直, 大兼幹彦, 中里信和, 安藤康夫

日本生体磁気学会誌　35　(1)　76-77　2022
Publisher: 日本生体磁気学会
ISSN： 0915-0374
最新のセンサー系から見た心臓磁場計測技術と脳磁場計測に向けた展望室温動作TMRセンサーを用いたリアルタイム心磁場および体性感覚誘発脳磁場の計測

藤原耕輔, 菅野彰剛, 中野貴文, 熊谷静似, 松崎斉, 有本直, 大兼幹彦, 中里信和, 安藤康夫

日本生体磁気学会誌　35　(1)　76-77　2022
Publisher: 日本生体磁気学会
ISSN： 0915-0374
Deep Learning Models for Magnetic Cardiography Edge Sensors Implementing Noise Processing and Diagnostics

Sadman Sakib, Mostafa M. Fouda, Muftah Al-Mahdawi, Attayeb Mohsen, Mikihiko Oogane, Yasuo Ando, Zubair Md. Fadlullah

IEEE Access　10　2656-2668　2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/access.2021.3138976 　

eISSN： 2169-3536
Sub-pT magnetic field detection by tunnel magneto-resistive sensors

Mikihiko Oogane, Kosuke Fujiwara, Akitake Kanno, Takafumi Nakano, Hiroshi Wagatsuma, Tadashi Arimoto, Shigemi Mizukami, Seiji Kumagai, Hitoshi Matsuzaki, Nobukazu Nakasato, Yasuo Ando

Applied Physics Express　14　(12)　123002-123002　2021/12/01
Publisher: IOP Publishing
DOI： 10.35848/1882-0786/ac3809 　

ISSN： 1882-0778

eISSN： 1882-0786

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<title>Abstract</title> We developed tunnel magneto-resistive (TMR) sensors based on magnetic tunnel junctions (MTJs) that are able to detect a weak, sub-pT, magnetic field at a low frequency. Small detectivities of 0.94 pT/Hz^1/2 at 1 Hz and 0.05 pT/Hz^1/2 at 1 kHz were achieved by lowering the resistance of MTJs and enhancement of the signal using a thick CoFeSiB layer and magnetic flux concentrators. We demonstrated real-time measurement of magnetocardiography (MCG) and nuclear magnetic resonance (NMR) of protons using developed sensors. This result shows that both MCG and NMR can be measured by the same measurement system with ultra-sensitive TMR sensors.
室温生体磁気計測の進歩:SQUIDを超えて TMRセンサの原理と心磁図計測

大兼幹彦, 菅野彰剛, 藤原耕輔, 中野貴文, 熊谷静似, 松崎斉, 中里信和, 安藤康夫

臨床神経生理学　49　(5)　299-299　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
室温生体磁気計測の進歩:SQUIDを超えて頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学　49　(5)　300-300　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
第32回小児脳機能研究会:臨床神経生理からみた小児の機能評価-中枢から末梢まで- 頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学　49　(5)　371-371　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
室温生体磁気計測の進歩:SQUIDを超えて TMRセンサの原理と心磁図計測

大兼幹彦, 菅野彰剛, 藤原耕輔, 中野貴文, 熊谷静似, 松崎斉, 中里信和, 安藤康夫

臨床神経生理学　49　(5)　299-299　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
室温生体磁気計測の進歩:SQUIDを超えて頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学　49　(5)　300-300　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
第32回小児脳機能研究会:臨床神経生理からみた小児の機能評価-中枢から末梢まで- 頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学　49　(5)　371-371　2021/10
Publisher: (一社)日本臨床神経生理学会
ISSN： 1345-7101

eISSN： 2188-031X
Quadratic magnetoelectric effect during field cooling in sputter grown Cr2O3 films

Muftah Al-Mahdawi, Tomohiro Nozaki, Mikihiko Oogane, Hiroshi Imamura, Yasuo Ando, Masashi Sahashi

Physical Review Materials　5　(9)　2021/09/14
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevmaterials.5.094406 　

eISSN： 2475-9953
Noise-Removal from Spectrally-Similar Signals Using Reservoir Computing for MCG Monitoring

Sadman Sakib, Mostafa M. Fouda, Muftah Al-Mahdawi, Attayeb Mohsen, Mikihiko Oogane, Yasuo Ando, Zubair Md Fadlullah

ICC 2021 - IEEE International Conference on Communications　2021/06
Publisher: IEEE
DOI： 10.1109/icc42927.2021.9500993 　
Tunnel magnetoresistance in magnetic tunnel junctions with FeAlSi electrode

Shoma Akamatsu, Mikihiko Oogane, Zhenhu Jin, Masakiyo Tsunoda, Yasuo Ando

AIP Advances　11　(4)　2021/04/01
Publisher: American Institute of Physics Inc.
DOI： 10.1063/5.0041571 　

ISSN： 2158-3226
Serial MTJ-Based TMR Sensors in Bridge Configuration for Detection of Fractured Steel Bar in Magnetic Flux Leakage Testing

Zhenhu Jin, Muhamad Arif Ihsan Mohd Noor Sam, Mikihiko Oogane, Yasuo Ando

Sensors　21　(2)　668-668　2021/01/19
Publisher: MDPI AG
DOI： 10.3390/s21020668 　

eISSN： 1424-8220

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Thanks to high sensitivity, excellent scalability, and low power consumption, magnetic tunnel junction (MTJ)-based tunnel magnetoresistance (TMR) sensors have been widely implemented in various industrial fields. In nondestructive magnetic flux leakage testing, the magnetic sensor plays a significant role in the detection results. As highly sensitive sensors, integrated MTJs can suppress frequency-dependent noise and thereby decrease detectivity; therefore, serial MTJ-based sensors allow for the design of high-performance sensors to measure variations in magnetic fields. In the present work, we fabricated serial MTJ-based TMR sensors and connected them to a full Wheatstone bridge circuit. Because noise power can be suppressed by using bridge configuration, the TMR sensor with Wheatstone bridge configuration showed low noise spectral density (0.19 μV/Hz0.5) and excellent detectivity (5.29 × 10−8 Oe/Hz0.5) at a frequency of 1 Hz. Furthermore, in magnetic flux leakage testing, compared with one TMR sensor, the Wheatstone bridge TMR sensors provided a higher signal-to-noise ratio for inspection of a steel bar. The one TMR sensor system could provide a high defect signal due to its high sensitivity at low lift-off (4 cm). However, as a result of its excellent detectivity, the full Wheatstone bridge-based TMR sensor detected the defect even at high lift-off (20 cm). This suggests that the developed TMR sensor provides excellent detectivity, detecting weak field changes in magnetic flux leakage testing.
Measurement of somatosensory evoked magnetic fields at room temperature using a TMR sensor system

Kanno Akitake, Oogane mikihiko, Fujiwara Kosuke, Matsuzaki Hitoshi, Ando Yasuo, Nakasato Nobukazu

Transactions of Japanese Society for Medical and Biological Engineering　59　752-753　2021
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.Annual59.752 　

ISSN： 1347-443X

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Measurement of somatosensory magnetic evoked fields (SEFs), using a magnetoencephalography (MEG) system with superconducting quantum interference devices (SQUIDs), are one of the most popular diagnostic tools to evaluate and localize brain function in human. However, wall size of liquid helium container for SQUIDs has been constituting a barrier to minimize sensor-source distance, the most important factor for spatial resolution. We recently achieved a success to measure human magneto-cardiogram and spontaneous alpha activity of MEG at room temperature using newly developed tunnel magneto-resistive (TMR) sensors. Here we applied a TMR sensor system to measure SEFs, challenging MEG signals due to their weakness. In a normal volunteer subject, using a standard stimulation protocol of median nerve stimulus, a TMR sensor system combined with magnetic flux concentrators, and a signal averaging technique up to 5,000 times, we successfully demonstrated a clear N20m peak, the first and weakest component of SEFs.
Measurement of somatosensory evoked magnetic fields at room temperature using a TMR sensor system

Kanno Akitake, Oogane mikihiko, Fujiwara Kosuke, Matsuzaki Hitoshi, Ando Yasuo, Nakasato Nobukazu

Transactions of Japanese Society for Medical and Biological Engineering　59　243-243　2021
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.Annual59.243 　

ISSN： 1347-443X

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Measurement of somatosensory magnetic evoked fields (SEFs), using a magnetoencephalography (MEG) system with superconducting quantum interference devices (SQUIDs), are one of the most popular diagnostic tools to evaluate and localize brain function in human. However, wall size of liquid helium container for SQUIDs has been constituting a barrier to minimize sensor-source distance, the most important factor for spatial resolution. We recently achieved a success to measure human magneto-cardiogram and spontaneous alpha activity of MEG at room temperature using newly developed tunnel magneto-resistive (TMR) sensors. Here we applied a TMR sensor system to measure SEFs, challenging MEG signals due to their weakness. In a normal volunteer subject, using a standard stimulation protocol of median nerve stimulus, a TMR sensor system combined with magnetic flux concentrators, and a signal averaging technique up to 5,000 times, we successfully demonstrated a clear N20m peak, the first and weakest component of SEFs.
トンネル磁気抵抗素子を用いた室温脳磁計による体性感覚誘発磁界の測定

菅野彰剛, 大兼幹彦, 藤原耕輔, 松崎斉, 安藤康夫, 中里信和

日本生体磁気学会誌　34　(1)　112-113　2021
Publisher: 日本生体磁気学会
ISSN： 0915-0374
Highly-sensitive magnetic sensor for detecting magnetic nanoparticles based on magnetic tunnel junctions at a low static field

Z. Jin, Thomas Myeongseok Koo, Myeong Soo Kim, M. Al-Mahdawi, M. Oogane, Y. Ando, Young Keun Kim

AIP Advances　11　(1)　015046-015046　2021/01/01
Publisher: AIP Publishing
DOI： 10.1063/9.0000189 　

eISSN： 2158-3226
Detection of Small Magnetic Fields Using Serial Magnetic Tunnel Junctions with Various Geometrical Characteristics

Zhenhu Jin, Yupeng Wang, Kosuke Fujiwara, Mikihiko Oogane, Yasuo Ando

Sensors　20　(19)　5704-5704　2020/10/07
Publisher: MDPI AG
DOI： 10.3390/s20195704 　

eISSN： 1424-8220

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Thanks to their high magnetoresistance and integration capability, magnetic tunnel junction-based magnetoresistive sensors are widely utilized to detect weak, low-frequency magnetic fields in a variety of applications. The low detectivity of MTJs is necessary to obtain a high signal-to-noise ratio when detecting small variations in magnetic fields. We fabricated serial MTJ-based sensors with various junction area and free-layer electrode aspect ratios. Our investigation showed that their sensitivity and noise power are affected by the MTJ geometry due to the variation in the magnetic shape anisotropy. Their MR curves demonstrated a decrease in sensitivity with an increase in the aspect ratio of the free-layer electrode, and their noise properties showed that MTJs with larger junction areas exhibit lower noise spectral density in the low-frequency region. All of the sensors were able detect a small AC magnetic field (Hrms = 0.3 Oe at 23 Hz). Among the MTJ sensors we examined, the sensor with a square-free layer and large junction area exhibited a high signal-to-noise ratio (4792 ± 646). These results suggest that MTJ geometrical characteristics play a critical role in enhancing the detectivity of MTJ-based sensors.
Scaling of quadratic and linear magneto-optic Kerr effect spectra with L2(1) ordering of Co2MnSi Heusler compound

Robin Silber, Daniel Kral, Ondrej Stejskal, Takahide Kubota, Yasuo Ando, Jaromir Pistora, Martin Veis, Jaroslav Hamrle, Timo Kuschel

APPLIED PHYSICS LETTERS　116　(26)　2020/06

DOI： 10.1063/5.0008427 　

ISSN： 0003-6951

eISSN： 1077-3118
AI Aided Noise Processing of Spintronic Based IoT Sensor for Magnetocardiography Application

Attayeb Mohsen, Muftah Al-Mahdawi, Mostafa M. Fouda, Mikihiko Oogane, Yasuo Ando, Zubair Md Fadlullah

ICC 2020 - 2020 IEEE International Conference on Communications (ICC)　2020/06
Publisher: IEEE
DOI： 10.1109/icc40277.2020.9148617 　
Efficiency of ultrafast optically induced spin transfer in Heusler compounds

Daniel Steil, Jakob Walowski, Felicitas Gerhard, Tobias Kiessling, Daniel Ebke, Andy Thomas, Takahide Kubota, Mikihiko Oogane, Yasuo Ando, Johannes Otto, Andreas Mann, Moritz Hofherr, Peter Elliott, John Kay Dewhurst, Günter Reiss, Laurens Molenkamp, Martin Aeschlimann, Mirko Cinchetti, Markus Münzenberg, Sangeeta Sharma, Stefan Mathias

Physical Review Research　2　(2)　2020/05/20
Publisher: American Physical Society
DOI： 10.1103/PhysRevResearch.2.023199 　

ISSN： 2643-1564
High-Temperature Magnetic Tunnel Junction Magnetometers Based on L1$_0$-PtMn Pinned Layer

Sina Ranjbar, Muftah Al-Mahdawi, Mikihiko Oogane, Yasuo Ando

IEEE Sensors Letters　4　(5)　1-4　2020/05
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/lsens.2020.2991654 　

eISSN： 2475-1472
Controlling domain configuration of the sensing layer for magnetic tunneling junctions by using exchange bias

Sina Ranjbar, Muftah Al-Mahdawi, Mikihiko Oogane, Yasuo Ando

AIP Advances　10　(2)　025119-025119　2020/02/01
Publisher: AIP Publishing
DOI： 10.1063/1.5130486 　

eISSN： 2158-3226
Large spin signals in n+ -Si/MgO/ Co2Fe0.4Mn0.6Si lateral spin-valve devices Peer-reviewed

T. Koike, M. Oogane, M. Tsunoda, Y. Ando

Journal of Applied Physics　127　(8)　085306-1-085306-8　2020/02
Fabrication and evaluation of highly c-plane oriented Mn3Sn thin films Peer-reviewed

T. Ikeda, M. Tsunoda, M. Oogane, S. Oh, T. Morita, Y. Ando

AIP Advances　10　015310-1-015310-5　2020/01
Fabrication of soft-magnetic FeAlSi thin films with nm-order thickness for the free layer of magnetic tunnel junction based sensors Peer-reviewed

S. Akamatsu, M. Oogane, M. Tsunoda, Y. Ando

AIP Advances　10　015302-1-015302-4　2020/01
Composition dependence of the secondorder interfacial magnetic anisotropy for MgO/CoFeB/Ta films Peer-reviewed

T. Ogasawara, M. Oogane, M. Al-Mahdawi, M. Tsunoda, Y. Ando

AIP Advances　9　125053-1-125053-5　2019/12
Polycrystalline Co2Fe0.4Mn0.6Si Heusler alloy thin films with high B2 ordering and small magnetic anisotropy for magnetic tunnel junction based sensors Peer-reviewed

N. Kudo, M. Oogane, M. Tsunoda, Y. Ando

AIP Advances　9　125036-1-125036-4　2019/12
Effect of second-order magnetic anisotropy on nonlinearity of conductance in CoFeB/MgO/CoFeB magnetic tunnel junction for magnetic sensor devices Peer-reviewed

T. Ogasawara, M. Oogane, M. Al-Mahdawi, M. Tsunoda, Y. Ando

Scientific Reports　9　17018-1-17018-9　2019/11
Investigation of a Magnetic Tunnel Junction Based Sensor for the Detection of Defects in Reinforced Concrete at High Lift-Off

Muhamad Arif Ihsan Mohd Noor Sam, Zhenhu Jin, Mikihiko Oogane, Yasuo Ando

Sensors　19　(21)　4718-4718　2019/10/30
Publisher: MDPI AG
DOI： 10.3390/s19214718 　

eISSN： 1424-8220

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Magnetic flux leakage (MFL) testing is a method of non-destructive testing (NDT), whereby the material is magnetized, and when a defect is present, the magnetic flux lines break out of the material. The magnitude of the leaked magnetic flux decreases as the lift-off (distance from the material) increases. Therefore, for detection at high lift-off, a sensitive magnetic sensor is required. To increase the output sensitivity, this paper proposes the application of magnetic tunnel junction (MTJ) sensors in a bridge circuit for the NDT of reinforced concrete at high lift-off. MTJ sensors were connected to a full-bridge circuit, where one side of the arm has two MTJ sensors connected in series, and the other contains a resistor and a variable resistor. Their responses towards a bias magnetic field were measured, and, based on the results, the sensor circuit sensitivity was 0.135 mV/mT. Finally, a reinforced concrete specimen with a 1 cm gap in the center was detected. The sensor module (with an amplifier and low pass filter circuits) could determine the gap even at 50 cm, suggesting that MTJ sensors have the potential to detect defects at high lift-off values and have a promising future in the field of NDT.
Composition dependence of exchange anisotropy in PtxMn100−x/CoyFe100-y films Peer-reviewed

S. Ranjbar, M. Tsunoda, M. Al-Mahdawi, M. Oogane, Y. Ando

IEEE Magnetics Letters　10　4505905-1-4505905-5　2019/10
In-plane and perpendicular exchange bias effect induced by an antiferromagnetic D0(19) Mn2FeGa thin film Peer-reviewed

Ogasawara Takahiro, Jackson Edward, Tsunoda Masakiyo, Ando Yasuo, Hirohata Atsufumi

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　484　307-312　2019/08

DOI： 10.1016/j.jmmm.2019.04.024 　

ISSN： 0304-8853

eISSN： 1873-4766
Improvement of Large Anomalous Hall Effect in Polycrystalline Antiferromagnetic Mn3+xSn Thin Films Peer-reviewed

Ikeda Tomoki, Tsunoda Masakiyo, Oogane Mikihiko, Oh Seungjun, Morita Tadashi, Ando Yasuo

IEEE TRANSACTIONS ON MAGNETICS　55　(7)　2019/07

DOI： 10.1109/TMAG.2019.2899223 　

ISSN： 0018-9464
Controlled growth and magnetic property of a-plane-oriented Mn3Sn thin films Peer-reviewed

Oh Seungjun, Morita Tadashi, Ikeda Tomoki, Tsunoda Masakiyo, Oogane Mikihiko, Ando Yasuo

AIP ADVANCES　9　(3)　2019/03

DOI： 10.1063/1.5079688 　

ISSN： 2158-3226
Serial magnetic tunnel junction based sensors for detecting far-side pitsin metallic specimens Peer-reviewed

Zhenhu Jin, Muhamad Arif Ihsan, Mikihiko Oogane, Kousuke Fujiwara, Yasuo Ando

Japanese Journal of AppliedPhysics　58　043003-1-043003-6　2019/03

DOI： 10.7567/1347-4065/aafe71 　
Composition dependence of exchange anisotropy in PtxMn1−x/Co70Fe30 films Peer-reviewed

Sina Ranjbar, Masakiyo Tsunoda, Mikihiko Oogane, Yasuo Ando

Japanese Journal of Applied Physics　58　043001-1-043001-5　2019/03

DOI： 10.7567/1347-4065/ab03e3 　
Structural and antiferromagnetic characterization of noncollinear D019 Mn3Ge polycrystalline film Peer-reviewed

Takahiro Ogasawara, Jun-young Kim, Yasuo Ando, Atsufumi Hirohata

Journal of Magnetism and Magnetic Materials　473　7-11　2019

DOI： 10.1016/j.jmmm.2018.10.035 　

ISSN： 0304-8853

eISSN： 1873-4766
Anomalous Hall effect in polycrystalline Mn3Sn thin films Peer-reviewed

Tomoki Ikeda, Masakiyo Tsunoda, Mikihiko Oogane, Seungjun Oh, Tadashi Morita, Yasuo Ando

APPLIED PHYSICS LETTERS　113　222405-1-222405-5　2018/11

DOI： 10.1063/1.5051495 　
Epitaxial L10-MnAl Thin Films With High Perpendicular Magnetic Anisotropy and Small Surface Roughness Peer-reviewed

Most Shahnaz Parvin, Mikihiko Oogane, Miho Kubota, Masakiyo Tsunoda, Yasuo Ando

EEE TRANSACTIONS ON MAGNETICS　54　(11)　3401704-1-3401704-4　2018/11

DOI： 10.1109/TMAG.2018.2834553 　

ISSN： 0018-9464
Effects of annealing temperature on sensing properties of magnetic-tunnel-junction-based sensors with perpendicular syntheticantiferromagnetic Co/Pt pinned layer Peer-reviewed

Takahiro Ogasawara, Mikihiko Oogane, Masakiyo Tsunoda, Yasuo Ando

Japanese Journal of AppliedPhysics　57　(11)　110308-1-110308-4　2018/10

DOI： 10.7567/JJAP.57.110308 　
Large exchange coupling field in perpendicular synthetic antiferromagnetic structures with CoPt alloy Peer-reviewed

Takahiro Ogasawara, Mikihiko Oogane, Masakiyo Tsunoda, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　57　(8)　088004-1-088004-3　2018/07

DOI： 10.7567/JJAP.57.088004 　
Fourfold symmetric anisotropic magnetoresistance in half-metallic Co2MnSi Heusler alloy thin films Peer-reviewed

Mikihiko Oogane, Anthony P. McFadden, Yohei Kota, Tobias L. Brown-Heft, Masakiyo Tsunoda, Yasuo Ando, Chris J. Palmstrøm

Japanese Journal of Applied Physics　57　(6)　063001-1-063001-4　2018/06/01
Publisher: Japan Society of Applied Physics
DOI： 10.7567/JJAP.57.063001 　

ISSN： 1347-4065 0021-4922
Low magnetic damping and large negative anisotropic magnetoresistance in half-metallic Co2-xMn1+xSi Heusler alloy films grown by molecular beam epitaxy Peer-reviewed

M.Oogane, AP.McFadden, K.Fukuda, M.Tsunoda, Y.Ando, CJ. Palmstrom

APPLIED PHYSICS LETTERS　112　(26)　262407-1-262407-5　2018/06

DOI： 10.1063/1.5030341 　
Annealing effect on interlayer exchange coupling in perpendicularly magnetized synthetic antiferromagnetic structure based on Co/Pd multilayers with ultrathin Ru spacer Peer-reviewed

Takafumi Nakano, Mikihiko Oogane, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　57　(7)　073001-1-073001-4　2018/06

DOI： 10.7567/JJAP.57.073001 　
Magnetic-sensor performance evaluated from magneto-conductance curve in magnetic tunnel junctions using in-plane or perpendicularly magnetized synthetic antiferromagnetic reference layers Peer-reviewed

T. Nakano, M. Oogane, T. Furuichi, Y. Ando

AIP Advances　8　(4)　045011-1-045011-6　2018/04/01
Publisher: American Institute of Physics Inc.
DOI： 10.1063/1.5027768 　

ISSN： 2158-3226
Room Temperature Magnetoencephalography and Magnetocardiography Measurements using TMR Sensors

Fujiwara Kousuke, Oogane Mikihiko, Kanno Akitake, Imada Masahiro, Jono Junichi, Terauchi Takashi, Okuno Tetsuo, Aritomi Yuuji, Hashimoto Kiyofumi, Morikawa Masahiro, Tsuchida Masaaki, Nakasato Nobukazu, Ando Yasuo

JSAP Annual Meetings Extended Abstracts　2018.1　2250-2250　2018/03/05
Publisher: The Japan Society of Applied Physics
DOI： 10.11470/jsapmeeting.2018.1.0_2250 　

eISSN： 2436-7613
Realization of a Spin-Wave Switch Based on the Spin-Transfer-Torque Effect Peer-reviewed

Thomas Meyer, Thomas Bracher, Frank Heussner, Alexander A. Serga, Hiroshi Naganuma, Koki Mukaiyama, Mikihiko Oogane, Yasuo Ando, Burkard Hillebrands, Philipp Pirro

IEEE Magnetics Letters　9　3102005-1-3102005-5　2018/02/07
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/LMAG.2018.2803737 　

ISSN： 1949-307X
Magnetocardiography and magnetoencephalography measurements at room temperature using tunnel magneto-resistance sensors Peer-reviewed

Kosuke Fujiwara, Mikihiko Oogane, Akitake Kanno, Masahiro Imada, Junichi Jono, Takashi Terauchi, Tetsuo Okuno, Yuuji Aritomi, Masahiro Morikawa, Masaaki Tsuchida, Nobukazu Nakasato, Yasuo Ando

Applied Physics Express　11　(2)　023001-1-023001-4　2018/02

DOI： 10.7567/APEX.11.023001 　

ISSN： 1882-0778

eISSN： 1882-0786
Characterization of spin-transfer-torque effect induced magnetization dynamics driven by short current pulses Peer-reviewed

T. Meyer, T. Brächer, F. Heussner, A. A. Serga, H. Naganuma, K. Mukaiyama, M. Oogane, Y. Ando, B. Hillebrands, P. Pirro

Applied Physics Letters　112　(2)　022401-1-022401-5　2018/01/08
Publisher: American Institute of Physics Inc.
DOI： 10.1063/1.5011721 　

ISSN： 0003-6951
Structural and Magnetic Properties in Mn2VAl Full-Heusler Epitaxial Thin Films Peer-reviewed

Kenji Fukuda, Mikihiko Oogane, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　53　(11)　2017/11

DOI： 10.1109/TMAG.2017.2697078 　

ISSN： 0018-9464

eISSN： 1941-0069
Observation of Magnetoresistance Effect in n-Type Non-Degenerate Germanium With Co2Fe0.4Mn0.6Si Heusler Alloy Electrodes Peer-reviewed

Takeo Koike, Mikihiko Oogane, Tetsurou Takada, Hidekazu Saito, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　53　(11)　2017/11

DOI： 10.1109/TMAG.2017.2704780 　

ISSN： 0018-9464

eISSN： 1941-0069
Magnetic sensor based on serial magnetic tunnel junctions for highly sensitive detection of surface cracks Peer-reviewed

Zhenhu Jin, Mikihiko Oogane, Kosuke Fujiwara, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　122　(17)　113903　2017/11

DOI： 10.1063/1.5001098 　

ISSN： 0021-8979

eISSN： 1089-7550
Micro-Focused Pulse Laser-Induced Propagating Spin Waves in Permalloy Films With Different Thicknesses Peer-reviewed

Akira Kamimaki, Satoshi Iihama, Yuta Sasaki, Yasuo Ando, Shigemi Mizukami

IEEE TRANSACTIONS ON MAGNETICS　53　(11)　4300604-1-4300604-1　2017/11

DOI： 10.1109/TMAG.2017.2707421 　

ISSN： 0018-9464

eISSN： 1941-0069
DC Bias Reversal Behavior of Spin-Torque Ferromagnetic Resonance Spectra in CoFeB/MgO/CoFeB Perpendicular Magnetic Tunnel Junction Peer-reviewed

Tian Yu, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　53　(9)　1400205-1-1400205-5　2017/09

DOI： 10.1109/TMAG.2017.2707081 　

ISSN： 0018-9464

eISSN： 1941-0069
Wide-dynamic-range magnetic sensor based on magnetic tunnel junctions using perpendicularly magnetized synthetic antiferromagnetic reference layer Peer-reviewed

T. Nakano, M. Oogane, T. Furuichi, Y. Ando

2017 IEEE International Magnetics Conference, INTERMAG 2017　2017/08/10
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/INTMAG.2017.8007558 　
Magnetic properties of ferrimagnetic (Mn1-xCox)2VAl full-Heusler epitaxial thin films Peer-reviewed

K. Fukuda, M. Oogane, Y. Ando

2017 IEEE International Magnetics Conference, INTERMAG 2017　2017/08/10
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/INTMAG.2017.8007971 　
CoFeAlB alloy with low damping and low magnetization as a candidate for spin transfer torque switching Peer-reviewed

A. Conca, T. Nakano, T. Meyer, Y. Ando, B. Hillebrands

JOURNAL OF APPLIED PHYSICS　122　(7)　073902-1-073902-5　2017/08

DOI： 10.1063/1.4998813 　

ISSN： 0021-8979

eISSN： 1089-7550
Reciprocal excitation of propagating spin waves by a laser pulse and their reciprocal mapping in magnetic metal films Peer-reviewed

A. Kamimaki, S. Iihama, Y. Sasaki, Y. Ando, S. Mizukami

PHYSICAL REVIEW B　96　(1)　014438-1-014438-11　2017/07

DOI： 10.1103/PhysRevB.96.014438 　

ISSN： 2469-9950

eISSN： 2469-9969
Thickness dependencies of structural and magnetic properties of cubic and tetragonal Heusler alloy bilayer films Peer-reviewed

R. Ranjbar, K. Z. Suzuki, A. Sugihara, Y. Ando, T. Miyazaki, S. Mizukami

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　433　195-201　2017/07

DOI： 10.1016/j.jmmm.2017.03.018 　

ISSN： 0304-8853

eISSN： 1873-4766
Estimation of surface crack dimensional characteristics by an eddy current method using a single magnetic tunnel junction device Peer-reviewed

Zhenhu Jin, Masahiko Abe, Mikihiko Oogane, Kousuke Fujiwara, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　56　(7)　1-5　2017/07

DOI： 10.7567/JJAP.56.073001 　

ISSN： 0021-4922

eISSN： 1347-4065
L1

Oogane Mikihiko, Watanabe Kenta, Saruyama Haruaki, Hosoda Masaki, Shahnaz Parvin, Kurimoto Yuta, Kubota Miho, Ando Yasuo

Jpn. J. Appl. Phys.　56　(8)　0802A2　2017/06/01
Publisher: Institute of Physics
DOI： 10.7567/JJAP.56.0802A2 　

ISSN： 0021-4922

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L1<inf>0</inf>-ordered MnAl thin films were epitaxially grown by sputtering. The film composition dependences of structural and magnetic properties were systematically investigated in the MnAl thin films. Both the L1<inf>0</inf>-ordered parameter and the perpendicular magnetic anisotropy energy strongly depended on the composition of the MnAl thin films. The MnAl thin films with a Mn composition of 53–54 at. % showed both the highest L1<inf>0</inf>-ordered parameter and the perpendicular magnetic anisotropy. The substrate and annealing temperatures were optimized to improve the magnetic properties and surface morphology. We have fabricated MnAl thin films with both a very high K<inf>u</inf>of 12 × 10⁶erg/cm³and a small surface roughness of ca. 0.2 nm by optimizing the film composition and substrate and annealing temperatures. These results are useful guidelines for the fabrication of highly L1<inf>0</inf>-ordered MnAl thin films with a large perpendicular magnetic anisotropy.
Cobalt substituted L1

Watanabe Kenta, Oogane Mikihiko, Ando Yasuo

Jpn. J. Appl. Phys.　56　(8)　0802B1　2017/06/01
Publisher: Institute of Physics
DOI： 10.7567/JJAP.56.0802B1 　

ISSN： 0021-4922

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The Co composition dependences of the structural and magnetic properties of L1<inf>0</inf>-(MnAl)<inf>1−</inf><inf>x</inf>Co<inf>x</inf>alloy films were investigated. The lattice constants of (MnAl)<inf>1−</inf><inf>x</inf>Co<inf>x</inf>films gradually changed with increasing Co content while maintaining the L1<inf>0</inf>-ordered structure below x = 0.08. The saturation magnetization gradually decreased with increasing Co content, and perpendicular magnetic anisotropy was observed below x = 0.08. In addition, Co substitution markedly improved the surface roughness of the films by decreasing the substrate temperature of (MnAl)<inf>1−</inf><inf>x</inf>Co<inf>x</inf>films. We found that both a high magnetic anisotropy and a small surface roughness can be obtained by the substitution of Co atoms into MnAl films.
Cobalt substituted L10-MnAl thin films with large perpendicular magnetic anisotropy Peer-reviewed

Kenta Watanabe, Mikihiko Oogane, Yasuo Ando

Jpn. J. Appl. Phys.　2017/06
L10-ordered MnAl thin films with high perpendicular magnetic anisotropy Invited Peer-reviewed

Mikihiko Oogane, Kenta Watanabe, Haruaki Saruyama, Masaki Hosoda, Parvin Shahnaz, Yuta Kurimoto, Miho Kubota, Yasuo Ando

Jpn. J. Appl. Phys.　2017/06
Grain-Size-Dependent Low-Temperature Electrical Resistivity of Polycrystalline Co2MnAl Heusler Alloy Thin Films Peer-reviewed

Resul Yilgin, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM　30　(6)　1577-1584　2017/06

DOI： 10.1007/s10948-016-3957-5 　

ISSN： 1557-1939

eISSN： 1557-1947
All-optical detection of magnetization precession in tunnel junctions under applied voltage Peer-reviewed

Yuta Sasaki, Kazuya Suzuki, Atsushi Sugihara, Akira Kamimaki, Satoshi Iihama, Yasuo Ando, Shigemi Mizukami

APPLIED PHYSICS EXPRESS　10　(2)　023002　2017/02

DOI： 10.7567/APEX.10.023002 　

ISSN： 1882-0778

eISSN： 1882-0786
Fabrication of orientation-controlled nanocomposite Nd2Fe14B/Mo/α–Fe multilayer films Peer-reviewed

K. Kobayashi, D. Ogawa, K. Koike, H. Kato, M. Oogane, T. Miyazaki, Y. Ando, M. Itakura

Journal of Physics, Conference series　2017
Publisher: IOP Institute of Physics
Experimental Investigation of the Temperature-Dependent Magnon Density and Its Influence on Studies of Spin-Transfer-Torque-Driven Systems Peer-reviewed

Thomas Meyer, Thomas Braecher, Frank Heussner, Alexander A. Serga, Hiroshi Naganuma, Koki Mukaiyama, Mikihiko Oogane, Yasuo Ando, Burkard Hillebrands, Philipp Pirro

IEEE MAGNETICS LETTERS　8　318005　2017

DOI： 10.1109/LMAG.2017.2734773 　

ISSN： 1949-307X
Magnetic tunnel junctions using perpendicularly magnetized synthetic antiferromagnetic reference layer for wide-dynamic-range magnetic sensors Peer-reviewed

T. Nakano, M. Oogane, T. Furuichi, Y. Ando

APPLIED PHYSICS LETTERS　110　(1)　012401　2017/01

DOI： 10.1063/1.4973462 　

ISSN： 0003-6951

eISSN： 1077-3118
Investigation of magnetic sensor properties of magnetic tunnel junctions with superparamagnetic free layer at low frequencies for biomedical imaging applications Peer-reviewed

Kyohei Ishikawa, Mikihiko Oogane, Kousuke Fujiwara, Junichi Jono, Masaaki Tsuchida, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　55　(12)　123001　2016/12

DOI： 10.7567/JJAP.55.123001 　

ISSN： 0021-4922

eISSN： 1347-4065
ナノスケール構造制御による高性能磁石創製への指針獲得 Invited

加藤宏朗, 小川大介, 小池邦博, 安藤康夫, 宮崎孝道, 板倉賢

電気学会研究会資料〜マグネティックス研究会〜　MAG-16　(178-196)　73-76　2016/11/28
Publisher: 電気学会
Influence of L1(0) order parameter on Gilbert damping constants for FePd thin films investigated by means of time-resolved magneto-optical Kerr effect Peer-reviewed

Satoshi Iihama, Akimasa Sakuma, Hiroshi Naganuma, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando

PHYSICAL REVIEW B　94　(17)　174425　2016/11

DOI： 10.1103/PhysRevB.94.174425 　

ISSN： 2469-9950

eISSN： 2469-9969
Fabrication of highly ordered Co2Fe0.4Mn0.6Si Heusler alloy films on Si substrates Peer-reviewed

Takeo Koike, Mikihiko Oogane, Atsuo Ono, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　55　(8)　088001　2016/08

DOI： 10.7567/JJAP.55.088001 　

ISSN： 0021-4922

eISSN： 1347-4065
Fermiology of possible topological insulator Tl0.5Bi2Te3 derived from hole-doped topological insulator Peer-reviewed

C. X. Trang, Z. Wang, D. Takane, K. Nakayama, S. Souma, T. Sato, T. Takahashi, A. A. Taskin, Y. Ando

Phys. Rev. B　93　241103R　2016/07/01

DOI： 10.1103/PhysRevB.93.241103 　
Quantification of a propagating spin-wave packet created by an ultrashort laser pulse in a thin film of a magnetic metal Peer-reviewed

S. Iihama, Y. Sasaki, A. Sugihara, A. Kamimaki, Y. Ando, S. Mizukami

PHYSICAL REVIEW B　94　(2)　020401　2016/07

DOI： 10.1103/PhysRevB.94.020401 　

ISSN： 2469-9950

eISSN： 2469-9969
Magnetic Tunnel Junctions With [Co/Pd]-Based Reference Layer and CoFeB Sensing Layer for Magnetic Sensor Peer-reviewed

Takafumi Nakano, Mikihiko Oogane, Takamoto Furuichi, Kenichi Ao, Hiroshi Naganuma, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　52　(7)　4001304　2016/07

DOI： 10.1109/TMAG.2016.2518188 　

ISSN： 0018-9464

eISSN： 1941-0069
Magnetic field-controlled hysteresis loop bias in orthogonal exchange-spring coupling composite magnetic films Peer-reviewed

Jun Jiang, Tian Yu, Rui Pan, Qin-Tong Zhang, Pan Liu, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Xiufeng Han

APPLIED PHYSICS EXPRESS　9　(6)　063003　2016/06

DOI： 10.7567/APEX.9.063003 　

ISSN： 1882-0778

eISSN： 1882-0786
Effect of annealing on Curie temperature and phase transition in La0.55Sr0.08Mn0.37O3 epitaxial films grown on SrTiO3 (100) substrates by reactive radio frequency magnetron sputtering Peer-reviewed

T. Ichinose, H. Naganuma, T. Miyazaki, M. Oogane, Y. Ando, T. Ueno, N. Inami, K. Ono

Materials Characterization　118　37-43　2016/05

DOI： 10.1016/j.matchar.2016.05.002 　
Structural and magnetic properties of cubic and tetragonal Heusler alloy bilayers Peer-reviewed

R. Ranjbar, K. Suzuki, A. Sugihara, Q. L. Ma, X. M. Zhang, Y. Ando, T. Miyazaki, S. Mizukami

MATERIALS & DESIGN　96　490-498　2016/04

DOI： 10.1016/j.matdes.2016.02.047 　

ISSN： 0264-1275

eISSN： 1873-4197
Observation of single-spin transport in an island-shaped CoFeB double magnetic tunnel junction prepared by magnetron sputtering Peer-reviewed

Thamrongsin Siripongsakul, Hiroshi Naganuma, Andras Kovacs, Amit Kohn, Mikihiko Oogane, Yasuo Ando

PHILOSOPHICAL MAGAZINE　96　(4)　310-319　2016/02

DOI： 10.1080/14786435.2015.1131343 　

ISSN： 1478-6435

eISSN： 1478-6443
19pPSB-43 Thickness Dependence of Spin-Wave Propagation Induced by A Pulse Laser in Permalloy Films

Kamimaki A., Iihama S., Sasaki Y., Ando Y., Mizukami S.

Meeting Abstracts of the Physical Society of Japan　71　1169-1169　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1169 　

ISSN： 2189-079X
Controlling Magnetization Switching and DC Transport Properties of Magnetic Tunnel Junctions by Mircowave Injection Peer-reviewed

Cheng Xin, Yu Guo Liu, Lin Shi, Tian Yu, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

7TH IEEE INTERNATIONAL NANOELECTRONICS CONFERENCE (INEC) 2016　2016

ISSN： 2159-3523
Ultrafast demagnetization of L1(0) FePt and FePd ordered alloys Peer-reviewed

Satoshi Iihama, Yuta Sasaki, Hiroshi Naganuma, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando

JOURNAL OF PHYSICS D-APPLIED PHYSICS　49　(3)　035002　2016/01

DOI： 10.1088/0022-3727/49/3/035002 　

ISSN： 0022-3727

eISSN： 1361-6463
Modification of the Interface Nanostructure and Magnetic Properties in Nd-Fe-B Thin Films Peer-reviewed

Kunihiro Koike, Takanao Kusano, Daisuke Ogawa, Keisuke Kobayashi, Hiroaki Kato, Mikihiko Oogane, Takamichi Miyazaki, Yasuo Ando, Masaru Itakura

NANOSCALE RESEARCH LETTERS　11　33　2016/01

DOI： 10.1186/s11671-016-1227-x 　

ISSN： 1556-276X
Low frequency noise in magnetic tunneling junctions with Co40Fe40B20/Co70.5Fe4.5Si15B10 composite free layer Peer-reviewed

Z. H. Yuan, J. F. Feng, Peng Guo, C. H. Wan, H. X. Wei, S. S. Ali, X. F. Han, T. Nakano, H. Naganuma, Y. Ando

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　398　215-219　2016/01

DOI： 10.1016/j.jmmm.2015.09.026 　

ISSN： 0304-8853

eISSN： 1873-4766
Antiferromagnetic coupling in perpendicularly magnetized cubic and tetragonal Heusler bilayers Peer-reviewed

R. Ranjbar, K. Suzuki, A. Sugihara, Q. L. Ma, X. M. Zhang, T. Miyazaki, Y. Ando, S. Mizukami

Materials Letters　160　88-91　2015/12

DOI： 10.1016/j.matlet.2015.07.118 　

ISSN： 0167-577X
Systematic Investigation on Correlation Between Sensitivity and Nonlinearity in Magnetic Tunnel Junction for Magnetic Sensor Peer-reviewed

Takafumi Nakano, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　51　(11)　4005104　2015/11

DOI： 10.1109/TMAG.2015.2448723 　

ISSN： 0018-9464

eISSN： 1941-0069
Negative exchange coupling in Nd2Fe14B(100)/α-Fe interface Peer-reviewed

Daisuke Ogawa, Kunihiro Koike, Shigemi Mizukami, Takamichi Miyazaki, Mikihiko Oogane, Yasuo Ando, Hiroaki Kato

Appl. Phys. Lett.　2015/09
Engineered Heusler Ferrimagnets with a Large Perpendicular Magnetic Anisotropy Peer-reviewed

Reza Ranjbar, Kazuya Suzuki, Atsushi Sugihara, Terunobu Miyazaki, Yasuo Ando, Shigemi Mizukami

Materials　8　(9)　6531-6542　2015/09

DOI： 10.3390/ma8095320 　

ISSN： 1996-1944
Spintronics technology and device development Peer-reviewed

Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　54　(7)　070101　2015/07

DOI： 10.7567/JJAP.54.070101 　

ISSN： 0021-4922

eISSN： 1347-4065
Intrinsic Gilbert damping constant in epitaxial Co2Fe0.4Mn0.6Si Heusler alloys films Peer-reviewed

Augustin L. Kwilu, Mikihiko Oogane, Hiroshi Naganuma, Masashi Sahashi, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　117　(17)　17D140　2015/05

DOI： 10.1063/1.4917334 　

ISSN： 0021-8979

eISSN： 1089-7550
Interfacial exchange coupling in cubic Heusler Co(2)FeZ (Z = Al and Si)/tetragonal Mn3Ga bilayers Peer-reviewed

R. Ranjbar, K. Suzuki, A. Sugihara, Q. L. Ma, X. M. Zhang, T. Miyazaki, Y. Ando, S. Mizukami

JOURNAL OF APPLIED PHYSICS　117　(17)　17A332　2015/05

DOI： 10.1063/1.4918764 　

ISSN： 0021-8979

eISSN： 1089-7550
Magnetic damping constant in Co-based full heusler alloy epitaxial films Peer-reviewed

M. Oogane, T. Kubota, H. Naganuma, Y. Ando

JOURNAL OF PHYSICS D-APPLIED PHYSICS　48　(16)　164012-1-164012-7　2015/04

DOI： 10.1088/0022-3727/48/16/164012 　

ISSN： 0022-3727

eISSN： 1361-6463
All-optical characterisation of the spintronic Heusler compound Co2Mn0.6Fe0.4Si Peer-reviewed

Thomas Sebastian, Yuki Kawada, Bjoern Obry, Thomas Braecher, Philipp Pirro, Dmytro A. Bozhko, Alexander A. Serga, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Burkard Hillebrands

JOURNAL OF PHYSICS D-APPLIED PHYSICS　48　(16)　164015-1-164015-7　2015/04

DOI： 10.1088/0022-3727/48/16/164015 　

ISSN： 0022-3727

eISSN： 1361-6463
Impact of local order and stoichiometry on the ultrafast magnetization dynamics of Heusler compounds Peer-reviewed

Daniel Steil, Oliver Schmitt, Roman Fetzer, Takahide Kubota, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Steven Rodan, Christian G. F. Blum, Benjamin Balke, Sabine Wurmehl, Martin Aeschlimann, Mirko Cinchetti

JOURNAL OF PHYSICS D-APPLIED PHYSICS　48　(16)　164016-1-164016-7　2015/04

DOI： 10.1088/0022-3727/48/16/164016 　

ISSN： 0022-3727

eISSN： 1361-6463
Probing the electronic and spintronic properties of buried interfaces by extremely low energy photoemission spectroscopy Peer-reviewed

Roman Fetzer, Benjamin Stadtmueller, Yusuke Ohdaira, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Tomoyuki Taira, Tetsuya Uemura, Masafumi Yamamoto, Martin Aeschlimann, Mirko Cinchetti

SCIENTIFIC REPORTS　5　8537-1-8537-6　2015/02

DOI： 10.1038/srep08537 　

ISSN： 2045-2322
16pPSA-34 Space and time-resolved all-optical magneto-optical Kerr effect in NiFe films

Iihama S., Sasaki Y., Ando Y., Mizukami S.

Meeting Abstracts of the Physical Society of Japan　70　846-846　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_846 　

ISSN： 2189-079X
Fabrication of Magnetic Tunnel Junctions with Full Heusler Alloy for Bio-Magnetic Field Sensor

ONO ATSUO, Oogane Mikihiko, Naganuma Hiroshi, Ando Yasuo

Transactions of Japanese Society for Medical and Biological Engineering　53　S187_01-S187_01　2015
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.53.S187_01 　

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Magnetic tunnel junctions (MTJs) have great advantages for the magnetic field sensor applications. However, a significant improvement of tunnel magneto-resistance (TMR) ratio is needed to detect a small bio-magnetic field. In this study, we fabricated MTJs with half-metallic Co₂Fe_0.4Mn_0.6Si(CFMS) Heusler alloy which are expected to increase TMR ratio. The fabricated MTJswere annealed twice to achieve sensor-type TMR curves. Figure shows the 2nd annealing temperature dependence of TMR curves. In MTJ annealed at 200℃, TMR curve showed a linear resistance response, which is required for sensor applications. This work was supported by the S-Innovation program, Japan Science and Technology Agency (JST).
Fabrication and Noise Performance of Magnetic Tunnel Junctions for Detection of Bio-magnetic Field

FUJIWARA KOSUKE, OOGANE MIKIHIKO, KATO DAIKI, JOUNO JUNICHI, NAGANUMA HIROSHI, KATSURADA HIROYUKI, ANDO YASUO

Transactions of Japanese Society for Medical and Biological Engineering　53　S187_03-S187_03　2015
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.53.S187_03 　

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MTJ is a small size device, working in room temperature with low power consumption, and is expected to enable detection of bio-magnetic field without liquid He. For the purpose of practical realization of MTJ bio-magnetic sensor, this study evaluated the signal and noise with various MgO barrier thicknesses in MTJ to reduce 1/f noise in frequency domain. Figures show MgO thickness dependence of signal voltage, noise voltage and S/N ratio measured from 18 Hz, 120 nT_p-p input signal. Both signal and noise voltage increased with increasing MgO thickness. From this relation of signal and noise, maximum 154 S/N ratio was acquired by 2.2 nm MgO thickness.
Optimization of Domain Wall Oscillations in Magnetic Nanowires Peer-reviewed

A. S. Demiray, H. Naganuma, M. Oogane, Y. Ando

IEEE MAGNETICS LETTERS　6　3700104-1-3700104-4　2015

DOI： 10.1109/LMAG.2014.2379629 　

ISSN： 1949-307X
Electrical Detection of Millimeter-Waves by Magnetic Tunnel Junctions Using Perpendicular Magnetized L1(0)-FePd Free Layer Peer-reviewed

Hiroshi Naganuma, G. Kirn, Yuki Kawada, Nobuhito Inami, Kenzo Hatakeyama, Satoshi Iihama, Khan Mohammed Nazrul Islam, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando

NANO LETTERS　15　(1)　623-628　2015/01

DOI： 10.1021/nl504114v 　

ISSN： 1530-6984

eISSN： 1530-6992
Preparation of monoclinic 0.9(BiFeO3)-0.1(BiCoO3) epitaxial films on orthorhombic YAlO3 (100) substrates by r.f. magnetron sputtering Peer-reviewed

T. Ichinose, H. Naganuma, K. Mukaiyama, M. Oogane, Y. Ando

JOURNAL OF CRYSTAL GROWTH　409　18-22　2015/01

DOI： 10.1016/j.jcrysgro.2014.09.044 　

ISSN： 0022-0248

eISSN： 1873-5002
Magnetization Dynamics and Damping for L10-FePd Thin Films with Perpendicular Magnetic Anisotropy Peer-reviewed

S. Iihama, M. Khan, H. Naganuma, M. Oogane, T. Miyazaki, S. Mizukami, Y. Ando

J. Magn. Soc. Jpn.　39　(2)　57-61　2015
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1501R004 　

ISSN： 1882-2924

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Magnetization dynamics and damping for FePd films were investigated using the all-optical time-resolved magneto-optical Kerr effect. We deposited 16-nm-thick FePd thin films on a single crystal MgO(001) substrate. Both in-plane magnetic anisotropy and perpendicular magnetic anisotropy (PMA) FePd films were fabricated using the magnetron sputtering method at various substrate temperatures T_s. The dependencies of magnetization dynamics on the external magnetic field angle at fixed external magnetic field strengths were analyzed. The effective damping constant, α_eff, for FePd films with PMA exhibited anisotropy, whereas the α_eff for FePd with in-plane magnetic anisotropy did not depend significantly on the field angle. A uniaxial crystalline magnetic anisotropy constant, K_u1, of 11 Merg/cm³ and a minimum for α_eff of 0.007 were observed for film prepared at T_s = 200°C. This α_eff value was much smaller than that for other Fe- and Co-based materials with large PMA such as L1₀-FePt alloy, Co/Pt(Pd) multilayers.
Penetration depth of transverse spin current in (001)-oriented epitaxial ferromagnetic films Peer-reviewed

Augustin L. Kwilu, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　368　333-337　2014/11

DOI： 10.1016/j.jmmm.2014.05.043 　

ISSN： 0304-8853

eISSN： 1873-4766
Non-Gilbert-damping Mechanism in a Ferromagnetic Heusler Compound Probed by Nonlinear Spin Dynamics Peer-reviewed

P. Pirro, T. Sebastian, T. Braecher, A. A. Serga, T. Kubota, H. Naganuma, M. Oogane, Y. Ando, B. Hillebrands

PHYSICAL REVIEW LETTERS　113　(22)　227601-1-227601-5　2014/11

DOI： 10.1103/PhysRevLett.113.227601 　

ISSN： 0031-9007

eISSN： 1079-7114
Low precessional damping observed for L1(0)-ordered FePd epitaxial thin films with large perpendicular magnetic anisotropy Peer-reviewed

S. Iihama, A. Sakuma, H. Naganuma, M. Oogane, T. Miyazaki, S. Mizukami, Y. Ando

APPLIED PHYSICS LETTERS　105　(14)　142403　2014/10

DOI： 10.1063/1.4897547 　

ISSN： 0003-6951

eISSN： 1077-3118
Present and perspective of bio-magnetic measurement using ferromagnetic tunnel junctions Peer-reviewed

Y. Ando, T. Nishikawa, K. Fujiwara, M. Oogane, D. Kato, H. Naganuma

Transactions of Japanese Society for Medical and Biological Engineering　52　33-OS-34　2014/08/17
Publisher: Japan Soc. of Med. Electronics and Biol. Engineering
DOI： 10.11239/jsmbe.52.OS-33 　

ISSN： 1347-443X 1881-4379
Fabrication of integrated magnetic tunnel junctions for detection of bio-magnetic field Peer-reviewed

Kosuke Fujiwara, Mikihiko Oogane, Daiki Kato, Takuo Nishikawa, Hiroshi Naganuma, Yasuo Ando

Transactions of Japanese Society for Medical and Biological Engineering　52　O-505-0-506　2014/08/17
Publisher: Japan Soc. of Med. Electronics and Biol. Engineering
DOI： 10.11239/jsmbe.52.O-505 　

ISSN： 1347-443X 1881-4379
Correlations between atomic structure and giant magnetoresistance ratio in Co-2(Fe, Mn) Si spin valves Peer-reviewed

L. Lari, K. Yoshida, P. L. Galindo, J. Sato, J. Sizeland, D. Gilks, G. M. Uddin, Z. Nedelkoski, P. J. Hasnip, A. Hirohata, M. Oogane, Y. Ando, V. K. Lazarov

JOURNAL OF PHYSICS D-APPLIED PHYSICS　47　(32)　322003-1-322003-5　2014/08

DOI： 10.1088/0022-3727/47/32/322003 　

ISSN： 0022-3727

eISSN： 1361-6463
Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer Peer-reviewed

Yuki Kawada, Hiroshi Naganuma, Ahmet Serdar Demiray, Mikihiko Oogane, Yasuo Ando

APPLIED PHYSICS LETTERS　105　(5)　052407　2014/08

DOI： 10.1063/1.4892077 　

ISSN： 0003-6951

eISSN： 1077-3118
Preparation of a heteroepitaxial LaxSryMnzO3/BiFeO3 bilayer by r.f. magnetron sputtering with various oxygen gas flow ratios Peer-reviewed

H. Naganuma, T. Ichinose, H. A. Begum, S. Sato, X. F. Han, T. Miyazaki, In-T. Bae, M. Oogane, Y. Ando

AIP ADVANCES　4　(8)　087133　2014/08

DOI： 10.1063/1.4893998 　

ISSN： 2158-3226
Ultrafast magnetization dynamics in Co-based Heusler compounds with tuned chemical ordering Peer-reviewed

D. Steil, O. Schmitt, R. Fetzer, T. Kubota, H. Naganuma, M. Oogane, Y. Ando, A. K. Suszka, O. Idigoras, G. Wolf, B. Hillebrands, A. Berger, M. Aeschlimann, M. Cinchetti

NEW JOURNAL OF PHYSICS　16　(6)　63068-1-63068-17　2014/06

DOI： 10.1088/1367-2630/16/6/063068 　

ISSN： 1367-2630
Magnetization dynamics for L1(0) MnGa/Fe exchange coupled bilayers Peer-reviewed

S. Mizukami, T. Kubota, S. Iihama, R. Ranjbar, Q. Ma, X. Zhang, Y. Ando, T. Miyazaki

JOURNAL OF APPLIED PHYSICS　115　(17)　17C119-1-17C119-3　2014/05

DOI： 10.1063/1.4868087 　

ISSN： 0021-8979

eISSN： 1089-7550
Spin-dependent transport behavior in C-60 and Alq(3) based spin valves with a magnetite electrode (invited) Invited Peer-reviewed

Xianmin Zhang, Shigemi Mizukami, Qinli Ma, Takahide Kubota, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　115　(17)　172608-1-172608-6　2014/05

DOI： 10.1063/1.4870154 　

ISSN： 0021-8979

eISSN： 1089-7550
Tunnel magnetoresistance effect using perpendicularly magnetized tetragonal and cubic Mn-Co-Ga Heusler alloy electrode Peer-reviewed

T. Kubota, S. Mizukami, Q. L. Ma, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF APPLIED PHYSICS　115　(17)　17C704-1-17C704-3　2014/05

DOI： 10.1063/1.4855016 　

ISSN： 0021-8979

eISSN： 1089-7550
Static and dynamic magnetic properties of cubic Mn-Co-Ga Heusler films Peer-reviewed

A. S. Demiray, T. Kubota, S. Iihama, S. Mizukami, T. Miyazaki, H. Naganuma, M. Oogane, Y. Ando

JOURNAL OF APPLIED PHYSICS　115　(17)　17D133-1-17D133-3　2014/05

DOI： 10.1063/1.4864250 　

ISSN： 0021-8979

eISSN： 1089-7550
Gilbert damping constants of Ta/CoFeB/MgO(Ta) thin films measured by optical detection of precessional magnetization dynamics Peer-reviewed

Satoshi Iihama, Shigemi Mizukami, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

PHYSICAL REVIEW B　89　(17)　174416-1-174416-6　2014/05

DOI： 10.1103/PhysRevB.89.174416 　

ISSN： 1098-0121

eISSN： 1550-235X
Effect of Dy/Nd double layer on coercivity in Nd-Fe-B thin films Peer-reviewed

K. Koike, J. Umezawa, H. Ishikawa, D. Ogawa, Y. Mizuno, H. Kato, T. Miyazaki, Y. Ando

JOURNAL OF APPLIED PHYSICS　115　(17)　17A735　2014/05

DOI： 10.1063/1.4866893 　

ISSN： 0021-8979

eISSN： 1089-7550
Half-metal CPP GMR sensor for magnetic recording Peer-reviewed

Z. Diao, M. Chapline, Y. Zheng, C. Kaiser, A. Ghosh Roy, C. J. Chien, C. Shang, Y. Ding, C. Yang, D. Mauri, Q. Leng, M. Pakala, M. Oogane, Y. Ando

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　356　73-81　2014/04

DOI： 10.1016/j.jmmm.2013.12.050 　

ISSN： 0304-8853

eISSN： 1873-4766
Abrupt Transition from Ferromagnetic to Antiferromagnetic of Interfacial Exchange in Perpendicularly Magnetized L1(0)- MnGa/FeCo Tuned by Fermi Level Position Peer-reviewed

Q. L. Ma, S. Mizukami, T. Kubota, X. M. Zhang, Y. Ando, T. Miyazaki

PHYSICAL REVIEW LETTERS　112　(15)　157202-1-157202-5　2014/04

DOI： 10.1103/PhysRevLett.112.157202 　

ISSN： 0031-9007

eISSN： 1079-7114
Development of Integrated Magnetic Tunnel Junctions for Detection of Bio-magnetic Field

Nishikawa Takuo, Oogane Mikihiko, Fujiwara Kousuke, Kato Daiki, Naganuma Hiroshi, Ando Yasuo

BME　52　O-503-O-503　2014
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.52.O-503 　

ISSN： 1347-443X

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Although the biomagnetic field is useful to observe an organic activity and the superconducting quantum interference device (SQUID) is used to detect at the moment, there is a problem of needing a liquid helium in order to operate this SQUID. This research focuses attention on the ferromagnetic tunnel junction (MTJ) device which is operable in a room temperature, and aims at the reduction of the elements for using this MTJ device as a biomagnetic field sensor and the reduction of the circuit system noise.
Fabrication of Magnetic Tunnel Junctions with Amorphous CoFeSiB for the Bio-magnetic Field Sensor Devices

Kato Daiki, Oogane Mikihiko, Fujiwara Kosuke, Nishikawa Takuo, Naganuma Hiroshi, Ando Yasuo

BME　52　O-504-O-504　2014
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.52.O-504 　

ISSN： 1347-443X

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In magnetic tunnel junctions (MTJs), the resistance changes by external magnetic field through tunnel magnetoresistance (TMR) effect and MTJs can be applied to magnetic field sensors. To detect a small bio-magnetic field, we have to develop MTJs with high sensitivity (=TMR/2H_k, H_k: magnetic anisotropy field) of more than 100%/Oe, which is two digit larger than that of actual devices. In this work, MTJs with a low H_k CoFeSiB amorphous electrode was fabricated to realize such a highly sensitive magnetic sensor. After optimizing the preparation condition of CoFeSiB, a very high sensitivity of 40%/Oe was obtained. The result came much closer to our goal.
Spin and symmetry properties of the buried Co2MnSi/MgO interface Peer-reviewed

R. Fetzer, Y. Ohdaira, H. Naganuma, M. Oogane, Y. Ando, T. Taira, T. Uemura, M. Yamamoto, M. Aeschlimann, M. Cinchetti

58th Annual Conf. on Magnetism and Magnetic Materials, Abstracts　624 (GB-14)　2013/11
Magnetic properties of L1(0)-Mn57Ga43/Co bilayer films with different Co thicknesses Peer-reviewed

R. Ranjbar, S. Mizukami, Y. Ando, T. Kubota, Q. L. Ma, X. M. Zhang, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　346　53-57　2013/11

DOI： 10.1016/j.jmmm.2013.07.008 　

ISSN： 0304-8853
Spintronics-based integrated circuits and contribution to energy saving society

Hideo Ohno, Takahiro Hanyu, Shoji Ikeda, Tetsuo Endoh, Yasuo Ando, Naoki Kasai

Journal of the Institute of Electronics, Information and Communication Engineers　96　(10)　771-775　2013/10

ISSN： 0913-5693
スピントロニクスを用いた集積回路と省エネ社会への貢献(<特別小特集>東北から明るい未来を創るICT技術) Peer-reviewed

大野英男, 遠藤哲郎, 羽生貴弘, 安藤康夫, 笠井直記, 池田正二

電子情報通信学会誌　96　(10)　771-775　2013/10/01
Fabrication of Magnetic Tunnel Junctions with Amorphous CoFeSiB Ferromagnetic Electrode for Magnetic Field Sensor Devices Peer-reviewed

Daiki Kato, Mikihiko Oogane, Kosuke Fujiwara, Takuo Nishikawa, Hiroshi Naganuma, Yasuo Ando

APPLIED PHYSICS EXPRESS　6　(10)　103004-1-103004-3　2013/10

DOI： 10.7567/APEX.6.103004 　

ISSN： 1882-0778

eISSN： 1882-0786
Tunneling magnetoresistance effect in MnGa based perpendicular magnetic tunnel junction with Fe/Co interlayer Peer-reviewed

Qinli Ma, Shigemi Mizukami, Takahide Kubota, Xianmin Zhang, Atsushi Sugihara, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　114　(16)　163913-1-163913-3　2013/10

DOI： 10.1063/1.4828483 　

ISSN： 0021-8979

eISSN： 1089-7550
The role of structure on magneto-transport properties of Heusler Co2MnSi films deposited on MgO(001) Peer-reviewed

N. Tal, D. Mogilyanski, A. Kovacs, H. Naganuma, S. Tsunegi, M. Oogane, Y. Ando, A. Kohn

JOURNAL OF APPLIED PHYSICS　114　(16)　163904-1-163904-10　2013/10

DOI： 10.1063/1.4826908 　

ISSN： 0021-8979

eISSN： 1089-7550
Interface state and coercivity in Nd-Fe-B/Dy films Peer-reviewed

Jin Umezawa, Yoshiki Sakai, Kunihiro Koike, Daisuke Ogawa, Yoshiyuki Mizuno, Hiroaki Kato, Takamichi Miyazaki, Yasuo Ando

JOURNAL OF THE KOREAN PHYSICAL SOCIETY　63　(3)　616-619　2013/08

DOI： 10.3938/jkps.63.616 　

ISSN： 0374-4884

eISSN： 1976-8524
Evaluation of interlayer exchange coupling in alpha-Fe(100)/Nd2Fe14B(001) films Peer-reviewed

Daisuke Ogawa, Kunihiro Koike, Hiroaki Kato, Shigemi Mizukami, Takamichi Miyazaki, Mikihiko Oogane, Yasuo Ando

JOURNAL OF THE KOREAN PHYSICAL SOCIETY　63　(3)　489-492　2013/08

DOI： 10.3938/jkps.63.489 　

ISSN： 0374-4884

eISSN： 1976-8524
Evaluation of interlayer exchange coupling in α-Fe(100)/Nd2Fe14B(001) Films Peer-reviewed

D. Ogawa, K. Koike, S. Mizukami, T. Miyazaki, M. Oogane, Y. Ando, H. Kato

J. Korean Phys. Soc.　63　(2)　0-0　2013/07
Effect of Annealing Temperature on Structure and Magnetic Properties of L1(0)-FePd/CoFeB Bilayer Peer-reviewed

M. N. I. Khan, H. Naganuma, N. Inami, M. Oogane, Y. Ando

IEEE TRANSACTIONS ON MAGNETICS　49　(7)　4409-4412　2013/07

DOI： 10.1109/TMAG.2013.2251612 　

ISSN： 0018-9464

eISSN： 1941-0069
Observation of Precessional Magnetization Dynamics in L1(0)-FePt Thin Films with Different L1(0) Order Parameter Values Peer-reviewed

Satoshi Iihama, Shigemi Mizukami, Nobuhito Inami, Takashi Hiratsuka, Gukcheon Kim, Hiroshi Naganuma, Mikihiko Oogane, Terunobu Miyazaki, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　52　(7)　073002-1-073002-4　2013/07

DOI： 10.7567/JJAP.52.073002 　

ISSN： 0021-4922

eISSN： 1347-4065
Fabrication of L1(0)-Ordered MnAl Films for Observation of Tunnel Magnetoresistance Effect Peer-reviewed

Haruaki Saruyama, Mikihiko Oogane, Yuta Kurimoto, Hiroshi Naganuma, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　52　(6)　063003-1-063003-4　2013/06

DOI： 10.7567/JJAP.52.063003 　

ISSN： 0021-4922

eISSN： 1347-4065
Magnetic and transport properties of tetragonal- or cubic-Heusler-type Co-substituted Mn-Ga epitaxial thin films Peer-reviewed

T. Kubota, S. Ouardi, S. Mizukami, G. H. Fecher, C. Felser, Y. Ando, T. Miyazaki

JOURNAL OF APPLIED PHYSICS　113　(17)　17C723　2013/05

DOI： 10.1063/1.4799143 　

ISSN： 0021-8979

eISSN： 1089-7550
Interface tailoring effect on magnetic properties and their utilization in MnGa-based perpendicular magnetic tunnel junctions Peer-reviewed

Q. L. Ma, T. Kubota, S. Mizukami, X. M. Zhang, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

PHYSICAL REVIEW B　87　(18)　184426-1-184426-18　2013/05

DOI： 10.1103/PhysRevB.87.184426 　

ISSN： 1098-0121
Detection of sub-nano-tesla magnetic field by integrated magnetic tunnel junctions with bottom synthetic antiferro-coupled free layer Peer-reviewed

Kosuke Fujiwara, Mikihiko Oogane, Takuo Nishikawa, Hiroshi Naganuma, Yasuo Ando

Japanese Journal of Applied Physics　52　(4)　04CM07-1-04CM07-4　2013/04

DOI： 10.7567/JJAP.52.04CM07 　

ISSN： 0021-4922 1347-4065
Magnetic tunnel junctions of perpendicularly magnetized L1(0)-MnGa/Fe/MgO/CoFe structures: Fe-layer-thickness dependences of magnetoresistance effect and tunnelling conductance spectra Peer-reviewed

T. Kubota, Q. L. Ma, S. Mizukami, X. M. Zhang, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF PHYSICS D-APPLIED PHYSICS　46　(15)　155001　2013/04

DOI： 10.1088/0022-3727/46/15/155001 　

ISSN： 0022-3727

eISSN： 1361-6463
Structural and magnetic properties of L10-FePd/MgO films on GaAs and InP lattice mismatched substrates Peer-reviewed

M. Kohda, S. Iimori, R. Ohsugi, H. Naganuma, T. Miyazaki, Y. Ando, J. Nitta

Applied Physics Letters　102　(10)　102411　2013/03/11

DOI： 10.1063/1.4795443 　

ISSN： 0003-6951
Nonlinear Emission of Spin-Wave Caustics from an Edge Mode of a Microstructured Co2Mn0.6Fe0.4Si Waveguide Peer-reviewed

T. Sebastian, T. Braecher, P. Pirro, A. A. Serga, B. Hillebrands, T. Kubota, H. Naganuma, M. Oogane, Y. Ando

PHYSICAL REVIEW LETTERS　110　(6)　067201-1-067201-5　2013/02

DOI： 10.1103/PhysRevLett.110.067201 　

ISSN： 0031-9007
Tunnel magnetoresistance effect in tunnel junctions with Co2MnSi heusler alloy electrode and MgO barrier Peer-reviewed

Yasuo Ando, Sumito Tsunegi, Mikihiko Oogane, Hiroshi Naganuma, Koki Takanashi

Spintronics: From Materials to Devices　355-366　2013/01/01
Publisher: Springer Netherlands
DOI： 10.1007/978-90-481-3832-6_17 　
Magnetoresistance enhancement in MnxGa 100 - X/MgO/CoFeB perpendicular magnetic tunnel junctions by using CoFeB interlayer Peer-reviewed

Q. L. Ma, T. Kubota, S. Mizukami, X. M. Zhang, M. Oogane, H. Naganuma, Y. Ando, T. Miyazaki

IEEE Transactions on Magnetics　49　(7)　4339-4342　2013

DOI： 10.1109/TMAG.2013.2242861 　

ISSN： 0018-9464
Observation of a large spin-dependent transport length in organic Spin valves at room temperature Peer-reviewed

Xianmin Zhang, Shigemi Mizukami, Takahide Kubota, Qinli Ma, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

Nature Communications　4　1392　2013

DOI： 10.1038/ncomms2423 　

ISSN： 2041-1723
Magnetic Properties of Single Crystalline Co2MnAl Heusler Alloy Thin Films Peer-reviewed

Yilgin Resul, Sakuraba Yuya, Oogane Mikihiko, Ando Yasuo, Miyazaki Terunobu

JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM　25　(8)　2659-2663　2012/12

DOI： 10.1007/s10948-011-1238-x 　

ISSN： 1557-1939
Magnetic Properties andMagnetic Domain Structures Evolution Modulated by CoFeB Layer in [Pd/Co]/CoFeB/MgO/CoFeB/[Co/Pd] Perpendicular MTJ Films Peer-reviewed

Tian Yu, Hiroshi Naganuma, D. W. Shi, Yasuo Ando, X. F. Han

IEEE Transactions on Magnetics　48　2812-2815　2012/10/19

DOI： 10.1109/TMAG.2012.2198795 　
EVALUATION OF EXCHANGE COUPLING IN Nd2Fe14B/α-Fe INTERFACES

D. Ogawa, K. Koike, S. Mizukami, T. Miyazaki, M. Oogane, Y. Ando, H. Kato

Proceedings on 21st Workshop on Rare-Earth Permanent Magnets and their Applications (REPM'12)　2012/09/02
COERCIVITY ENHANCEMENT PHENOMENA OBSERVED IN VARIOUS SERIES OF Nd2Fe14B/Nd FILMS

K. Koike, T. Kusano, D. Ogawa, Y. Mizuno, T. Miyazaki, Y. Ando, H. Kato

Proceedings on 21st Workshop on Rare-Earth Permanent Magnets and their Applications (REPM'12)　2012/09/02
Effect of Mg interlayer on perpendicular magnetic anisotropy of CoFeB films in MgO/Mg/CoFeB/Ta structure Peer-reviewed

Q. L. Ma, S. Iihama, T. Kubota, X. M. Zhang, S. Mizukami, Y. Ando, T. Miyazaki

APPLIED PHYSICS LETTERS　101　(12)　122414　2012/09

DOI： 10.1063/1.4754118 　

ISSN： 0003-6951
Enhancement of magnetoresistance using CoFe/Ru/CoFe synthetic ferrimagnetic pinned layer in BiFeO3 based spin-valves Peer-reviewed

Hiroshi Naganuma, In-Tae Bae, Takamichi Miyazaki, Miho Kubota, Nobuhito Inami, Yuki Kawada, Mikihiko Oogane, Shigemi Mizukami, X. F. Han, Yasuo Ando

APPLIED PHYSICS LETTERS　101　(7)　072901-1-072901-3　2012/08

DOI： 10.1063/1.4745504 　

ISSN： 0003-6951
Damping of Magnetization Precession in Perpendicularly Magnetized CoFeB Alloy Thin Films Peer-reviewed

Satoshi Iihama, Qinli Ma, Takahide Kubota, Shigemi Mizukami, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS EXPRESS　5　(8)　083001　2012/08

DOI： 10.1143/APEX.5.083001 　

ISSN： 1882-0778
Magnetoresistance effect in L1(0)-MnGa/MgO/CoFeB perpendicular magnetic tunnel junctions with Co interlayer Peer-reviewed

Q. L. Ma, T. Kubota, S. Mizukami, X. M. Zhang, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

APPLIED PHYSICS LETTERS　101　(3)　032402-1-032402-3　2012/07

DOI： 10.1063/1.4737000 　

ISSN： 0003-6951
Nd2Fe14B/α-Fe界面における交換結合の評価

小川大介, 小池邦博, 水上成美, 大兼幹彦, 安藤康夫, 宮崎孝道, 加藤宏朗

信学技報　2012/06/14
Observation of magnetic moments at the interface region in magnetic tunnel junctions using depth-resolved x-ray magnetic circular dichroism Peer-reviewed

S. Tsunegi, Y. Sakuraba, K. Amemiya, M. Sakamaki, E. Ozawa, A. Sakuma, K. Takanashi, Y. Ando

Phys. Rev. B　85　180408-1-180408-4　2012/05

DOI： 10.1103/PhysRevB.85.180408 　
Annealing Temperature and Co Layer Thickness Dependence of Magnetoresistance Effect for -MnGa/Co/MgO/CoFeB Perpendicular Magnetic Tunnel Junctions Peer-reviewed

Q. L. Ma, Takahide Kubota, Shigemi Mizukami, X. M. Zhang, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

IEEE Transactions on Magnetics　48　2808-2811　2012/04/16

DOI： 10.1109/TMAG.2012.2196420 　
Electrical manipulation of spin polarization and generation of giant spin current using multi terminal spin injectors Peer-reviewed

S. Nonoguchi, T. Nomura, Y. Ando, T. Kimura

JOURNAL OF APPLIED PHYSICS　111　(7)　2012/04

DOI： 10.1063/1.3672245 　

ISSN： 0021-8979

eISSN： 1089-7550
Fabrication of L1(0)-MnAl perpendicularly magnetized thin films for perpendicular magnetic tunnel junctions Peer-reviewed

Masaki Hosoda, Mikihiko Oogane, Miho Kubota, Takahide Kubota, Haruaki Saruyama, Satoshi Iihama, Hiroshi Naganuma, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　111　(7)　07A324-1-07A324-3　2012/04

DOI： 10.1063/1.3676428 　

ISSN： 0021-8979

eISSN： 1089-7550
Promotion of L1(0) ordering of FePd films with amorphous CoFeB thin interlayer Peer-reviewed

M. N. I. Khan, N. Inami, H. Naganuma, Y. Ohdaira, M. Oogane, Y. Ando

JOURNAL OF APPLIED PHYSICS　111　(7)　07C112-1-07C112-3　2012/04

DOI： 10.1063/1.3673409 　

ISSN： 0021-8979

eISSN： 1089-7550
Dependence of Tunnel Magnetoresistance Effect on Fe Thickness of Perpendicularly Magnetized L1(0)-Mn62Ga38/Fe/MgO/CoFe Junctions Peer-reviewed

Takahide Kubota, Qinli Ma, Shigemi Mizukami, Xianmin Zhang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS EXPRESS　5　(4)　043003-1-043003-3　2012/04

DOI： 10.1143/APEX.5.043003 　

ISSN： 1882-0778

eISSN： 1882-0786
Fabrication of magnetic tunnel junctions with a bottom synthetic antiferro-coupled free layers for high sensitive magnetic field sensor devices Peer-reviewed

Kosuke Fujiwara, Mikihiko Oogane, Saeko Yokota, Takuo Nishikawa, Hiroshi Naganuma, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　111　(7)　07C710-1-07C710-3　2012/04

DOI： 10.1063/1.3677266 　

ISSN： 0021-8979

eISSN： 1089-7550
Dependence of spin-transfer switching characteristics in magnetic tunnel junctions with synthetic free layers on coupling strength Peer-reviewed

Masayuki Nishimura, Mikihiko Oogane, Hiroshi Naganuma, Nobuhito Inami, Tadashi Morita, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　111　(7)　07C905-1-07C905-3　2012/04

DOI： 10.1063/1.3672240 　

ISSN： 0021-8979

eISSN： 1089-7550
Large change of perpendicular magnetic anisotropy in Cobalt ultrathin film induced by varying capping layers Peer-reviewed

Xianmin Zhang, Shigemi Mizukami, Takahide Kubota, Qinli Ma, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　111　(7)　07B320-1-07B320-3　2012/04

DOI： 10.1063/1.3676240 　

ISSN： 0021-8979

eISSN： 1089-7550
Annealing temperature dependence of exchange bias in BiFeO3/CoFe bilayers Peer-reviewed

T. Yu, H. Naganuma, W. X. Wang, Y. Ando, X. F. Han

JOURNAL OF APPLIED PHYSICS　111　(7)　07D908-1-07D908-3　2012/04

DOI： 10.1063/1.3673435 　

ISSN： 0021-8979

eISSN： 1089-7550
Low-damping spin-wave propagation in a micro-structured Co2Mn0.6Fe0.4Si Heusler waveguide Peer-reviewed

T. Sebastian, Y. Ohdaira, T. Kubota, P. Pirro, T. Braecher, K. Vogt, A. A. Serga, H. Naganuma, M. Oogane, Y. Ando, B. Hillebrands

APPLIED PHYSICS LETTERS　100　(11)　112402-1-112402-3　2012/03

DOI： 10.1063/1.3693391 　

ISSN： 0003-6951
Evaluation of Exchange Coupling in α-Fe(100)/Nd2Fe14B(001) Interface Peer-reviewed

D. Ogawa, K. Koike, N. Mizukami, K. Oogane, Y. Ando, T. Miyazaki, H. Kato

Journal of magnetics society of Japan　36　(1)　5-12　2012/01
Composition dependence of magnetic properties in perpendicularly magnetized epitaxial thin films of Mn-Ga alloys Peer-reviewed

S. Mizukami, T. Kubota, F. Wu, X. Zhang, T. Miyazaki, H. Naganuma, M. Oogane, A. Sakuma, Y. Ando

PHYSICAL REVIEW B　85　(1)　014416-1-014416-6　2012/01

DOI： 10.1103/PhysRevB.85.014416 　

ISSN： 1098-0121
The magnetic and structural properties of Co2MnSi Heusler alloy thin films on the orientation of Ge substrate Peer-reviewed

M. A. I. Nahid, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

Phys. Status Solidi A　208　675-378　2011/12/06

DOI： 10.1002/pssa.201026569 　
Composition dependence of magnetoresistance effect and its annealing endurance in tunnel junctions having Mn-Ga electrode with high perpendicular magnetic anisotropy Peer-reviewed

Takahide Kubota, Masaaki Araidai, Shigemi Mizukami, Xianmin Zhang, Qinli Ma, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Masaru Tsukada, Terunobu Miyazaki

APPLIED PHYSICS LETTERS　99　(19)　192509-1-192509-3　2011/11

DOI： 10.1063/1.3659484 　

ISSN： 0003-6951

eISSN： 1077-3118
Large Magnetoresistance Effect in Epitaxial Co2Fe0.4Mn0.6Si/Ag/Co2Fe0.4Mn0.6Si Devices Peer-reviewed

Jo Sato, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

APPLIED PHYSICS EXPRESS　4　(11)　113005-1-113005-3　2011/11

DOI： 10.1143/APEX.4.113005 　

ISSN： 1882-0778

eISSN： 1882-0786
Transport Properties of Pure Spin Currents in a Polycrystalline Gd Wire Peer-reviewed

S. Nonoguchi, Y. Ando, S. Yakata, T. Kimura

IEEE TRANSACTIONS ON MAGNETICS　47　(10)　2750-2752　2011/10

DOI： 10.1109/TMAG.2011.2158407 　

ISSN： 0018-9464
Interface effects on perpendicular magnetic anisotropy for molecular-capped cobalt ultrathin films Peer-reviewed

Xianmin Zhang, Shigemi Mizukami, Takahide Kubota, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS LETTERS　99　(16)　162509-1-162509-3　2011/10

DOI： 10.1063/1.3651766 　

ISSN： 0003-6951
Time-Resolved Kerr Effect in Very Thin Films of CoCrPt Alloys Peer-reviewed

Shigemi Mizukami, Daisuke Watanabe, Takahide Kubota, X. Zhang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, T. Miyazaki

IEEE Transaction on Magnetics　47　(10)　3897-38900　2011/09/23

DOI： 10.1109/TMAG.2011.2154357 　
Spin Transport in Co/Al2O3 Alq3 Co Organic Spin Valve Peer-reviewed

Xianmin Zhang, Shigemi Mizukami, Takahide Kubota???, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

IEEE TRANSACTIONS ON MAGNETICS　47　(10)　2649-2651　2011/09
Spin transistor using magnetic tunnel junctions with half-metallic Co2MnSi Heusler alloy electrodes Peer-reviewed

Y. Ohdaira, M. Oogane, H. Naganuma, Y. Ando

APPLIED PHYSICS LETTERS　99　(13)　132513-1-132513-3　2011/09

DOI： 10.1063/1.3645637 　

ISSN： 0003-6951

eISSN： 1077-3118
Quadratic magneto-optical Kerr effect in Co2MnSi Peer-reviewed

Georg Wolf, Jaroslav Hamrle, Simon Trudel, Takahide Kubota, Yasuo Ando, Burkard Hillebrands

JOURNAL OF APPLIED PHYSICS　110　(4)　043904-1-043904-5　2011/08

DOI： 10.1063/1.3622512 　

ISSN： 0021-8979
Fabrication of MgO-based magnetic tunnel junctions for subnanosecond spin transfer switching Peer-reviewed

Tatsuya Aoki, Yasuo Ando, Mikihiko Oogane, Hiroshi Naganuma

Journal of Physics: conference serise　266　012086　2011/07

DOI： 10.1088/1742-6596/266/1/012086 　
The perpendicular anisotropy of Co40Fe40B20 sandwiched between Ta and MgO layers and its application in CoFeB/MgO/CoFeB tunnel junction Peer-reviewed

W. X. Wang, Y. Yang, H. Naganuma, Y. Ando, R. C. Yu, X. F. Han

APPLIED PHYSICS LETTERS　99　(1)　012502-1-012502-3　2011/07

DOI： 10.1063/1.3605564 　

ISSN： 0003-6951

eISSN： 1077-3118
Effect of metallic Mg insertion on the magnetoresistance effect in MgO-based tunnel junctions using D0(22)-Mn3-delta Ga perpendicularly magnetized spin polarizer Peer-reviewed

Takahide Kubota, Shigemi Mizukami, Daisuke Watanabe, Feng Wu, Xianmin Zhang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　110　(1)　013915-1-013915-5　2011/07

DOI： 10.1063/1.3603034 　

ISSN： 0021-8979
Fabrication of Multiferroic Co-Substituted BiFeO3 Epitaxial Films on SrTiO3 (100) Substrates by Radio Frequency Magnetron Sputtering Peer-reviewed

Husne Ara Begum, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

Materials　4　1087-1095　2011/06/09

DOI： 10.3390/ma4061087 　
The effect of film and interface structure on the transport properties of Heusler based current-perpendicular-to-plane spin valves Peer-reviewed

V. K. Lazarov, K. Yoshida, J. Sato, P. J. Hasnip, M. Oogane, A. Hirohata, Y. Ando

APPLIED PHYSICS LETTERS　98　(24)　242508-1-242508-3　2011/06

DOI： 10.1063/1.3600792 　

ISSN： 0003-6951

eISSN： 1077-3118
Magnetoresistance Effect in Tunnel Junctions with Perpendicularly Magnetized D0(22)-Mn3-delta Ga Electrode and MgO Barrier Peer-reviewed

Takahide Kubota, Yoshio Miura, Daisuke Watanabe, Shigemi Mizukami, Feng Wu, Hiroshi Naganuma, Xianmin Zhang, Mikihiko Oogane, Masafumi Shirai, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS EXPRESS　4　(4)　043002-1-043002-3　2011/04

DOI： 10.1143/APEX.4.043002 　

ISSN： 1882-0778
Exchange biases of Co, Py, Co40Fe40B20, Co75Fe25, and Co50Fe50 on epitaxial BiFeO3 films prepared by chemical solution deposition Peer-reviewed

Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　109　(7)　07D736-1-07D736-3　2011/04

DOI： 10.1063/1.3563061 　

ISSN： 0021-8979
Long-Lived Ultrafast Spin Precession in Manganese Alloys Films with a Large Perpendicular Magnetic Anisotropy Peer-reviewed

S. Mizukami, F. Wu, A. Sakuma, J. Walowski, D. Watanabe, T. Kubota, X. Zhang, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

PHYSICAL REVIEW LETTERS　106　(11)　117201-1-117201-4　2011/03

DOI： 10.1103/PhysRevLett.106.117201 　

ISSN： 0031-9007
Pressure-induced half-metallic gap transformation in Co2MnSi observed by tunneling conductance spectroscopy Peer-reviewed

M. Nobori, T. Nakano, J. Hasegawa, G. Oomi, Y. Sakuraba, K. Takanashi, Y. Miura, Y. Ohdaira, Y. Ando

PHYSICAL REVIEW B　83　(10)　104410-1-104410-6　2011/03

DOI： 10.1103/PhysRevB.83.104410 　

ISSN： 2469-9950

eISSN： 2469-9969
The effect of inserting thin Co2MnAl layer into the Co2MnSi/MgO interface on tunnel magnetoresistance effect Peer-reviewed

E. Ozawa, S. Tsunegi, M. Oogane, H. Naganuma, Y. Ando

Journal ofPhysics:ConferenceSeries　266　012104-1-012104-4　2011/01/28

DOI： 10.1088/1742-6596/266/1/012104 　
Magnetoresistance Effect in Co2MnSi/semimetallic-Fe2VAl/CoFe Junctions Peer-reviewed

T Kubota, M Oogane, S Mizukami, H Naganuma, Y Ando, T Miyazaki

Journal ofPhysics:ConferenceSeries　266　012096-1-012096-5　2011/01/28

DOI： 10.1088/1742-6596/266/1/012096 　
Influence of composition on structure and magnetic properties of epitaxial Mn-Ga films Peer-reviewed

F Wu, S Mizukami, D Watanabe, H Naganuma, M Oogane, Y Ando, T Miyazaki

Journal of Physics: Conference Series　266　012112-1-012112-5　2011/01/28

DOI： 10.1088/1742-6596/266/1/012112 　
Laser-induced fast magnetization precession and Gilbert damping for CoCrPt alloy thin films with perpendicular magnetic anisotropy Peer-reviewed

Shigemi Mizukami, Daisuke Watanabe, Takahide Kubota, Xianmin Zhang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

Applied physics express　3　123001-1-123001-3　2011
Gilbert Damping in Ni/Co Multilayer Films Exhibiting Large Perpendicular Anisotropy Peer-reviewed

Shigemi Mizukami, Xianmin Zhang, Takahide Kubota, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

Applied Physics Express 4 (2011) 013005　4　(1)　13005-013005-3　2011
Publisher: The Japan Society of Applied Physics
DOI： 10.1143/APEX.4.013005 　

ISSN： 1882-0778

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Gilbert damping is reported in perpendicularly magnetized Ni/Co multilayer films with Pt buffer and capping layers, and investigated through the time-resolved magneto-optical Kerr effect under various applied magnetic field strengths and directions. Both damping constant $\alpha$ and perpendicular magnetic anisotropy energy $K_{\text{u } }$ depend strongly on layer thickness and bilayer periodicity, and rise to approximately 0.08 and 8 Merg/cm3, respectively. The Gilbert damping rate depends linearly on inverse multilayer thickness, indicating that large damping in the Ni/Co multilayers stems from its interfaces in contact with the Pt layers.
Influence of Pt Doping on Gilbert Damping in Permalloy Films and Comparison with the Perpendicularly Magnetized Alloy Films Peer-reviewed

Shigemi Mizukami, Takahide Kubota, Xianmin Zhang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

Japanese Journal of Applied Physics 50 (2011) 103003　50　(10)　103003-103003-5　2011
Publisher: The Japan Society of Applied Physics
DOI： 10.1143/JJAP.50.103003 　

ISSN： 0021-4922

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Effects of Pt doping on magnetic properties and Gilbert damping are investigated for Ni80Fe20 permalloy films to compare with damping in alloy films containing Pt with a large perpendicular anisotropy. Gilbert damping constant \alpha and g-factor g for (Ni80Fe20)100-xPtx (x = 0{\mbox{-- } }34 at. %) are evaluated from out-of-plane angular variations of ferromagnetic resonance (FMR) linewidth and resonance field with an analysis based on the Landau--Lifshitz--Gilbert equation. Data of angular dependence of the FMR linewidth are fitted reasonably well by a theoretical model without having to take into account any extrinsic influences on linewidth, thereby allowing us to determine precise values of \alpha. The \alpha values show variation with increasing Pt concentration rising by {\sim}0.06 at a Pt concentration of 34 at. %, which is very close to those in perpendicularly magnetized CoCrPt and FePt film reported recently. Nevertheless, Gilbert damping rate G for the Pt doped permalloy films is smaller than those in CoCrPt and FePt films. These experimental results are discussed with a spin--orbit torque theory.
Fast magnetization precession observed in L1(0)-FePt epitaxial thin film Peer-reviewed

S. Mizukami, S. Iihama, N. Inami, T. Hiratsuka, G. Kim, H. Naganuma, M. Oogane, Y. Ando

APPLIED PHYSICS LETTERS　98　(5)　052501-1-052501-3　2011/01

DOI： 10.1063/1.3549704 　

ISSN： 0003-6951

eISSN： 1077-3118
Fabrication of Magnetic Tunnel Junctions with a Synthetic Ferrimagnetic Free Layer for Magnetic Field Sensor Applications Peer-reviewed

Kousuke Fujiwara, Mikihiko Oogane, Futoyoshi Kou, Daisuke Watanabe, Hiroshi Naganuma, Yasuo Ando

JAPANESE JOURNAL OF APPLIED PHYSICS　50　(1)　013001-1-013001-3　2011/01

DOI： 10.1143/JJAP.50.013001 　

ISSN： 0021-4922
Retraction: ‘‘Large Tunnel Magnetoresistance of 1056% at Room Temperature in MgO Based Double Barrier Magnetic Tunnel Junction’’ [Appl. Phys. Express 2 (2009) 083002] Peer-reviewed

Hiroshi Naganuma, Lixian Jiang, Mikihiko Oogane, Yasuo Ando

Applied Physics Express　4　(1)　019201-019201　2010/12/16
Publisher: The Japan Society of Applied Physics
DOI： 10.1143/APEX.4.019201 　

ISSN： 1882-0778
Band-Structure-Dependent Demagnetization in the Heusler Alloy Co2Mn1-xFexSi Peer-reviewed

Daniel Steil, Sabine Alebrand, Tobias Roth, Michael Krauss, Takahide Kubota, Mikihiko Oogane, Yasuo Ando, Hans Christian Schneider, Martin Aeschlimann, Mirko Cinchetti

PHYSICAL REVIEW LETTERS　105　(21)　217202-1-217202-4　2010/11

DOI： 10.1103/PhysRevLett.105.217202 　

ISSN： 0031-9007
Ferromagnetic resonance investigation of exchange coupling in Nd2Fe14B/α-Fe interfaces

D. Ogawa, K. Koike, T. Miyazaki, S. Mizukami, T. Akiya, M. Oogane, Y. Ando, H. Kato

Proc. on the 21th International Workshop on Rare-earth Permanent Magnets and their Applications　2010/08/28
Structural characterization of epitaxial multiferroic BiFeO3 films grown on SrTiO3 (100) substrates by crystallizing amorphous Bi-Fe-O-x Peer-reviewed

Hiroshi Naganuma, Takamichi Miyazaki, Akihiko Ukachi, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN　118　(1380)　648-651　2010/08

DOI： 10.2109/jcersj2.118.648 　

ISSN： 1882-0743

eISSN： 1348-6535
Gilbert magnetic damping constant of epitaxially grown Co-based Heusler alloy thin films Peer-reviewed

M. Oogane, T. Kubota, Y. Kota, S. Mizukami, H. Naganuma, A. Sakuma, Y. Ando

APPLIED PHYSICS LETTERS　96　(25)　252501-1-252501-3　2010/06

DOI： 10.1063/1.3456378 　

ISSN： 0003-6951

eISSN： 1077-3118
Structural and Magnetic Properties of Perpendicular Magnetized Mn2.5Ga Epitaxial Films Peer-reviewed

F. Wu, S. Mizukami, D. Watanabe, E. P. Sajitha, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

IEEE TRANSACTIONS ON MAGNETICS　46　(6)　1863-1865　2010/06

DOI： 10.1109/TMAG.2010.2045108 　

ISSN： 0018-9464
Fabrication of perpendicularly magnetized magnetic tunnel junctions with [formula omitted] hybrid electrode Peer-reviewed

T. Hiratsuka, G. Kim, Y. Sakuraba, T. Kubota, K. Kodama, N. Inami, H. Naganuma, M. Oogane, T. Nakamura, K. Takanashi, Y. Ando

Journal of Applied Physics　107　(9)　2010/05/01

DOI： 10.1063/1.3358239 　

ISSN： 1089-7550 0021-8979

eISSN： 1089-7550
Fabrication of perpendicularly magnetized magnetic tunnel junctions with L1(0)-CoPt/Co2MnSi hybrid electrode Peer-reviewed

T. Hiratsuka, G. Kim, Y. Sakuraba, T. Kubota, K. Kodama, N. Inami, H. Naganuma, M. Oogane, T. Nakamura, K. Takanashi, Y. Ando

JOURNAL OF APPLIED PHYSICS　107　(9)　09C714-1-09C714-3　2010/05

DOI： 10.1063/1.3358239 　

ISSN： 0021-8979

eISSN： 1089-7550
Reproducible trajectory on subnanosecond spin-torque magnetization switching under a zero-bias field for MgO-based ferromagnetic tunnel junctions Peer-reviewed

Tatsuya Aoki, Yasuo Ando, Mikihiko Oogane, Hiroshi Naganuma

APPLIED PHYSICS LETTERS　96　(14)　142502-1-142502-3　2010/04

DOI： 10.1063/1.3380595 　

ISSN： 0003-6951
Gilbert damping in perpendicularly magnetized Pt/Co/Pt films investigated by all-optical pump-probe technique Peer-reviewed

S. Mizukami, E. P. Sajitha, D. Watanabe, F. Wu, T. Miyazaki, H. Naganuma, M. Oogane, Y. Ando

APPLIED PHYSICS LETTERS　96　(15)　152502-1-152502-3　2010/04

DOI： 10.1063/1.3396983 　

ISSN： 0003-6951
Evidence of Fermi level control in a half-metallic Heusler compound Co2MnSi by Al-doping: Comparison of measurements with first-principles calculations Peer-reviewed

Y. Sakuraba, K. Takanashi, Y. Kota, T. Kubota, M. Oogane, A. Sakuma, Y. Ando

PHYSICAL REVIEW B　81　(14)　144422-1-144422-5　2010/04

DOI： 10.1103/PhysRevB.81.144422 　

ISSN： 2469-9950

eISSN： 2469-9969
Epitaxial growth of Co2MnSi thin films at the vicinal surface of n-Ge(111) substrate Peer-reviewed

M. A. I. Nahid, M. Oogane, H. Naganuma, Y. Ando

APPLIED PHYSICS LETTERS　96　(14)　142501-1-142501-3　2010/04

DOI： 10.1063/1.3378986 　

ISSN： 0003-6951
Element-Specific Evaluation of Magnetic Moments in Ferrimagnetic Magnetic Mn₂Val Heusler Epitaxial Thin Films Peer-reviewed

K. Kodama, T. Nakamura, Y. Sakuraba, M. Oogane, H. Naganuma, K. Takanashi, Y, Ando

J. Magn. Soc. Jpn.　34　(2)　100-106　2010/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1002R0004 　

ISSN： 1882-2924

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We successfully fabricated L2₁-ordered Mn₂VAl Heusler thin films and evaluated their ferrimagnetic properties by soft x-ray magnetic circular dichroism (XMCD). The buffer layers and annealing temperatures were varied to prepare the Mn₂VAl films. We discovered that Mn₂VAl could be ordered in an L2₁ phase well when it was deposited directly onto an MgO (001) single crystalline substrate. The maximum values of L2₁ and B2 long-range order parameters we obtained were about 0.5 for both phases for samples without a buffer layer, when substrates were heated at 500°C or 600°C. The saturation magnetization (M_s) for these samples was roughly 150 emu/cc. This is rather small compared to that expected from the ideal Slater-Pauling behavior, which might be due to the suppressed degree of L2₁ or B2 ordering. Ferrimagnetism in the Mn₂VAl, ferrimagnetic coupling between Mn and V moments was clearly observed by using the XMCD technique in well-ordered L2₁-Mn₂VAl film as has been predicted in theoretical investigations.
Magnetoresistance and Structure of MgO-Based Magnetic Tunnel Junctions with Perpendicularly Magnetized L10-FePt Peer-reviewed

永沼博, 平塚喬士, 金国天, 宮﨑孝道, 佐藤和久, 今野豊彦, 大兼幹彦, 安藤康夫

日本磁気学会誌　34　(3)　293-296　2010/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.1003R047 　

ISSN： 1882-2924

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Perpendicularly magnetized magnetic tunnel junctions (MTJs) were fabricated by depositing thin L1₀-ordered FePt films on MgO(001) substrates using a UHV sputtering system, and the dependence of structural, magnetic, and magnetotransport properties of the junctions on the thickness of the FePt layers was investigated. A full epitaxial structure of MgO(001) sub./Cr/Pt/FePt/MgO/CoPt/Ta was observed. The tunnel magnetoresistance (TMR) ratio was measured to be 6% at room temperature, and magnetization switching was clearly observed in the thin FePt layer. Transmission electron microscopy (TEM) observations revealed that the interface between FePt, MgO, and CoPt layer has strain due to lattice mismatch, which might be a reason for the low TMR ratio.
Investigation of spin-dependent transport properties and spin-spin interactions in a CuPc-Co nano-composite system Peer-reviewed

Z.Tang, S.Tanabe, D.Hatanaka, T.Nozaki, T.Shinjo, S.Mizukami, Y.Ando, Y.Suzuki, M.Shiraishi

Japanese Journal of Applied Physics　Vol.49,　133002-1-4　2010/03

DOI： 10.1143/JJAP.49.033002 　
Optically induced magnetization dynamics and variation of damping parameter in epitaxial Co2MnSi Heusler alloy films Peer-reviewed

Y. Liu, L. R. Shelford, V. V. Kruglyak, R. J. Hicken, Y. Sakuraba, M. Oogane, Y. Ando

PHYSICAL REVIEW B　81　(9)　094402-1-094402-12　2010/03

DOI： 10.1103/PhysRevB.81.094402 　

ISSN： 2469-9950

eISSN： 2469-9969
Co-concentration dependence of half-metallic properties in Co-Mn-Si epitaxial films Peer-reviewed

Y. Sakuraba, N. Hirose, M. Oogane, T. Nakamura, Y. Ando, K. Takanashi

APPLIED PHYSICS LETTERS　96　(9)　092511-1-092511-3　2010/03

DOI： 10.1063/1.3330942 　

ISSN： 0003-6951

eISSN： 1077-3118
Note: Probing quadratic magneto-optical Kerr effects with a dual-beam system Peer-reviewed

Simon Trudel, Georg Wolf, Helmut Schultheiss, Jaroslav Hamrle, Burkard Hillebrands, Takahide Kubota, Yasuo Ando

REVIEW OF SCIENTIFIC INSTRUMENTS　81　(2)　026105-1-026105-3　2010/02

DOI： 10.1063/1.3276715 　

ISSN： 0034-6748
Optimization of interface condition for efficient spin injection in Permalloy/Cu lateral spin valve Peer-reviewed

S. Yakata, Y. Ando, T. Kimura

TENCON 2010: 2010 IEEE REGION 10 CONFERENCE　126-128　2010

DOI： 10.1109/TENCON.2010.5685852 　

ISSN： 0886-1420
Synthetic CoFeB/Ru/NiFe free layer on MgO barrier layer for spin transfer switching Peer-reviewed

Takuya Ono, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

J. Phys.: Conf. Ser.　2010

DOI： 10.1088/1742-6596/200/6/062019 　
Spin transistor based on double tunnel junctions using half-metallic Co2MnSi electrodes Peer-reviewed

Yusuke Ohdaira, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

J. Phys.: Conf. Ser.　2010

DOI： 10.1088/1742-6596/200/5/052019 　
Dynamic Magnetic Intermediate State during Nanosecond Spin Transfer Switching for MgO-Based Magnetic Tunnel Junctions Peer-reviewed

Tatsuya Aoki, Yasuo Ando, Mikihiko Oogane, Hiroshi Naganuma

Applied Physics Express　3　(5)　53002-053002-3　2010
Publisher: The Japan Society of Applied Physics
DOI： 10.1143/APEX.3.053002 　

ISSN： 1882-0778

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We report for the first time that the dynamic magnetic intermediate state (DMI) was observed at a speed of several ns during spin transfer switching for MgO-based magnetic tunnel junctions (MTJs). The DMI was observed as slow resistance oscillation at the center of the parallel to anti-parallel state by single shot time domain measurements. The DMI is observable at certain current amplitudes. The outbreak probability decreases with further current increase. We concluded that the DMI originates from inhomogeneous magnetization behavior. On the other hand, previous single shot time domain measurements have shown only for single-domain-like magnetization behavior.
Magnetization Dynamics in CoFeB Buffered Perpendicularly Magnetized Co/Pd Multilayer Peer-reviewed

Sajitha, E.P, Walowski, J, Watanabe, D, Mizukami, S, Feng Wu, Naganuma, H, Oogane, M, Ando, Y, Miyazaki, T

IEEE Transactions on Magnetics　2010

DOI： 10.1109/TMAG.2009.2038929 　
The Effect of Doping Concentration of Si on the Nature of Barrier of CoMnSi/MgO/n-Si Junctions Peer-reviewed

Nahid, M.A.I, Oogane, M, Naganuma, H, Ando, Y

IEEE Transactions on Magnetics　2010

DOI： 10.1109/TMAG.2010.2043223 　
Spin-transfer Switching in Magnetic Tunnel Junctions with Synthetic Ferri-magnetic Free Layer Peer-reviewed

M. Nishimura, M. Oogane, H. Naganuma, N. Inami, S. Ikeda, H. Ohno, Y. Ando

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　052018-1-052018-4　2010

DOI： 10.1088/1742-6596/200/5/052018 　

ISSN： 1742-6588
High efficient spin transfer torque writing on perpendicular magnetic tunnel junctions for high density MRAMs Peer-reviewed

Hiroaki Yoda, Tatsuya Kishi, Toshihiko Nagase, Masatoshi Yoshikawa, Katsuya Nishiyama, Eiji Kitagawa, Tadaomi Daibou, Minoru Amano, Naoharu Shimomura, Shigeki Takahashi, Tadashi Kai, Masahiko Nakayama, Hisanori Aikawa, Sumio Ikegawa, Makoto Nagamine, Junichi Ozeki, Shigemi Mizukami, Mikihiko Oogane, Yasuo Ando, Shinji Yuasa, Kei Yakushiji, Hitoshi Kubota, Yoshishige Suzuki, Yoshinobu Nakatani, Terunobu Miyazaki, Koji Ando

CURRENT APPLIED PHYSICS　10　(1)　E87-E89　2010/01

DOI： 10.1016/j.cap.2009.12.021 　

ISSN： 1567-1739

eISSN： 1878-1675
Electrical transport properties of perpendicular magnetized Mn-Ga epitaxial films Peer-reviewed

Feng Wu, E. P. Sajitha, Shigemi Mizukami, Daisuke Watanabe, Terunobu Miyazaki, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

APPLIED PHYSICS LETTERS　96　(4)　042505-1-042505-3　2010/01

DOI： 10.1063/1.3298363 　

ISSN： 0003-6951

eISSN： 1077-3118
Ultrafast Demagnetization for Ni80Fe20 and Half-metallic Co2MnSi Heusler Alloy Films Peer-reviewed

S. Mizukami, S. Tunegi, T. Kubota, M. Oogane, D. Watanabe, H. Naganuma, Y. Ando, T. Miyazaki

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　042017-1-042017-4　2010

DOI： 10.1088/1742-6596/200/4/042017 　

ISSN： 1742-6588
Structural, Magnetic, and Magnetotransport Properties of FePt/MgO/CoPt Perpendicularly Magnetized Tunnel Junctions Peer-reviewed

N. Inami, G. Kim, T. Hiratsuka, H. Naganuma, M. Oogane, Y. Ando

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　052008-1-052008-4　2010

DOI： 10.1088/1742-6596/200/5/052008 　

ISSN： 1742-6588
Magnetotransport properties of CoFeB/MgO/CoFe/MgO/CoFeB double barrier magnetic tunnel junctions with large negative magnetoresistance at room temperature Peer-reviewed

L. X. Jiang, H. Naganuma, M. Oogane, K. Fujiwara, T. Miyazaki, K. Sato, T. J. Konno, S. Mizukami, Y. Ando

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　052009-1-052009-4　2010

DOI： 10.1088/1742-6596/200/5/052009 　

ISSN： 1742-6588
Magnetoresistance of Perpendicularly Magnetized Tunnel Junction Using L1(0)-CoNiPt with Low Saturation Magnetization Peer-reviewed

G. Kim, T. Hiratsuka, H. Naganuma, M. Oogane, Y. Ando

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　052011-1-052011-4　2010

DOI： 10.1088/1742-6596/200/5/052011 　

ISSN： 1742-6588
Structural and magnetic properties of Mn(2.5)Ga films Peer-reviewed

F. Wu, S. Mizukami, D. Watanabe, H. Naganuma, M. Oogane, Y. Ando, T. Miyazaki

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　062037-1-062037-4　2010

DOI： 10.1088/1742-6596/200/6/062037 　

ISSN： 1742-6588
Interlayer exchange coupling in perpendicularly magnetized synthetic ferrimagnet structure using CoCrPt and CoFeB Peer-reviewed

D. Watanabe, S. Mizukami, F. Wu, M. Oogane, H. Naganuma, Y. Ando, T. Miyazaki

INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)　200　072104-1-072104-4　2010

DOI： 10.1088/1742-6596/200/7/072104 　

ISSN： 1742-6588
Structure, exchange stiffness, and magnetic anisotropy of Co2MnAlxSi1-x Heusler compounds Peer-reviewed

Takahide Kubota, Jaroslav Hamrle, Yuya Sakuraba, Oksana Gaier, Mikihiko Oogane, Akimasa Sakuma, Burkard Hillebrands, Koki Takanashi, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　106　(11)　113907-1-113907-4　2009/12

DOI： 10.1063/1.3265428 　

ISSN： 0021-8979

eISSN： 1089-7550
Ferrimagnetism in epitaxially grown Mn₂VAl Heusler alloy investigatedby means of soft x-ray magnetic circular dichroism Peer-reviewed

T.Kubota, K. Kodama, T. Nakamura, Y. Sakuraba, M. Oogane, K. Takanashi, Y. Ando

Appl. Phys. Lett.　95　(22)　222503-1-222503-3　2009/11/30

DOI： 10.1063/1.3269609 　

ISSN： 0003-6951
Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier Peer-reviewed

S. Tsunegi, Y. Sakuraba, M. Oogane, N. D. Telling, L. R. Shelford, E. Arenholz, G. van der Laan, R. J. Hicken, K. Takanashi, Y. Ando

JOURNAL OF PHYSICS D-APPLIED PHYSICS　42　(19)　195004-1-195004-6　2009/10

DOI： 10.1088/0022-3727/42/19/195004 　

ISSN： 0022-3727

eISSN： 1361-6463
Study of Structure, Magnetic and Electrical Properties of Co2MnSi Heusler Alloy Thin Films Onto n-Si Substrates Peer-reviewed

M. A. I. Nahid, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　45　(10)　4030-4032　2009/10

DOI： 10.1109/TMAG.2009.2024320 　

ISSN： 0018-9464

eISSN： 1941-0069
Silica coating of Co-Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone) Peer-reviewed

Yoshio Kobayashi, Hidekazu Kakinuma, Daisuke Nagao, Yasuo Ando, Terunobu Miyazaki, Mikio Konno

JOURNAL OF NANOPARTICLE RESEARCH　11　(7)　1787-1794　2009/10

DOI： 10.1007/s11051-009-9617-y 　

ISSN： 1388-0764
Direct Observation of Atomic Ordering and Interface Structure in Co2MnSi/MgO/Co2MnSi Magnetic Tunnel Junctions by High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy Peer-reviewed

Toyoo Miyajima, Mikihiko Oogane, Yasutoshi Kotaka, Takashi Yamazaki, Mineharu Tsukada, Yuji Kataoka, Hiroshi Naganuma, Yasuo Ando

APPLIED PHYSICS EXPRESS　2　(9)　093001-1-093001-3　2009/09

DOI： 10.1143/APEX.2.093001 　

ISSN： 1882-0778

eISSN： 1882-0786
Large Tunnel Magnetoresistance of 1056% at Room Temperature in MgO Based Double Barrier Magnetic Tunnel Junction (Retracted article. See vol. 4, artn no. 019201, 2011) Peer-reviewed

Lixian Jiang, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando

APPLIED PHYSICS EXPRESS　2　(8)　083002-1-083002-3　2009/08

DOI： 10.1143/APEX.2.083002 　

ISSN： 1882-0778

eISSN： 1882-0786
Enhancement in tunnel magnetoresistance effect by inserting CoFeB to the tunneling barrier interface in Co2MnSi/MgO/CoFe magnetic tunnel junctions Peer-reviewed

S. Tsunegi, Y. Sakuraba, M. Oogane, Hiroshi Naganuma, K. Takanashi, Y. Ando

APPLIED PHYSICS LETTERS　94　(25)　252503-1-252503-3　2009/06

DOI： 10.1063/1.3156858 　

ISSN： 0003-6951

eISSN： 1077-3118
Structural, magnetic, and ferroelectric properties of multiferroic BiFeO3-based composite films with exchange bias Peer-reviewed

Hiroshi Naganuma, Tomosato Okubo, Sho Sekiguchi, Yasuo Ando, Soichiro Okamura

JOURNAL OF APPLIED PHYSICS　105　(7)　07D903-1-07D903-3　2009/04

DOI： 10.1063/1.3055284 　

ISSN： 0021-8979
Tunnel magnetoresistance effect in magnetic tunnel junctions using epitaxial Co2FeSi Heusler alloy electrode Peer-reviewed

Mikihiko Oogane, Masatsugu Shinano, Yuya Sakuraba, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　105　(7)　07C903-1-07C903-3　2009/04

DOI： 10.1063/1.3062814 　

ISSN： 0021-8979

eISSN： 1089-7550
Fabrication of MgO-based magnetic tunnel junctions with CoCrPt perpendicularly magnetized electrodes Peer-reviewed

Daisuke Watanabe, Shigemi Mizukami, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　105　(7)　07C911-1-07C911-3　2009/04

DOI： 10.1063/1.3062816 　

ISSN： 0021-8979
Tunnel magnetoresistance effect in double magnetic tunnel junctions using half-metallic Heusler alloy electrodes Peer-reviewed

Yusuke Ohdaira, Mikihiko Oogane, Yasuo Ando

JOURNAL OF APPLIED PHYSICS　105　(7)　07C920-1-07C920-3　2009/04

DOI： 10.1063/1.3072023 　

ISSN： 0021-8979

eISSN： 1089-7550
Reduction in switching current using a low-saturation magnetization Co-Fe-(Cr, V)-B free layer in MgO-based magnetic tunnel junctions Peer-reviewed

Hitoshi Kubota, Akio Fukushima, Kay Yakushiji, Satoshi Yakata, Shinji Yuasa, Koji Ando, Mikihiko Ogane, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　105　(7)　07D117-1-07D117-3　2009/04

DOI： 10.1063/1.3068484 　

ISSN： 0021-8979

eISSN： 1089-7550
Low damping constant for Co2FeAl Heusler alloy films and its correlation with density of states Peer-reviewed

S. Mizukami, D. Watanabe, M. Oogane, Y. Ando, Y. Miura, M. Shirai, T. Miyazaki

JOURNAL OF APPLIED PHYSICS　105　(7)　07D306-1-07D306-3　2009/04

DOI： 10.1063/1.3067607 　

ISSN： 0021-8979
Electronic properties of Co2MnSi thin films studied by hard x-ray photoelectron spectroscopy Peer-reviewed

Siham Ouardi, Andrei Gloskovskii, Benjamin Balke, Catherine A. Jenkins, Joachim Barth, Gerhard H. Fecher, Claudia Felser, Mihaela Gorgoi, Marcel Mertin, Franz Schaefers, Eiji Ikenaga, Ke Yang, Keisuke Kobayashi, Takahide Kubota, Mikihiko Oogane, Yasuo Ando

JOURNAL OF PHYSICS D-APPLIED PHYSICS　42　(8)　084011-1-084011-8　2009/04

DOI： 10.1088/0022-3727/42/8/084011 　

ISSN： 0022-3727
Determination of exchange constants of Heusler compounds by Brillouin light scattering spectroscopy: application to Co2MnSi Peer-reviewed

J. Hamrle, O. Gaier, Seong-Gi Min, B. Hillebrands, Y. Sakuraba, Y. Ando

JOURNAL OF PHYSICS D-APPLIED PHYSICS　42　(8)　084005-1-084005-6　2009/04

DOI： 10.1088/0022-3727/42/8/084005 　

ISSN： 0022-3727
Improvement of structural, electronic, and magnetic properties of Co2MnSi thin films by He+ irradiation Peer-reviewed

O. Gaier, J. Hamrle, B. Hillebrands, M. Kallmayer, P. Poersch, G. Schoenhense, H. J. Elmers, J. Fassbender, A. Gloskovskii, C. A. Jenkins, C. Felser, E. Ikenaga, Y. Sakuraba, S. Tsunegi, M. Oogane, Y. Ando

APPLIED PHYSICS LETTERS　94　(15)　152508-1-152508-3　2009/04

DOI： 10.1063/1.3119188 　

ISSN： 0003-6951

eISSN： 1077-3118
Half-metallicity and Gilbert damping constant in Co2FexMn1-xSi Heusler alloys depending on the film composition Peer-reviewed

Takahide Kubota, Sumito Tsunegi, Mikihiko Oogane, Shigemi Mizukami, Terunobu Miyazaki, Hiroshi Naganuma, Yasuo Ando

APPLIED PHYSICS LETTERS　94　(12)　122504-1-122504-3　2009/03

DOI： 10.1063/1.3105982 　

ISSN： 0003-6951

eISSN： 1077-3118
Large voltage-induced magnetic anisotropy change in a few atomic layers of iron Peer-reviewed

T. Maruyama, Y. Shiota, T. Nozaki, K. Ohta, N. Toda, M. Mizuguchi, A. A. Tulapurkar, T. Shinjo, M. Shiraishi, S. Mizukami, Y. Ando, Y. Suzuki

NATURE NANOTECHNOLOGY　4　(3)　158-161　2009/03

DOI： 10.1038/NNANO.2008.406 　

ISSN： 1748-3387
Epitaxial Mn2.5Ga thin films with giant perpendicular magnetic anisotropy for spintronic devices Peer-reviewed

Feng Wu, Shigemi Mizukami, Daisuke Watanabe, Hiroshi Naganuma, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS LETTERS　94　(12)　122503-1-122503-3　2009/03

DOI： 10.1063/1.3108085 　

ISSN： 0003-6951
Structural and Magnetic Properties of Co2MnSi Heusler Alloy Thin Films on Si Peer-reviewed

M. Ariful Nahid, M. Oogane, H. Naganuma, Y. Ando

Jpn. J. Appl. Phys.　48　(8)　83002-083002-3　2009
Publisher: The Japan Society of Applied Physics
DOI： 10.1143/JJAP.48.083002 　

ISSN： 0021-4922

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The structural and magnetic properties of Co2MnSi thin films grown on n-doped Si(110) and Si(100) substrates were studied and observed to have a strong dependence on annealing temperature ($T_{\text{A } }$). At $T_{\text{A } }=275--350$ °C, the Co2MnSi films exhibited the B2 phase with a $\langle 100\rangle$ orientation and a magnetic moment on both substrates. The saturation magnetization ($M_{\text{S } }$) of Co2MnSi thin films was observed to reach a maximum at $T_{\text{A } }=300$ °C, above which it was found to decrease. We consider that at $T_{\text{A } }\simeq 300$ °C, the Co2MnSi thin films on Si substrates exhibited the $\langle 100\rangle$ orientation, a high $M_{\text{S } }$ and a low roughness which might promote spin injection.
The effect of MgO barrier on the structure and magnetic properties of Co2MnSi films on n-Si(100) substrates Peer-reviewed

M. A. I. Nahid, M. Oogane, H. Naganuma, Y. Ando

J. Appl. Phys.　2009

DOI： 10.1063/1.3260253 　
Boron Composition Dependence of Spin-Transfer Switching in Magnetic Tunnel Junctions with CoFeB Free Layers Peer-reviewed

Daisuke Watanabe, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando, Terunobu Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS　48　(1)　013001-1-013001-4　2009/01

DOI： 10.1143/JJAP.48.013001 　

ISSN： 0021-4922

eISSN： 1347-4065
Room Temperature Ferroelectric and Magnetic Properties of Multiferroic Cobalt Substituted Bi Ferrite Films Peer-reviewed

H. Naganuma, J. Miura, K. Kamishima, K. Makizaki, N. Hiratsuka, Y. Ando, S. Okamura

J. Magn. Soc. Jpn.　33　(3)　237-241　2009
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RC8081 　

ISSN： 1882-2924

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Co substituted BiFeO₃ polycrystalline films were fabricated on Pt/Ti/SiO₂/Si(100) substrates by a chemical solution deposition method that was followed by post-deposition annealing between 673 and 1073 K. The substitution of cobalt at B-sites for iron in BiFeO₃ was promoted at relatively high temperatures, and saturated at around 923 K. The leakage current density was suppressed by substituting Co; therefore, ferroelectricity could be observed at room temperature. The remanent polarization increased by substituting Co due to the reduced electric coercive field. The saturation magnetization increased by promoting Co substitution, and a magnetic coercive field of 1.5 kOe and remanent magnetization of 3 emu/cm³ were obtained by annealing at 923 K. This indicated that Co substituted BiFeO₃ films are candidate materials that enable ferromagnetism and ferroelectricity to coexist above room temperature.
Fabrication and Characterization of Micro-fabricated Double Magnetic Tunnel Junctions Using Co2MnSi Electrodes Peer-reviewed

Y. Ohdara, M. Oogane, Y, Ando

Magn. Soc. Jpn.　33　(3)　262-265　2009
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RE8052 　

ISSN： 1882-2924

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Double magnetic tunnel junctions (DMTJs) using half-metallic Heusler alloy Co₂MnSi electrodes were fabricated. A tunnel magneto-resistance ratio as large as 25% (at RT) and 320% (at 6 K) was observed in the DMTJs with various junction areas. The dependence of the tunnel magneto-resistance on bias voltage was a typical characteristic of DMTJs. These results indicate that high-quality DMTJs were stably fabricated.
Fabrication of Synthetic Ferrimagnetic Structures with Both High Annealing Stability and Strong Interlayer Exchange Coupling, Peer-reviewed

M. Nishimura, D. Watanabe, M. Oogane, Y, Ando

J. Magn. Soc. Jpn.　33　(3)　266-269　2009
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RE8054 　

ISSN： 1882-2924

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We investigated the dependencies of the saturation field, H_s, for synthetic ferrimagnetic (SyF) structures with various stacking structures on annealing temperature and Ru middle layer thickness. The buffer layer was optimized using Co₇₅Fe₂₅/Ru/Co₇₅Fe₂₅-SyF. The SyF on the Ta/Ru buffer layer demonstrated high annealing stability and large H_s. Moreover, we investigated the dependence on annealing temperature of H_s for Ta(5 nm)/Ru(5 nm)/ ferromagnetic-layer/Ru(0.8 nm)/Co₄₀Fe₄₀B₂₀(2 nm) SyFs with various ferromagnetic layers. The SyFs using Co₇₅ Fe₂₅ and Ni₈₀Fe₂₀ ferromagnetic layers exhibited high annealing stability and large H_s. The dependence on Ru middle layer thickness of H_s for the SyFs consisting of Ta(5 nm)/Ru(5 nm)/Co₇₅ Fe₂₅(2 nm)/Ru(0.2-1.2 nm)/Co₄₀Fe₄₀B₂₀(2 nm)/ MgO(2.5 nm)/Ta(10 nm) was investigated. As a result, we demonstrated the possibility of fabricating CoFeB/MgO/ CoFeB MTJs with SyF having both high annealing stability and strong interlayer exchange coupling.
Magnetic Damping Constant of Co2FeMnSi Heusler Alloy Thin Films Peer-reviewed

M. Oogane, T. Kubota, N. Hirose, Y, Ando

J. Magn. Soc. Jpn　33　(3)　270-273　2009
Publisher: The Magnetics Society of Japan
DOI： 10.3379/msjmag.0903RE8063 　

ISSN： 1882-2924

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Magnetic damping constants of Co₂Fe_xMn_1-xSi (x = 0.0 - 1.0) Heusler alloy thin films have been investigated. Co₂Fe_xMn_1-xSi thin films were epitaxitially grown on the single crystal MgO(100) substrate using magnetron sputtering technique. Damping constants were estimated by analyzing the line width of ferromagnetic resonance (FMR) spectra. Damping constant of Co₂Fe_xMn_1-xSi films showed a minimum value of 0.003 at x = 0.4. This damping constant is very small compared with other ferromagnetic metals. Additionally, damping constants significantly increased above x = 0.6. In this article, the relationship between the damping constant and the half-metallicity of Co₂Fe_xMn_1-xSi films is discussed.
Gilbert Damping for Various Ni80Fe20 Thin Films Investigated Using All-Optical Pump-Probe Detection and Ferromagnetic Resonance Peer-reviewed

Shigemi Mizukami, Hiroyuki Abe, Daisuke Watanabe, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS EXPRESS　1　(12)　121301-1-121301-3　2008/12

DOI： 10.1143/APEX.1.121301 　

ISSN： 1882-0778
Evidence of local moment formation in Co-based Heusler alloys Peer-reviewed

N. D. Telling, P. S. Keatley, G. van der Laan, R. J. Hicken, E. Arenholz, Y. Sakuraba, M. Oogane, Y. Ando, K. Takanashi, A. Sakuma, T. Miyazaki

PHYSICAL REVIEW B　78　(18)　184438-1-184438-7　2008/11

DOI： 10.1103/PhysRevB.78.184438 　

ISSN： 2469-9950

eISSN： 2469-9969
Electrical conductance properties for magnetic tunnel junctions with MgO barriers Peer-reviewed

K. Tamanoi, M. Sato, M. Oogane, Y. Ando, T. Tanaka, Y. Uehara, T. Uzumaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　320　(22)　2959-2962　2008/11

DOI： 10.1016/j.jmmm.2008.08.004 　

ISSN： 0304-8853
Penetration Depth of Transverse Spin Current in Ferromagnetic Metals Peer-reviewed

Tomohiro Taniguchi, Satoshi Yakata, Hiroshi Imamura, Yasuo Ando

IEEE TRANSACTIONS ON MAGNETICS　44　(11)　2636-2639　2008/11

DOI： 10.1109/TMAG.2008.2003036 　

ISSN： 0018-9464
Large tunnel magnetoresistance in magnetic tunnel junctions using a Co2MnSi Heusler alloy electrode and a MgO barrier Peer-reviewed

Sumito Tsunegi, Yuya Sakuraba, Mikihiko Oogane, Koki Takanashi, Yasuo Ando

APPLIED PHYSICS LETTERS　93　(11)　112506-1-112506-3　2008/09

DOI： 10.1063/1.2987516 　

ISSN： 0003-6951
Annealing temperature dependences of ferroelectric and magnetic properties in polycrystalline Co-substituted BiFeO3 films Peer-reviewed

Hiroshi Naganuma, Jun Miura, Mitsumasa Nakajima, Hiromi Shima, Soichiro Okamura, Shintaro Yasui, Hiroshi Funakubo, Ken Nishida, Takashi Iijima, Masaki Azuma, Yasuo Ando, Kenji Kamishima, Koichi Kakizaki, Nobuyuki Hiratsuka

JAPANESE JOURNAL OF APPLIED PHYSICS　47　(9)　7574-7578　2008/09

DOI： 10.1143/JJAP.47.7574 　

ISSN： 0021-4922

eISSN： 1347-4065
Temperature dependence of the interface moments in Co2MnSi thin films Peer-reviewed

N. D. Telling, P. S. Keatley, L. R. Shelford, E. Arenholz, G. van der Laan, R. J. Hicken, Y. Sakuraba, S. Tsunegi, M. Oogane, Y. Ando, K. Takanashi, T. Miyazaki

APPLIED PHYSICS LETTERS　92　(19)　192503-1-192503-3　2008/05

DOI： 10.1063/1.2927482 　

ISSN： 0003-6951

eISSN： 1077-3118
Spin transfer switching in the nanosecond regime for CoFeB/MgO/CoFeB ferromagnetic tunnel junctions Peer-reviewed

Tatsuya Aoki, Yasuo Ando, Daisuke Watanabe, Mikihiko Oogane, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　103　(10)　103911-1-103911-4　2008/05

DOI： 10.1063/1.2930873 　

ISSN： 0021-8979
Influence of the L2(1) ordering degree on the magnetic properties of Co2MnSi Heusler films Peer-reviewed

O. Gaier, J. Hamrle, S. J. Hermsdoerfer, H. Schultheiss, B. Hillebrands, Y. Sakuraba, M. Oogane, Y. Ando

JOURNAL OF APPLIED PHYSICS　103　(10)　103910-1-103910-3　2008/05

DOI： 10.1063/1.2931023 　

ISSN： 0021-8979

eISSN： 1089-7550
Tunneling magnetoresistance of magnetic tunnel junctions using perpendicular magnetization L1(0)-CoPt electrodes Peer-reviewed

Gukcheon Kim, Yuya Sakuraba, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS LETTERS　92　(17)　172502-1-172502-3　2008/04

DOI： 10.1063/1.2913163 　

ISSN： 0003-6951
Magnetic second harmonic generation at the Co2MnSi/AlOx interface Peer-reviewed

L. R. Shelford, Y. Liu, R. J. Hicken, Y. Sakuraba, M. Oogane, Y. Ando

JOURNAL OF APPLIED PHYSICS　103　(7)　07D720-1-07D720-3　2008/04

DOI： 10.1063/1.2841174 　

ISSN： 0021-8979

eISSN： 1089-7550
Determination of penetration depth of transverse spin current in ferromagnetic metals by spin pumping Peer-reviewed

Tomohiro Taniguchi, Satoshi Yakata, Hiroshi Imamura, Yasuo Ando

APPLIED PHYSICS EXPRESS　1　(3)　031301-1-031301-3　2008/03

DOI： 10.1143/APEX.1.031302 　

ISSN： 1882-0778
Tunnel magnetoresistance effect in magnetic tunnel junctions using a Co2MnSi(110) electrode Peer-reviewed

Masashi Hattori, Yuya Sakuraba, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

APPLIED PHYSICS EXPRESS　1　(2)　021301-1-021301-3　2008/02

DOI： 10.1143/APEX.1.021301 　

ISSN： 1882-0778

eISSN： 1882-0786
Nonquasiparticle states in Co2MnSi evidenced through magnetic tunnel junction spectroscopy measurements Peer-reviewed

L. Chioncel, Y. Sakuraba, E. Arrigoni, M. I. Katsnelson, M. Oogane, Y. Ando, T. Miyazaki, E. Burzo, A. I. Lichtenstein

PHYSICAL REVIEW LETTERS　100　(8)　086402-1-086402-4　2008/02

DOI： 10.1103/PhysRevLett.100.086402 　

ISSN： 0031-9007

eISSN： 1079-7114
スピントロニクスの形成と発展 Invited Peer-reviewed

宮﨑照宣, 大兼幹彦, 桜庭裕弥, 渡邉大輔, R. Yilgin, 佐久間昭正, 安藤康夫, 久保田均

粉体および粉末治金　55　(2)　109-115　2008
Publisher: Japan Society of Powder and Powder Metallurgy
DOI： 10.2497/jjspm.55.109 　

ISSN： 0532-8799

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History about the research of magnetoresistance effect was reviewed. Also, we looked back on the research trends in the past when both giant magnetoresistance of Fe/Cr multi layered films and large tunnel magnetoresistance at room temperature were found. Special emphasis was placed on the recent developments of huge TMR ratio for both MgO barrier tunnel junctions and Heusler alloy electrode tunnel junctions which contribute further to the development of spinelectronic research fields. Principle and importance of spin-transfer torque were also explained.
Spin-Transfer Switching Property in the Nanosecond Regime for CoFeB/MgO/CoFeB Tunnel Junctions and the Real-Time Observation Peer-reviewed

T. Aoki, M. Oogane, T. Miyazaki, Y. Ando

J. Magn. Soc. Jpn.　32　(3)　355-360　2008
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.355 　

ISSN： 1882-2924

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Detailed spin-transfer switching (STS) properties in the nanosecond regime were investigated. We prepared a CoFeB/MgO/CoFeB magnetic tunnel junction that exhibits a 115 % magnetoresistance ratio. The STS property in the ≥ 2 ns region was obtained by static measurement. We then examined this property from several points of view. In addition, we outlined a new method of real-time switching observation. That is expected to clarify the STS mechanism directly. Using this method, the contribution of the thermal activation effect in a switching current below I_C0 was successfully detected. This indicates that the real-time method has the advantage that it clarifies the STS mechanism.
Development of Highly Sensitive Terrestrial Sensor using TMR Junctions Peer-reviewed

F. Kou, M. Oogane, Y. Ando

J. Magn. Soc. Jpn.　32　(3)　361-365　2008
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.361 　

ISSN： 1882-2924

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The TMR (Tunneling Magneto-resistive) junctions of SiO₂-sub./bottom-electrode/IrMn/CoFe/Al-oxide/NiFe/ top-electrode were fabricated. We have succeeded to observe both high sensitivity and linearity in a low magnetic field for the optimized TMR junctions. The circuit of magnetic sensor using developed TMR junctions exhibited high output signal enough to resolve over 36 directions at terrestrial magnetism. The terrestrial sensor using TMR junctions is very small size and low energy consumption, so will be key "tools" for some solutions, for example, a navigation sensor with Global Positioning System(GPS) in cell phones.
X-ray Diffraction and Magnetic Study of Highly-Oriented Nd₂Fe₁₄B Thin Films Peer-reviewed

Ogawa, T. Akiya, M. Oogane, Y. Ando, H. Kato

J. Magn. Soc. Jpn.　32　(6)　548-553　2008
Publisher: The Magnetics Society of Japan (MSJ)
DOI： 10.3379/msjmag.32.548 　

ISSN： 1882-2924

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Nd₂Fe₁₄B thin films were fabricated with a DC magnetron sputtering system. X-ray diffraction experiments and the Rietveld analysis showd that the crystallites of the Nd₂Fe₁₄B phase were highly oriented perpendicular to the film plane. In addition to the diffraction peaks originated from the Nd₂Fe₁₄B phase, we observed extra reflections that can be assigned as a NdO phase. The relative intensity, hence the volume fraction of the NdO phase varied depending on the sputtering conditions such as the substrate temperature, Ar gas pressure, and Ta buffer layer thickness. It was found that the magnetization value depends strongly on the Ar gas pressure and reaches a maximum at 0.7 Pa of Ar gas pressure. The maximum magnetization value is 15 kG, which is comparable with the bulk value. The optimized values of the maximum energy product, saturation magnetization, and coercivity are (BH)_max = 36 MGOe, 4πM_s = 14.7 kG, and H_c = 6.7 kOe, respectively.
Development of high-sensitive magnetoresistance devices using half-metallic Heusler alloy Co₂MnSi, Peer-reviewed

Yuya SAKURABA, Taku IWASE, Sumito TSUNEGI, Kesami SAITO, Mikihiko OGANE, Yasuo ANDO, Akimasa SAKUMA, Koki TAKANASHI

IEICE Technical Report,　103　13-18　2008
Ultrafast optical modification of magnetic anisotropy and stimulated precession in an epitaxial Co2MnAl thin film Peer-reviewed

Y. Liu, L. R. Shelford, V. V. Kruglyak, R. J. Hicken, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF APPLIED PHYSICS　101　(9)　09C106-1-09C106-3　2007/05

DOI： 10.1063/1.2711702 　

ISSN： 0021-8979

eISSN： 1089-7550
Magnetic damping constant of Co2FeSi Heusler alloy thin film Peer-reviewed

Mikihiko Oogane, Resul Yilgin, Masatsugu Shinano, Satoshi Yakata, Yuya Sakuraba, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF APPLIED PHYSICS　101　(9)　09J501-1-09J501-3　2007/05

DOI： 10.1063/1.2709751 　

ISSN： 0021-8979

eISSN： 1089-7550
Tunneling spin polarization and magnetic properties of Co-Fe-B alloys and their dependence on boron content Peer-reviewed

Takahide Kubota, Tadaomi Daibou, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　46　(8-11)　L250-L252　2007/03

DOI： 10.1143/JJAP.46.L250 　

ISSN： 0021-4922
Thermally excited spin wave modes in synthetic antiferromagnetic stripes Peer-reviewed

Yasuo Ando, Young Min Lee, Tatsuya Aoki, Terunobu Miyazaki, Helmut Schultheiss, Burkard Hillebrands

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　1949-1951　2007/03

DOI： 10.1016/j.jmmm.2006.10.828 　

ISSN： 0304-8853
Enhancement of DC voltage generated in ferromagnetic resonance for magnetic thin film Peer-reviewed

S. Mizukami, S. Nagashima, S. Yakata, Y. Ando, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　2248-2249　2007/03

DOI： 10.1016/j.jmmm.2006.10.827 　

ISSN： 0304-8853
Gilbert damping constant in polycrystalline CO2MnSi Heusler alloy films Peer-reviewed

R. Yilgin, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　2322-2323　2007/03

DOI： 10.1016/j.jmmm.2006.11.032 　

ISSN： 0304-8853
Bias voltage dependence of tunnel magnetoresistance effect in CoFeB/MgO/Co2X(X = Fe, Mn)Si magnetic tunnel junctions Peer-reviewed

T. Daibou, M. Shinano, M. Hattori, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　1926-1928　2007/03

DOI： 10.1016/j.jmmm.2006.10.761 　

ISSN： 0304-8853
Spin injection into organic light-emitting diodes with a ferromagnetic cathode and observation of the luminescence properties Peer-reviewed

Eiji Shikoh, Toru Kawai, Akihiko Fujiwara, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　2052-2054　2007/03

DOI： 10.1016/j.jmmm.2006.10.981 　

ISSN： 0304-8853
Boron effects on noise in magnetic tunnel junctions Peer-reviewed

A. F. Md Nor, T. Daibou, M. Oogane, Y. Ando, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　1917-1919　2007/03

DOI： 10.1016/j.jmmm.2006.10.1126 　

ISSN： 0304-8853
Anisotropic intrinsic damping constant of epitaxial Co2MnSi Heusler alloy films Peer-reviewed

Resul Yilgin, Yuya Sakuraba, Mikihiko Oogane, Shigemi Mizukami, Yasuo Ando, Terunobu Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　46　(8-11)　L205-L208　2007/03

DOI： 10.1143/JJAP.46.L205 　

ISSN： 0021-4922
Half-metallic band structure observed in Co2MnSi-based magnetic tunnel junctions Peer-reviewed

Y. Sakuraba, M. Hattori, M. Oogane, H. Kubota, Y. Ando, A. Sakuma, T. Miyazaki

JOURNAL OF PHYSICS D-APPLIED PHYSICS　40　(5)　1221-1227　2007/03

DOI： 10.1088/0022-3727/40/5/S02 　

ISSN： 0022-3727
Reduction of switching fields of submicrometer sized magnetic tunnel junction with NiFe-based synthetic ferrimagnetic free layer Peer-reviewed

Young Min Lee, Yasuo Ando, Terunobu Miyazaki, Hitoshi Kubota

JOURNAL OF APPLIED PHYSICS　101　(2)　023905-1-023905-3　2007/01

DOI： 10.1063/1.2424399 　

ISSN： 0021-8979
Fabrication of Magnetic Tunnel Junction with Co₂MnSi(110) Epitaxial Film Peer-reviewed

M. Hattori, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　31　(2)　89-93　2007
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.89 　

ISSN： 0285-0192

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According to Julliere's model, magnetic tunnel junctions (MTJs) with half-metallic electrodes lead to a large tunnel magnetoresistance (TMR) ratio. A Co₂MnSi Heusler alloy is theoretically expected to exhibit half-metallicity. We fabricated (110)-oriented epitaxial Co₂MnSi electrodes on sapphire substrates using W and Ta/W/Cr buffer layers. With the W buffer layer, we found that the W and Co₂MnSi layers formed a twin structure. However, with the Ta/W/Cr multi-buffer layers, we succeeded in fabricating a high-quality Co₂MnSi(110) epitaxial electrode. We fabricated a MTJ with the high-quality Co₂MnSi(110) electrode and investigated TMR effects in the MTJ. As a result, we observed a TMR ratio of about 40% at room temperature and 120% at 2 K.
Fabrication of small ferromagnetic tunnel junction with coplanar wave guide Peer-reviewed

T. Aoki, D. Watanabe, T. Daibou, Y. Ando, M. Oogane, T. Miyazaki

J. Magn. Soc. Jpn.　31　(2)　94-97　2007
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.94 　

ISSN： 0285-0192

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Investigation of current induced magnetization switching properties in nanosecond regime in ferromagnetic tunnel junctions is increasing its necessity for realization of fast operating magnetic random access memory (MRAM). In this work, appropriate electrode structures for such a measurement were investigated. The electrode structure was designed as a typical coplanar waveguide with 50Ω characteristic impedance (structure A). Although the buffer layer thickness and the distance between the signal line and the ground line were altered, the large frequency dependenceof the insertion loss was not improved. The revised structure (structure B) with small cross section area between the signal line and the ground line showed very flat transmission properties over 20 GHz. Consequently, submicron sized Ta/FeNi/IrMn/CoFe/Ru/CoFeB/MgO/CoFeB/Ta/Ru ferromagnetic tunnel junctions with the electrodes of structure Bwere fabricated. The tunnel magnetoresistance ratio was 108 % after annealing at 250 °C.
Measurement of Magnetic Damping Parameters in Co-Fe-B Thin Films Peer-reviewed

M. Oogane, M. Watanabe, S. Yakata, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　31　(3)　209-212　2007
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.31.209 　

ISSN： 0285-0192

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We investigated magnetic damping parameters (α) in Co-Fe-B alloy thin films having various compositions, thicknesses, and annealing temperatures. Ferromagnetic resonance (FMR) was used to determine α values. The out-of-plane angular dependencies of the resonance field and the line width of FMR spectra were measured and analyzed by using the Landau-Lifshitz-Gilbert equation, taking the effect of magnetic inhomogeneities in the films into consideration. The Co-Fe-B films with an fcc structure phase had a larger α value than that of the film with a bcc structure. The damping parameter of the Co-Fe-B film was increased by increasing the B concentration and annealing temperature, and the very thin Co-Fe-B film (∼2 nm) had a large damping parameter. We discuss the advantages of Co-Fe-B thin film as a material for current-induced magnetization switching (CIMS) systems.
Perfect spin-polarized state observed in magnetic tunnel junctions with Co2MnSi electrode Peer-reviewed

Y. Sakuraba, M. Hattori, M. Oogane, H. Kubota, Y. Ando, A. Sakuma, N. D. Telling, P. Keatley, G. van, der Laan, E. Arenholz, R. J. Hicken, T. Miyazaki

J. Magn. Soc. Jpn.　31　338-343　2007

DOI： 10.3379/jmsjmag.31.338 　
Interfacial structure and half-metallic ferromagnetism in Co2MnSi-based magnetic tunnel junctions Peer-reviewed

N. D. Telling, P. S. Keatley, G. van der Laan, R. J. Hicken, E. Arenholz, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki

PHYSICAL REVIEW B　74　(22)　224439-1-224439-7　2006/12

DOI： 10.1103/PhysRevB.74.224439 　

ISSN： 2469-9950

eISSN： 2469-9969
Tunnel magnetoresistance effect in CoFeB/MgO/Co2FeSi and Co2MnSi tunnel junctions Peer-reviewed

T. Daibou, M. Shinano, M. Hattori, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki

IEEE TRANSACTIONS ON MAGNETICS　42　(10)　2655-2657　2006/10

DOI： 10.1109/TMAG.2006.879733 　

ISSN： 0018-9464

eISSN： 1941-0069
Spin injection into organic light-emitting devices with ferromagnetic cathode and effects on their luminescence properties Peer-reviewed

Eiji Shikoh, Akihiko Fujiwara, Yasuo Ando, Terunobu Miyazaki

Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers　45　(9 A)　6897-6901　2006/09/07

DOI： 10.1143/JJAP.45.6897 　

ISSN： 0021-4922 1347-4065
Direct observation of half-metallic energy gap in Co2MnSi by tunneling conductance spectroscopy Peer-reviewed

Y. Sakuraba, T. Miyakoshi, M. Oogane, Y. Ando, A. Sakuma, T. Miyazaki, H. Kubota

APPLIED PHYSICS LETTERS　89　(5)　052508-1-052508-3　2006/07

DOI： 10.1063/1.2335583 　

ISSN： 0003-6951

eISSN： 1077-3118
Preparation of silica-coated Co-Pt alloy nanoparticles Peer-reviewed

Yoshio Kobayashi, Mitsuru Horie, Daisuke Nagao, Yasuo Ando, Terunobu Miyazaki, Mikio Konno

MATERIALS LETTERS　60　(16)　2046-2049　2006/07

DOI： 10.1016/j.matlet.2005.12.078 　

ISSN： 0167-577X
Giant tunneling magnetoresistance in Co2MnSi/Al-O/Co2MnSi magnetic tunnel junctions Peer-reviewed

Y. Sakuraba, M. Hattori, M. Oogane, Y. Ando, H. Kato, A. Sakuma, T. Miyazaki, H. Kubota

APPLIED PHYSICS LETTERS　88　(19)　192508-1-192508-3　2006/05

DOI： 10.1063/1.2202724 　

ISSN： 0003-6951

eISSN： 1077-3118
Magnetic damping in ferromagnetic thin films Peer-reviewed

Mikihiko Oogane, Takeshi Wakitani, Satoshi Yakata, Resul Yilgin, Yasuo Ando, Akimasa Sakuma, Terunobu Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS　45　(5A)　3889-3891　2006/05

DOI： 10.1143/JJAP.45.3889 　

ISSN： 0021-4922
Temperature dependences of spin-diffusion lengths of Cu and Ru layers Peer-reviewed

S Yakata, Y Ando, T Miyazaki, S Mizukami

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS　45　(5A)　3892-3895　2006/05

DOI： 10.1143/JJAP.45.3892 　

ISSN： 0021-4922
Tunneling spectroscopy in CoFeB/MgO/CoFeB magnetic tunnel junctions Peer-reviewed

K Ono, T Daibou, SJ Ahn, Y Sakuraba, T Miyakoshi, T Morita, Y Kikuchi, M Oogane, Y Ando, T Miyazaki

JOURNAL OF APPLIED PHYSICS　99　(8)　08A905-1-08A905-3　2006/04

DOI： 10.1063/1.2173628 　

ISSN： 0021-8979
Low-frequency noise in MgO magnetic tunnel junctions Peer-reviewed

AFM Nor, T Kato, SJ Ahn, T Daibou, K Ono, M Oogane, Y Ando, T Miyazaki

JOURNAL OF APPLIED PHYSICS　99　(8)　08T306-1-08T306-3　2006/04

DOI： 10.1063/1.2165142 　

ISSN： 0021-8979
Large tunnel magnetoresistance in magnetic tunnel junctions using Co2MnX (X = Al,Si) Heusler alloys Peer-reviewed

M Oogane, Y Sakuraba, J Nakata, H Kubota, Y Ando, A Sakuma, T Miyazaki

JOURNAL OF PHYSICS D-APPLIED PHYSICS　39　(5)　834-841　2006/03

DOI： 10.1088/0022-3727/39/5/S09 　

ISSN： 0022-3727
Low frequency noise in CoFeB magnetic tunnel junctions with varying boron content Peer-reviewed

A. F, Md. Nor, T. Daibou, M. Oogane, Y. Ando, T. Miyazaki

J. Magn. Magn. Mater.　2006

DOI： 10.1109/INTMAG.2006.374889 　
Gilbert Damping Constants of Co2FeSi Heusler Alloy Film Peer-reviewed

M. Oogane, R. Yilgin, S. Shinano, S. Yakata, H. Kubota, Y. Ando, T. Miyazaki

J. Appl. Phys.　2006
Co2MnSi (110)ホイスラー合金を用いたトンネル接合における磁気抵抗効果 Peer-reviewed

服部正志, 桜庭裕弥, 大兼幹彦, 安藤康夫, 宮﨑照宣

日本応用磁気学会誌　2006
Magnetic tunnel junctions using B2-ordered Co2MnAl Heusler alloy epitaxial electrode Peer-reviewed

Y Sakuraba, J Nakata, M Oogane, Y Ando, H Kato, A Sakuma, T Miyazaki, H Kubota

APPLIED PHYSICS LETTERS　88　(2)　022503-1-022503-3　2006/01

DOI： 10.1063/1.2162867 　

ISSN： 0003-6951
FMRを用いた強磁性金属中におけるスピン拡散長の測定 Peer-reviewed

家形諭, 安藤康夫, 大兼幹彦, 宮崎照宣

日本応用磁気学会誌　31　2006
Intrinsic Gilbert damping constant in CO2MnAl Heusler alloy films Peer-reviewed

R Yilgin, M Oogane, S Yakata, Y Ando, T Miyazaki

IEEE TRANSACTIONS ON MAGNETICS　41　(10)　2799-2801　2005/10

DOI： 10.1109/TMAG.2005.854832 　

ISSN： 0018-9464

eISSN： 1941-0069
Spin-dependent tunneling spectroscopy in single-crystal Fe/MgO/Fe tunnel junctions Peer-reviewed

Y Ando, T Miyakoshi, M Oogane, T Miyazaki, H Kubota, K Ando, S Yuasa

APPLIED PHYSICS LETTERS　87　(14)　142502-1-142502-3　2005/10

DOI： 10.1063/1.2077861 　

ISSN： 0003-6951
Fabrication of Co2MnAl Heusler alloy epitaxial film using Cr buffer layer Peer-reviewed

Y Sakuraba, J Nakata, M Oogane, H Kubota, Y Ando, A Sakuma, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS　44　(9A)　6535-6537　2005/09

DOI： 10.1143/JJAP.44.6535 　

ISSN： 0021-4922
Influence of diffusion of Fe atoms into the emissive layer of an organic light-emitting device on the luminescence properties Peer-reviewed

Eiji Shikoh, Yasuo Ando, Terunobu Miyazaki

Journal of Applied Physics　97　(10)　10D501-1-10D501-2　2005/05/15

DOI： 10.1063/1.1845931 　

ISSN： 0021-8979
Fabrication and characterization of Co-Mn-Al Heusler-type thin film Peer-reviewed

H Kubota, J Nakata, M Oogane, Y Ando, H Kato, A Sakuma, T Miyazaki

JOURNAL OF APPLIED PHYSICS　97　(10)　10C913-1-10C913-3　2005/05

DOI： 10.1063/1.1852329 　

ISSN： 0021-8979

eISSN： 1089-7550
Fabrication of ferromagnetic single-electron tunneling devices by utilizing metallic nanowire as hard mask stencil Peer-reviewed

T Niizeki, H Kubota, Y Ando, T Miyazaki

JOURNAL OF APPLIED PHYSICS　97　(10)　10C909-1-10C909-3　2005/05

DOI： 10.1063/1.1850408 　

ISSN： 0021-8979
FMR spectrum-linewidth and spin diffusion length in Cu/NiFe₈₀Fe₂₀/N(N=Cu, Cu/Pt) Peer-reviewed

S. Yakata, Y. Ando, S. Mizukami, T. Miyazaki

J. Magn. Soc. Jpn.　29　(4)　450-454　2005/03
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.29.450 　

ISSN： 0285-0192

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We have investigated the magnetic damping in two types of multilayer films, Cu(10 nm)/Ni₈₀Fe₂₀(3 nm)/Cu (d_Cu) and Cu(10 nm)/Ni₈₀Fe₂₀(3 nm)/Cu(d_Cu)/Pt(2 nm). Temperature dependence of the damping parameter and FMR linewidth with various Cu thickness d_Cu were measured. Spin diffusion length increased with decreasing temperature. We also measured the temperature dependence of FMR linewidth for the Cu/Ni₈₀Fe₂₀/Cu(d_Cu)/Pt films with d_Cu=400 nm, 800 nm. The increase of FMR linewidth with decreasing temperature suggested that the damping increased by spin diffusion in Cu layer.
Bias-voltage dependence of magnetoresistance in magnetic tunnel junctions grown on Al2O3 (0001) substrates Peer-reviewed

SJ Ahn, T Kato, H Kubota, Y Ando, T Miyazaki

APPLIED PHYSICS LETTERS　86　(10)　102506-1-102506-3　2005/03

DOI： 10.1063/1.1870104 　

ISSN： 0003-6951

eISSN： 1077-3118
Fabrication of heusler-type Co2MnAl epitaxial films by using sputtering method

Y. Sakuraba, J. Nakata, M. Oogane, H. Kubota, Y. Ando, H. Kato, A. Sakuma, T. Miyazaki

INTERMAG ASIA 2005: Digests of the IEEE International Magnetics Conference　725　2005
Investigation of intrinsic gilbert damping constant in Co 2MnAl heusler alloy films

R. Yilgin, M. Oogane, S. Yakata, Y. Ando, T. Miyazaki

INTERMAG ASIA 2005: Digests of the IEEE International Magnetics Conference　936　2005
Bias-voltage dependence of tunnel magnetoresistance depending on the crystal structure of bottom ferromagentic electrode

Sung-Jin Ahn, Takeharu Kato, Hitoshi Kubota, Yasuo Ando, Terunobu Miyazaki

INTERMAG ASIA 2005: Digests of the IEEE International Magnetics Conference　997　2005
Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions Peer-reviewed

M Oogane, J Nakata, H Kubota, Y Ando, A Sakuma, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　44　(24-27)　L760-L762　2005

DOI： 10.1143/JJAP.44.L760 　

ISSN： 0021-4922
Huge spin-polarization of L2(1)-ordered Co2MnSi epitaxial Heusler alloy film Peer-reviewed

Y Sakuraba, J Nakata, M Oogane, H Kubota, Y Ando, A Sakuma, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　44　(33-36)　L1100-L1102　2005

DOI： 10.1143/JJAP.44.L1100 　

ISSN： 0021-4922
Switching properties and dynamic domain structures in double barrier magnetic tunnel junctions Peer-reviewed

XF Han, SF Zhao, FF Li, T Daibou, H Kubota, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　282　225-231　2004/11

DOI： 10.1016/j.jmmm.2004.04.051 　

ISSN： 0304-8853
A simple fabrication process using focused ion beam for deep submicron magnetic tunnel junctions Peer-reviewed

D Watanabe, H Kubota, Y Ando, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS　43　(11A)　7489-7490　2004/11

DOI： 10.1143/JJAP.43.7489 　

ISSN： 0021-4922
Spin-dependent inelastic electron tunneling spectroscopy of magnetic tunnel junctions Peer-reviewed

M Hayashi, Y Ando, M Oogane, H Kubota, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS　43　(11A)　7472-7476　2004/11

DOI： 10.1143/JJAP.43.7472 　

ISSN： 0021-4922
Large magnetoresistance in magnetic tunnel junctions using Co-Mn-Al full Heusler alloy Peer-reviewed

H Kubota, J Nakata, M Oogane, Y Ando, A Sakuma, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　43　(7B)　L984-L986　2004/07

DOI： 10.1143/JJAP.43.L984 　

ISSN： 0021-4922
Measurement of magnetization precession for NM/Ni80Fe20/NM (NM = Cu and Pt) using time-resolved Kerr effect Peer-reviewed

H Nakamura, Y Ando, S Mizukami, H Kubota, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　43　(6B)　L787-L789　2004/06

DOI： 10.1143/JJAP.43.L787 　

ISSN： 0021-4922
Tunnel spectra for Al/Al-oxide/Ni80Fe20 junctions under the superconducting transition temperature of Al films Peer-reviewed

M. Oogane, T. Daibou, H. Kubota, Y. Ando, T. Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1515-E1516　2004/05

DOI： 10.1016/j.jmmm.2003.12.318 　

ISSN： 0304-8853
CO+NH3 plasma etching for magnetic thin films Peer-reviewed

Hitoshi Kubota, Kousei Ueda, Yasuo Ando, Terunobu Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1421-E1422　2004/05

DOI： 10.1016/j.jmmm.2003.12.724 　

ISSN： 0304-8853
Nanofabrication of magnetic tunnel junctions by using electron beam lithography Peer-reviewed

T Niizeki, H Kubota, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　1947-1948　2004/05

DOI： 10.1016/j.jmmm.2003.12.387 　

ISSN： 0304-8853
Ferromagnetic tunnel junctions with high thermal stability Peer-reviewed

Y. Ando, S. Iura, H. Kubota, T. Miyazaki, C. S. Yoon, J. H. Lee, D. H. Im, C. K. Kim

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1507-E1509　2004/05

DOI： 10.1016/j.jmmm.2003.12.314 　

ISSN： 0304-8853
Time resolved luminescence properties of Al-q3 for spin-injection into organic semiconductor Peer-reviewed

E Shikoh, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　1921-1923　2004/05

DOI： 10.1016/j.jmmm.2003.12.1187 　

ISSN： 0304-8853
Time-resolved magnetization precession and reversal dynamics investigated using tunneling current and Kerr effect Peer-reviewed

Y Ando, H Nakamura, S Mizukami, H Kubota, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　293-294　2004/05

DOI： 10.1016/j.jmmm.2003.12.1245 　

ISSN： 0304-8853
Ferromagnetic Tunnel Junctions Using Co₂MnAl Heusler Alloy Peer-reviewed

J. Nakata, M. Oogane, H. Kubota, Y. Ando, H. Kato, T. Miyazaki

J. Magn. Soc. Jpn.　28　(4)　573-576　2004
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.573 　

ISSN： 0285-0192

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We investigated the structural and magnetic properties of Co₂MnAl thin films with Cr buffer layers, and the tunnel magnetoresistance (TMR) effect of junctions using Co₂MnAl Heusler alloy. The saturation magnetization of Co₂MnAl film deposited at 350°C was 711 emu/cm³ which was almost the same as that reported for bulk. The maximum TMR ratio of the junctions was 12% at room temperature and 26% at 25K. TMR ratio increased to 17% at room temperature after annealing at 200°C for one hour.
Fabrication of Small Magnetic Tunnel Junctions Using a Focused Ion Beam Peer-reviewed

D. Watabnabe, H. Kubota, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　28　(4)　569-572　2004
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.28.569 　

ISSN： 0285-0192

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A process for fabricating small magnetic tunnel junctions (MTJs) by using focused ion beam (FIB)-assisted chemical vapor deposition was investigated. Deposited tungsten was used as an electrode, and deposited carbon was used as a mask. MTJs with a junction area of 3 × 3 μm² showed a TMR ratio of about 30 % at room temperature.
Tunnel Conductance in Ni₈₀Fe₂₀/Al-oxide/Al Junctions below the superconducting transition temperature of the Al films Peer-reviewed

M. Oogane, H. Kubota, Y. Ando, T. Miyazaki

Transactions of .Material Research Society　29　1527-1530　2004
Characterization of thermally annealed tunnel junctions with preoxidized CoFe pinned electrode Peer-reviewed

JH Lee, DH Im, CS Yoon, CK Kim, Y Ando, H Kubota, T Miyazaki

JOURNAL OF APPLIED PHYSICS　94　(12)　7778-7783　2003/12

DOI： 10.1063/1.1628827 　

ISSN： 0021-8979
Magnetic tunnel junctions with doubly-plasma oxidized AlOx insulation layer Peer-reviewed

YM Lee, O Song, CS Yoon, CK Kim, Y Ando, H Kubota, T Miyazaki

MICROELECTRONICS JOURNAL　34　(9)　805-808　2003/09

DOI： 10.1016/S0026-2692(03)00138-1 　

ISSN： 0026-2692
Size dependence of switching field of magnetic tunnel junctions down to 50 nm scale Peer-reviewed

H Kubota, Y Ando, T Miyazaki, G Reiss, H Bruckl, W Schepper, J Wecker, G Gieres

JOURNAL OF APPLIED PHYSICS　94　(3)　2028-2032　2003/08

DOI： 10.1063/1.1588357 　

ISSN： 0021-8979
Nanofabrication of magnetic tunnel junctions by using side-edge thin film deposition Peer-reviewed

T. Niizeki, H. Kubota, Y. Ando, T. Miyazaki

SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS　4　(4)　347-352　2003/07

DOI： 10.1016/j.stam.2003.08.004 　

ISSN： 1468-6996
Electron transport properties in magnetic tunnel junctions with epitaxial NiFe (111) ferromagnetic bottom electrodes Peer-reviewed

JH Yu, HM Lee, Y Ando, T Miyazaki

APPLIED PHYSICS LETTERS　82　(26)　4735-4737　2003/06

DOI： 10.1063/1.1587271 　

ISSN： 0003-6951
Interface characterization of magnetic tunnel junctions by using tunneling spectroscopy Peer-reviewed

Y Ando, M Hayashi, M Oogane, H Kubota, T Miyazaki

JOURNAL OF APPLIED PHYSICS　93　(10)　7023-7025　2003/05

DOI： 10.1063/1.1540172 　

ISSN： 0021-8979

eISSN： 1089-7550
Hard mask fabrication for magnetic random access memory elements using focused ion beam assisted selective chemical vapor deposition Peer-reviewed

H Kubota, M Hamada, Y Ando, T Miyazaki

JOURNAL OF APPLIED PHYSICS　93　(10)　8370-8372　2003/05

DOI： 10.1063/1.1540058 　

ISSN： 0021-8979
Magnetic tunnel junctions with high magnetoresistance and small bias voltage dependence using epitaxial NiFe(111) ferromagnetic bottom electrodes Peer-reviewed

JH Yu, HM Lee, M Hayashi, M Oogane, T Daibou, H Nakamura, H Kubota, Y Ando, T Miyazaki

JOURNAL OF APPLIED PHYSICS　93　(10)　8555-8557　2003/05

DOI： 10.1063/1.1544458 　

ISSN： 0021-8979
Thermal Stability of Tunnel Junctions with additional oxidation at the surface of the bottom electrode Peer-reviewed

S. Iura, H. Kubota, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　27　(4)　303-306　2003
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.27.303 　

ISSN： 0285-0192

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The annealing temperature dependence of the tunnel magnetoresistance (TMR) ratio for ferromagnetic tunnel junctions with additional oxidation at the surface of the bottom ferromagnetic layer was measured. A drastic increase of TMR ratio was achieved at high temperature around 375°C. Such a tendency was very similar to the dependence for radical oxidized junctions. The enhancement of the thermal stability would be due to the existence of oxigen on the surface of the bottom ferromagnetic layer.
Recent Development of MRAM Technology Peer-reviewed

T. Miyazaki, Y. Ando, H. Kubota

Journal of Magnetics　8　36-44　2003
Spin Pumping in Ferromagnetic-Metal/Normal-Metal Junctions Peer-reviewed

S. Mizukami, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　27　934-939　2003
Growth mechanism of thin insulating layer in ferromagnetic tunnel junctions prepared using various oxidation methods Peer-reviewed

Y Ando, M Hayashi, S Iura, K Yaoita, CC Yu, H Kubota, T Miyazaki

JOURNAL OF PHYSICS D-APPLIED PHYSICS　35　(19)　2415-2421　2002/10

DOI： 10.1088/0022-3727/35/19/314 　

ISSN： 0022-3727

eISSN： 1361-6463
Effect of spin diffusion on Gilbert damping for a very thin permalloy layer in Cu/permalloy/Cu/Pt films Peer-reviewed

S. Mizukami, Y. Ando, T. Miyazaki

Physical Review B - Condensed Matter and Materials Physics　66　(10)　1044131-1044139　2002/09/01

DOI： 10.1103/PhysRevB.66.104413 　

ISSN： 0163-1829
Effect of diffusion barrier in the thermally annealed exchange-biased IrMn-CoFe electrode in magnetic tunnel junctions Peer-reviewed

CS Yoo, HD Jeong, JH Lee, CS Yoon, CK Kim, JH Yuh, Y Ando, H Kubota, T Miyazaki

IEEE TRANSACTIONS ON MAGNETICS　38　(5)　2715-2717　2002/09

DOI： 10.1109/TMAG.2002.803168 　

ISSN： 0018-9464
Effect of spin diffusion on Gilbert damping for a very thin permalloy layer in Cu/permalloy/Cu/Pt films Peer-reviewed

S Mizukami, Y Ando, T Miyazaki

PHYSICAL REVIEW B　66　(10)　104413-1-104413-9　2002/09

DOI： 10.1103/PhysRevB.66.104413 　

ISSN： 2469-9950

eISSN： 2469-9969
Magnetic relaxation of normal-metal (NM)/80NiFe/NM films Peer-reviewed

S Mizukami, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　239　(1-3)　42-44　2002/02

DOI： 10.1016/S0304-8853(01)00525-X 　

ISSN： 0304-8853
Micro structural and magnetic characteristics of IrMn exchange-biased tunnel junctions Peer-reviewed

ACC Yu, XF Han, J Murai, Y Ando, T Miyazaki, K Hiraga

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　240　(1-3)　130-133　2002/02

DOI： 10.1016/S0304-8853(01)00734-X 　

ISSN： 0304-8853
Enhancement of Thermal Stability in Ferromagnetic Tunnel Junctions Prepared by the Radical Oxidation Method Peer-reviewed

S. Iura, H. Kubota, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　26　(6)　839-842　2002
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.26.839 　

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The annealing temperature dependence of the tunnel magnetore-sistance (TMR) ratio for ferromagnetic tunnel junctions prepared by various oxidation methods was measured. A junction prepared by plasma oxidation showed a TMR ratio of 31.4% before heat treatment, and this ratio increased to 49% after annealing at 300°C. On the other hand, the TMR ratio for a junction prepared by radical oxidation showed a maximum at 350°C. The enhancement of the thermal stability resulted from the different oxidation progress depending on the oxidation method.
Scanning tunneling microscopy observation of the initial state of oxidation in ferromagnetic tunnel junctions Peer-reviewed

M Hayashi, Y Ando, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　40　(12A)　L1317-L1319　2001/12

DOI： 10.1143/JJAP.40.L1317 　

ISSN： 0021-4922
Magnon excitation of CoFe/Al-oxide/CoFe ferromagnetic tunnel junctions Peer-reviewed

J Murai, Y Ando, T Daibou, K Yaoita, HF Han, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　226　922-923　2001/05

ISSN： 0304-8853
Optical and magnetic properties for metal halide-based organic-inorganic layered perovskites Peer-reviewed

E Shikoh, Y Ando, M Era, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　226　2021-2022　2001/05

ISSN： 0304-8853
Local transport properties of ferromagnetic tunnel junctions Peer-reviewed

Y Ando, M Hayashi, M Kamijo, H Kubota, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　226　924-925　2001/05

ISSN： 0304-8853
Ferromagnetic resonance linewidth for NM/80NiFe/NM films (NM = Cu, Ta, Pd and Pt) Peer-reviewed

S Mizukami, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　226　1640-1642　2001/05

ISSN： 0304-8853
Inelastic magnon and phonon excitations in Al1-xCox/Al1-xCox-oxide/Al tunnel junctions Peer-reviewed

XF Han, J Murai, Y Ando, H Kubota, T Miyazaki

APPLIED PHYSICS LETTERS　78　(17)　2533-2535　2001/04

DOI： 10.1063/1.1367882 　

ISSN： 0003-6951
Analyses of intrinsic magnetoelectric properties in spin-valve-type tunnel junctions with high magnetoresistance and low resistance Peer-reviewed

X. F. Han, A. C. C. Yu, M. Oogane, J. Murai, T. Daibou, H. Kubota, Y. Ando, T. Miyazaki

Physical Review B　2001/03
Effect of microstructure on the magnetoresistive properties of NiFe/Co(CoFe)/Al(Ta)-oxide/Co(CoFe) tunnel junctions Peer-reviewed

H Kyung, HS Ahn, CS Yoon, CK Kim, O Song, T Miyazaki, Y Ando, H Kubota

JOURNAL OF APPLIED PHYSICS　89　(5)　2752-2755　2001/03

DOI： 10.1063/1.1343519 　

ISSN： 0021-8979
The study on ferromagnetic resonance linewidth for NM/80NiFe/NM (NM = Cu, Ta, Pd and Pt) films Peer-reviewed

S Mizukami, Y Ando, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS　40　(2A)　580-585　2001/02

DOI： 10.1143/JJAP.40.580 　

ISSN： 0021-4922
Microfabrication and Magnetoelectric Properties of High-magnetoresistance Tunnel Junctions Peer-reviewed

X. F. Han, M. Oogane, T. Daibou, K. Yaoita, Y. Ando, H. Kubota, T. Miyazaki

J. Magn. Soc. Jpn.　25　(4)　707-710　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.707 　

ISSN： 0285-0192

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Spin-valve-type tunnel junctions with structure of Ta(5nm)/Ni₇₉Fe₂₁(3 nm)/Cu(20 nm)/Ni₇₉Fe₂₁(3 nm)/Ir₂₂Mn₇₈ (10 nm)/Co₇₅Fe₂₅(4 nm)/Al(0.80 nm)-oxide /Co₇₅Fe₂₅(4 nm)/Ni₇₉Fe₂₁(20 nm)/Ta(5 nm) were fabricated using a microfabrication technique. The optical lithography combined with Ar ion-beam etching and CF₄ active etching was used to pattern the junction area with the size from 100x100 down to 3x3 μm². A thinner barrier layer and a short plasma-oxidation time for Al-oxide layer were used in order to reduce the junction resistance and increase the TMR ratio. High TMR ratio of 69.1% at 4.2 K and 49.7% at room temperature were achieved. A spin-electron polarization tunneling model, based on magnon emission or absorption by the tunneling electrons during the tunnel process, was extended by defining an anisotropic wavelength cutoff energy of spin-wave in this work. Intrinsic magnetoelectric properties, such as the temperature dependence of TMR ratio and resistances from 4.2 to 300 K at 1.0 mV bias can be self-consistently evaluated using this extended model and a unique set of intrinsic parameters.
Spin-Dependent Local Transport Properties in Ferromagnetic Tunnel Junction Peer-reviewed

M. Hayashi, Y. Ando, H. Kubota, T. Miyazaki

J. Magn. Soc. Jpn　25　(4)　759-762　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.759 　

ISSN： 0285-0192

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The local electrical properties in ferromagnetic tunnel junctions was measured using contact-mode Atomic Force Microscopy (AFM). The electrical current images reflected the barrier height distribution determined by local I-V curve measurement The TMR ratio was estimated from the current histogram. The estimation closely fitted the experimental temperature dependence of TMR ratio. The TMR ratio was shown to increase with a decrease in the deviation of barrier height distribution and with an increase in average barrier height The effect of the local current channel with low barrier height on the TMR ratio is also discussed.
Fabrication of Low-Resistance Ferromagnetic Tunnel Junction Using Plasma Oxidation Peer-reviewed

K. Yaoita, M. Kamijo, T. Niizeki, T. Yamamoto, H. Kubota, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　25　(4)　771-774　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.771 　

ISSN： 0285-0192

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Ferromagnetic tunnel junctions , Ta/Ni₈₀Fe₂₀/Cu/Ni₈₀Fe₂₀/IrMn/Co₇₅Fe₂₅/Al-oxide/Co₇₅Fe₂₅/Ni₈₀Fe₂₀/Ta, were fabricated using ICP oxidation, and the detailed annealing temperature dependence of the TMR effect was investigated. Thickness of the Al layer was varied from 6.6 to 7.7 Å before oxidation, and the oxidation time was optimized for each thickness. The 1-μm² junctions were micro fabricated usinge-beam lithography. When the Al thickness was 6.6 Å, the RA decreased to 60-100 Ω·μm² and the TMR ratio became 30%. The lower the RA was, the lower the TMR ratio became.
Tunnel Magnetoresistance Effect for Double Tunnel Junctions with Al Intermediate Layer Peer-reviewed

T. Daibou, M. Oogane, Y. Ando, C. K. Kim, O. Song, T. Miyazaki

J. Magn. Soc. Jpn.　25　(4)　767-770　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.767 　

ISSN： 0285-0192

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Tunnel magnetoresistance for double barrier tunnel junctions with an intermediate layer of metallic Al was investigated. The junction with a 40-Å intermediate layer of Al showed a about 8.5%. TMR ratio. The TMR ratio decreased with increasing Al thickness and became zero at 100 Å. At a low temperature, Al thin film was expected to be in transition to superconductor. A superconducting gap was observed in the two junctions with 40-Å and 100-Å Al at about 0.4 K.
Spin Dependent Transport Properties in Ferromagnetic Double Barrier Junction Peer-reviewed

T. Siripongsakul, M. Oogane, Andrew C. C. Yu, H. Kubota, Y. Ando, T. Miyazaki, Changkyung Kim, Ohsung Song

J. Magn. Soc. Jpn.　25　(4)　763-766　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.763 　

ISSN： 0285-0192

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Ferromagnetic double barrier junctions of Co₇₅Fe₂₅/ Al₂O₃/ Co₇₅Fe₂₅(X)/ Al₂O₃/ Co₇₅Fe₂₅ with discontinuous middle Co₇₅Fe₂₅ layers (X = 0, 0.7, 1.3, 2.0 nm) were fabricated, and magnetoresistance of these junctions was measured by a dc-4-probe method. At low temperature, the resistance and TMR ratio increased rapidly. This result implies the existence of a charging effect due to the Coulomb-blockade. At temperatures below 50 K, an ac-modulation method was used to measure bias-voltage dependence of the TMR ratio. We observed an increase in TMR ratio for the case of dc transport at low bias voltage. On the other hand, the TMR ratio decreased for the case of ac transport. At high bias voltage and at high temperature, however, we observed no difference between these methods. Such transport properties could be explained by a co-tunneling process.
Magnetism and Optical Properties of Organic-Inorganic Layered Perovskites Peer-reviewed

E. Shikoh, Y. Ando, M. Era, T. Miyazaki

J. Magn. Soc. Jpn.　25　(4)　755-758　2001
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.25.755 　

ISSN： 0285-0192

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Layered perovskites (RNH₃)₂CuCl₄ were synthesized, where R was C₆H₅(CH₂)-, C₆H₅(CH₂)₂-, 1-C₁₀H₇(CH₂)-, 2-C₁₀H₇(CH₂)-, 1-C₆H₅N=NC₆H₄O(CH₂)₃- and 1-C₆H₅COC₆H₄O(CH₂)₃-. These complexes showed ferromagnetism, with different Curie temperatures, T_c, depending on the structure of the molecules. These T_c seem to be independent of the distance of interlayer space between CuCl-based layers. The complexes with naphthalene showed lower T_c than those with benzene. Since naphthalene has more π-electrons than benzene, the degree of electronic state mixing between the organic and the inorganic layers might change and affect the interlayer magnetic interaction J'.
Annealing effect on low-resistance ferromagnetic tunnel junctions Peer-reviewed

Y Ando, H Kubota, M Hayashi, M Kamijo, K Yaoita, ACC Yu, XF Han, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS　39　(10)　5832-5837　2000/10

DOI： 10.1143/JJAP.39.5832 　

ISSN： 0021-4922
Enhancement of tunnel magnetoresistance in ferromagnet/granular/ferromagnet junction related to the Coulomb blockade effect (vol 87, pg 5212, 2000) Peer-reviewed

H Kubota, Y Fukumoto, S Thamrongsing, Y Ando, T Miyazaki, CC Yu

JOURNAL OF APPLIED PHYSICS　88　(3)　1704-1704　2000/08

DOI： 10.1063/1.373881 　

ISSN： 0021-8979
Fabrication of high-magnetoresistance tunnel junctions using Co75Fe25 ferromagnetic electrodes Peer-reviewed

XF Han, M Oogane, H Kubota, Y Ando, T Miyazaki

APPLIED PHYSICS LETTERS　77　(2)　283-285　2000/07

DOI： 10.1063/1.126951 　

ISSN： 0003-6951
Local current distribution in a ferromagnetic tunnel junction measured using conducting atomic force microscopy Peer-reviewed

Y Ando, H Kameda, H Kubota, T Miyazaki

JOURNAL OF APPLIED PHYSICS　87　(9)　5206-5208　2000/05

DOI： 10.1063/1.373296 　

ISSN： 0021-8979
High-magnetoresistance tunnel junctions using Co75Fe25 ferromagnetic electrodes Peer-reviewed

XF Han, T Daibou, M Kamijo, K Yaoita, H Kubota, Y Ando, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　39　(5B)　L439-L441　2000/05

DOI： 10.1143/JJAP.39.L439 　

ISSN： 0021-4922
Magnon-assisted inelastic excitation spectra of a ferromagnetic tunnel junction Peer-reviewed

Y Ando, J Murai, H Kubota, T Miyazaki

JOURNAL OF APPLIED PHYSICS　87　(9)　5209-5211　2000/05

DOI： 10.1063/1.373297 　

ISSN： 0021-8979
Enhancement of tunnel magnetoresistance in ferromagnet/granular/ferromagnet junction related to the Coulomb blockade effect Peer-reviewed

H Kubota, Y Fukumoto, S Thamrongsing, Y Ando, T Miyazaki, C Yu

JOURNAL OF APPLIED PHYSICS　87　(9)　5212-5214　2000/05

DOI： 10.1063/1.373298 　

ISSN： 0021-8979
Effect of particle size on the magnetization process in lithographic arrays of Nd2Fe14B Peer-reviewed

H Kubota, T Ikari, Y Ando, H Kato, T Miyazaki

JOURNAL OF APPLIED PHYSICS　87　(9)　6325-6327　2000/05

DOI： 10.1063/1.372694 　

ISSN： 0021-8979

eISSN： 1089-7550
Reduction of Resistance and Annealing Effect in Ferromagnetic Tunnel Junctions

KAMIJO M., MURAI J., KUBOTA H., ANDO Y., MIYAZAKI T., KIM Changkung, SONG Ohsung

Journal of the Magnetics Society of Japan　24　(4)　591-594　2000/04/15
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.591 　

ISSN： 0285-0192

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Ferromagnetic tunnel junctions of Ta/Al/Ta/Ni₈₀Fe₂₀/IrMn/Co/Al-oxide/Co/Ni₈₀Fe₂₀/Ta/Cu with various Al-oxide thicknesses were fabricated by rf magnetron sputtering and ICP oxidization. The thickness of Al was varied from 6 Å to 13 Å. With decreasing thickness, the tunnel resistance decreased from 3 x 10⁵ Ω·μm² to 1.2 x 10²Ω·μm². At Al thicknesses of 13 and 10 Å, the MR ratio was 22%-20%, and increased to 35%-30% after annealing. In other junctions, the MR ratios were small and increased only slightly after annealing, the I-V curves of all junctions were asymmetric before annealing. The curves were analyzed by taking account of both barrier heights φ₁ and φ₂ (upper and lower interfaces). The difference between φ₁ and φ₂ was reduced by annealing, and the MR ratio became large at φ₁ = φ₂.
Magnon Excitation at the Interface of Co/Al/Al-Oxide/Co Tunnel Junctions Peer-reviewed

J. Murai, Y. Ando, M. Kamijo, T. Daibou, H. Kubota, T. Miyazaki, C. Kim, O. Song

J. Magn. Soc. Jpn.　24　(4_2)　615-618　2000/04
Local Transport Properties and magnetoresistive Effects of Ferromagnetic Tunneling Junctions Peer-reviewed

Y. Ando, H. Kameda, M. Hayashi, H. Kubota, T. Miyazaki

J. Magn. Soc. Jpn.　24　(4_2)　611-614　2000/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.611 　

ISSN： 0285-0192

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The local electrical properties were measured simultaneously with the topography for a Ta(50Å)/Fe₂₀Ni₈₀(50Å)/IrMn(150Å)/Co(50Å)/Al(d_AlÅ)-oxide junction. The electrical image showed the contrast with a lateral size of around a few nm, and no strong correlation with the topography was observed. By analyzing the local current-voltage characteristics, we found that the contrast of the current image showed the distribution of the barrier height. This may be due to the lack of the oxygen from the stoichiometry of the Al₂O₃ composition. We measured the current images for junctions with shorter oxidation times and with lower Al thicknesses. The histogram of current densities was calculated by taking into consideration the Gaussian distribution of the barrier height. It fitted the experimental results well except for the junction with thin Al; this may be due to a local leakage current. The tunneling magnetoresistance (TMR) ratio was considered to be reduced by this current.
Tunnel Magnetoresistance Effect for Ni⁸⁰Fe²⁰/Co/N(N=Ta, Cu, Al)/Ai-oxide/Co Junctions Peer-reviewed

T. Daibou, N. Tezuka, H. Kubota, Y. Ando, M. Hayashi, T. Miyazaki, C. Kim, O. Song

J. Magn. Soc. Jpn.　24　(4_2)　599-602　2000/04

DOI： 10.3379/jmsjmag.24.599 　
Characterization of the Barrier Layer in Al_1-xCo_x/(Al_1-xCo_x-oxide)/Al Junctions Peer-reviewed

X. F. Han, J. Murai, M. Hayashi, N. Tezuka, H. Kubota, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　24　(4-2)　603-606　2000/04

DOI： 10.3379/jmsjmag.24.603 　
Magnetism and the Optical Properties of Organic Ammonium-3d Transition Metal Complexes Peer-reviewed

E. Shikoh, Y. Ando, M. Era, T. Miyazaki

J. Magn. Soc. Jpn.　24　(4_2)　491-494　2000
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.491 　

ISSN： 0285-0192

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Organic-inorganic complex magnets ((RNH₃)₂MX₄) were synthesized, where R is a simple alkylammonium molecule (CH₃(CH₂)₁₇), a 1-methy1-naphthalene (C₁₀H₉CH₂), a 1-pro-pyl-naphthalene (C₁₀H₉O(CH₂)₃), or a 1-buty1-naphthalene (C₁₀H₉O(CH₂)₄), M is a 3d transition metal element, and X is a halide element (Cl). Their complexes had a layered perovskite structure checked by XRD. The distance of interlayer space between MCl-based layers was shorter for the complexes with 1-buty1-naphthalene than for those with 1-propy1-naphthalene. When R was a simple alkylammonium molecule, a 1-methy1-naphthalene and a 1-propy1-naphthalene, its Cu complexes showed ferromagnetism and its Mn complexes antiferromagnetism. How-ever, Cu and Mn complexes with a 1-buty1-naphthalene did not show ferromagnetism and antiferromagnetism, respectively. The absorption spectra of Cu complexes were also measured. When R was a simple alkylammonium molecule, a 1-methy1-naphthalene, and a 1-propy1-naphthalene, Cu complexes showed a D_4th structure for inorganic layers, while the structure for the complex with a 1-buty1-naphthalene was D_2d.
Thickness and Oxidation Time Dependence of Tunnel Magnetoresistance in Ni-Fe/Co/Al-O/Co Junctions Peer-reviewed

H. Kubota, S. Otsuka, M. Kamijo, N. Tezuka, Y. Ando, C. C. Yu, T. Miyazaki

J. Magn. Soc. Jpn.　24　(4_2)　595-598　2000
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.595 　

ISSN： 0285-0192

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Ni-Fe/Co/Al-O/Co tunnel junctions with small active areas down to 3 x 3 μm² were fabricated by the micro-fabrication technique. The Al-O insulating layer was prepared by plasma oxidation of a thin sputtered Al film. The dependences of the tunnel magnetoresistance on the thickness of the Al film and the oxidation time were investigated. The interface structure of the junction was observed by using high-resolution electron microscopy. The relationship between the magnetoresistive properties and the interface structure is discussed.
Magnetoresistance Effect in Ferromagnetic Tunnel Junctions with Ultra Thin Al-O Films Prepared by Plasma Oxidation Peer-reviewed

M. Kamijo, J. Murai, H. Kubota, Y. Ando, T. Miyazaki, C. Kim, O. Song

J. Magn. Soc. Jpn.　24　(4_2)　591-594　2000

DOI： 10.3379/jmsjmag.24.591 　
Ni₈₀Fe₂₀薄膜における強磁性共鳴線幅の下地層依存性 Peer-reviewed

水上成美, 安藤康夫, 宮﨑照宣

日本応用磁気学会誌　24　(4_2)　535-538　2000

DOI： 10.3379/jmsjmag.24.535 　
Direct observation of magnon excitation in a ferromagnetic tunnel junction using inelastic-electron-tunneling spectroscopy Peer-reviewed

J Murai, Y Ando, M Kamijo, H Kubota, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　38　(10A)　L1106-L1108　1999/10

DOI： 10.1143/JJAP.38.L1106 　

ISSN： 0021-4922
Enhancement of tunnel magnetoresistance effect on junction with Co cluster layers in Coulomb blockade regime Peer-reviewed

Y Fukumoto, H Kubota, Y Ando, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　38　(8B)　L932-L934　1999/08

DOI： 10.1143/JJAP.38.L932 　

ISSN： 0021-4922
Magnetic properties of ferrocenylmethylacrylate-N-dodecylacryl-amide copolymer Langmuir-Blodgett films Peer-reviewed

Y Ando, T Hiroike, T Miyashita, T Miyazaki

THIN SOLID FILMS　350　(1-2)　232-237　1999/08

DOI： 10.1016/S0040-6090(99)00271-0 　

ISSN： 0040-6090
Local transport property on ferromagnetic tunnel junction measured using conducting atomic force microscope Peer-reviewed

Y Ando, H Kameda, H Kubota, T Miyazaki

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　38　(7A)　L737-L739　1999/07

DOI： 10.1143/JJAP.38.L737 　

ISSN： 0021-4922
Influence of interlayer roughness on magnetoresistive effect of ferromagnetic tunneling junctions Peer-reviewed

Y Ando, M Yokota, N Tezuka, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　198-99　155-157　1999/06

DOI： 10.1016/S0304-8853(98)01053-1 　

ISSN： 0304-8853
Analysis of the interface in ferromagnet insulator junctions by inelastic-electron-tunneling-spectroscopy Peer-reviewed

Y Ando, J Murai, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　198-99　161-163　1999/06

DOI： 10.1016/S0304-8853(98)01050-6 　

ISSN： 0304-8853
Magnetoresistive Effect in Ferromagnetic Tunneling Junctions Fabricated from Wedge-Shaped Aluminum Peer-reviewed

Y. Ando, M. Yokota, T. Miyazaki

J. Magn. Soc. Jpn.　23　(4_2)　1285-1288　1999/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.1285 　

ISSN： 0285-0192

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Ferromagnetic tunneling 80NiFe/Co/Al oxide/Co junctions with various Al oxide thicknesses were fabricated. To prepare Al oxide, a wedge-shaped piece of pure Al was sputtered without exposure to air. The surface roughness of the unexposed samples was quite small, while that of a sample with an air-leak tended to grow larger with increasing oxidization time and also d_Al. The tunneling magnetoresistive effect (TMR) was observed at an Al thickness of about 9 Å for exposed junctions. Below this thickness, the barrier height estimated from the I-V curve decreased. On the other hand, the barrier height and thickness were roughly constant for junctions with d_Al>9 Å. This indicated that the metallic Al could exist, causing a reduction in the TMR.
Analysis of the Interface in Al/Al-Oxide/ M/Al (M=Fe, Ni) Junctions by Inelastic-Electron-Tunneling Spectroscopy Peer-reviewed

J. Murai, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　23　(4_2)　1325-1328　1999/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.1325 　

ISSN： 0285-0192

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Inelastic-electron-tunneling spectroscopy (IETS) was used to investigate the electron states of the interfaces of Al/Al-oxide/Fe(d_Fe)/Al and Al/Al-oxide/Ni(d_Ni)/Al tunnel junctions. The conductance curves for all junctions showed a minimum around the zero-bias voltage. The IET spectra showed a strong positive peak around 4 mV, corresponding to the minimum of conductance curves, while another broad peaks was observed for junctions with d_Ni, d_Fe≥10Å, The peak position was different from that assigned to the Al-O LO phonon mode observed for Al/Al-oxide/Al junctions. It was confirmed by magnetization measurements that a ferromagnetic layer was formed for films with d_Ni≥30Å and d_Fe≥10Å. These results were investigated in relation to the direct and inelastic tunneling process due to magnons.
Thickness Dependence of Ferromagnetic Resonance for Co and Ni₈₀Fe₂₀ Thin Films Peer-reviewed

S. Mizukami, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　23　(4_2)　1173-1176　1999/04
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.1173 　

ISSN： 0285-0192

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Thickness dependence of ferromagnetic resonance (FMR) and magnetic properties were studied for cobalt and Ni₈₀Fe₂₀ thin films prepared on glass substrates by magnetron, sputtering. Resonance field and linewidth increased with decreasing film thickness, while saturation magnetization and square ratio decreased. Thickness dependence of 4πM_eff. estimated from resonance field by using Kittel's formula was consistent with 4πM_s from hysteresis loops. Linewidth was assumed to have two components: zero-frequency linewidth, ΔH₀, caused by magnetic inhomogeneities in films and viscous damping. ΔH₀ estimated from the experimental linewidth was, above 40 Å thick, nearly constant with film thickness. Below 30 Å, however, ΔH₀ for both films rapidly increased. These results were discussed by taking account of the structural inhomogeneity in the thin magnetic layer region.
Synthesis and the Magnetism of the Metal Halide-based Organic/Inorganic Layered Perovskite Peer-reviewed

Y. Ando, E. Shikoh, T. Miyazaki

J. Magn. Soc. Jpn.　23　(1_2)　596-598　1999/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.596 　

ISSN： 0285-0192

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Metal halide-based layered perovskites, (RNH₃)₂MCl₄, self-organized organic/inorganic multilayer structure were synthesized, where R is a simple alkylammonium molecule with a long chain length, (CH₃(CH₂)₁₇) or a l-methyl-naphthalene (C₁₀H₉CH₂), M is 3d transition metal elements. Its layered pcrovskite structure was checked by a FT-IR method. The perovskites of CH₃(CH₂)₁₇NH₃ with Cu and Cr showed ferromagnetism (T_C= 10 K and 42 K, respectively), and Mn and Fe antifcrromagnetism (T_N=41 K and 95 K, respectively). These results roughly corresponded to the results for methyl and ethyl ammonium complexes reported. The naphthlene complex with Cu also showed ferromagnetism, however, the Curie temperature became low. It was considered that the relative large chromophore might disturb the Jahn-Teller distortion of CuCl₆ octahedra. l-methyl-naphthylamine- hydrochloride was luminous with the wavelength of 350 nm under ultraviolet light irradiation, but its Cu complex was quenched.
Analysis of the Interlayer in Al/Al₂O_3//Co/Al Junction by Inelastic-Electron-Tunneling-Spectroscopy Peer-reviewed

J. Murai, Y. Ando, T. Miyazaki

J. Magn. Soc. Jpn.　23　(1_2)　64-66　1999/01
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.64 　

ISSN： 0285-0192

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Inelastic-Electron-Tunneling-Spectroscopy (IETS) has been applied to investigate the electron states of the interface of Al/Al₂O₃/Co(d_Co)/Al tunneling junctions. A zero-bias anomaly was observed in the conductance curve of the junction with d_Co of 2 Å and decreased with increasing d_Co. The IET spectra of these junctions showed a strong negative peak at 4 mV, corresponding to the zero- bias anomaly, while the another broad peak was observed for the junctions with d_Co ≥10Å. The peak was different in the position from that assigned to the Al-O LO phonon mode observed for Al/Al₂O₃/Al junction. From the magnetization measurement, it is confirmed that the ferromagnetic layer was formed for the junctions with d_Co ≥10 Å These results were discussed with the paramagnetic impurity and magnon assisted tunneling process.
Magnetic properties of random-anisotropy amorphous magnets (RxFe1-x)(80)Si12B8 with R = Pr, Nd, Sm, Tb, Dy and Er Peer-reviewed

H Kato, N Kurita, Y Ando, T Miyazaki, M Motokawa

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　189　(3)　263-273　1998/11

DOI： 10.1016/S0304-8853(98)00285-6 　

ISSN： 0304-8853
Spin dependent tunneling in 80NiFe/LB film with ferrocene and tris(bipyridine)ruthenium derivatives Co junctions Peer-reviewed

Y Ando, J Murai, T Miyashita, T Miyazaki

THIN SOLID FILMS　331　(1-2)　158-164　1998/10

DOI： 10.1016/S0040-6090(98)00913-4 　

ISSN： 0040-6090
Spin-polarized magnetic tunnelling magnetoresistive effects in various junctions Peer-reviewed

T Miyazaki, N Tezuka, S Kumagai, Y Ando, H Kubota, J Murai, T Watabe, M Yokota

JOURNAL OF PHYSICS D-APPLIED PHYSICS　31　(6)　630-636　1998/03

DOI： 10.1088/0022-3727/31/6/009 　

ISSN： 0022-3727
Analysis of the Interlayers in a Ferromagnet/ Insulator Junction by Inelastic Electron-Tunneling Spectroscopy Peer-reviewed

J. Murai, Y. Ando, N. Tezuka, T. Miyazaki

J. Magn. Soc. Jpn.　22　(4)　573-576　1998
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.22.573 　

ISSN： 0285-0192

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Inelastic electron-tunneling spectroscopy (IETS) has been used to investigate the vibrational spectrum in Al/Al₂O₃/CO/AI tunneling junctions with various Co thicknesses (d _Co). A zero-bias anomaly was observed in the conductance curve of the junction with d_Co of 2Å, and decreased with increasing d_Co. The IET spectra of these junctions showed strong negative peaks at 4 mV, corresponding to the zero-bias anomaly, while phonon spectra were observed for the junction with d_Co ≥ 10Å. The peak position was different from that of Al/Al₂O₃/Al. After annealing of the junction with d_Co of 2Å at 250°C for one hour, the zero-bias anomaly decreased and the phonon spectrum appeared.
Magnetoresistive Effect in Ferromagnetic Tunneling Junctions with Wedge-Shaped Al-O Insulator Peer-reviewed

M. Yokota, Y. Ando, N. Tezuka, T. Miyazaki

J. Magn. Soc. Jpn.　22　(4)　569-572　1998
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.22.569 　

ISSN： 0285-0192

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Ferromagnetic tunneling junctions of Ni₈₀Fe₂₀ (Py)/Co/Al oxide/Co with wedge-shaped insulators were fabricated. Al oxide films were formed by natural oxidization with various conditions and were checked by FT-IR spectroscopy. The peak intensity and the position depending on the Al thickness were explained by using the 1-D Einstein model. When the oxidization time was less than 50 h, tunneling magnetoresistance (TMR) was observed at about 13 Å of the Al thickness. When the oxidization time became more than 50 h, the thickness shifted to less than 10 Å. The reason for this was considered that Co oxide was formed on the surface of the bottom electrode and became a tunneling barrier with increasing oxidization time. On the other hand, the TMR decreased rapidly with increasing Al thickness. To determine the reason for this, AFM images of the Py/Co/Al surface with various oxidization times were measured. The surface roughness of the Al increased with increasing oxidization time, corresponding to the TMR results.
Exchange coupling energy determined by ferromagnetic resonance in 80Ni-Fe/Cu multilayer films Peer-reviewed

Y Ando, H Koizumi, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　166　(1-2)　75-81　1997/02

DOI： 10.1016/S0304-8853(96)00413-1 　

ISSN： 0304-8853
Influence of Molecular Structure on the Tunneling Magnetoresistive Effect in Ferromagnet-Molecular Junctions Peer-reviewed

Y.Ando, J.Murai, T.Miyazaki

J. Magn. Soc. Jpn.　21　(4)　497-500　1997
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.21.497 　

ISSN： 0285-0192

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Ferromagnet/insulator/ferromagnet junctions with Langmuir-Blodgett (LB) films were fabricated. The LB films used were poly-N-dodecylacrylamide (PDDA) and merocyanine (MC) dye. A magnetoresistance ratio of 0.3% at 300 K was observed in the junction with PDDA. This value was small in comparison with the theoretical values. One possible reason for this was the presence of an inelastic tunnel with a molecular vibration. To confirm this possibility, inelastic tunnel spectroscopy was performed. A shift of the peak assigned to the C=O stretching vibration was observed, indicating that electrons are trapped at the carbonyl group and can tunnel between the electrode and the carbonyl group. The junction with MC did not show the magnetic tunneling effect. MC relaxed rapidly to spiropyran (SP) form on the water surface, and the homogeneity of the LB film was lost.
Ferromagnetic Resonance (FMR) Study of 70CoNi/Cu/80NiFe Trilayers and 70CoNi/Cu/80NiFe/Cu/70CoNi Five-Layers Peer-reviewed

S.Mizukami, Y.Ando, T.Miyazaki

J. Magn. Soc. Jpn.　21　(4)　445-448　1997
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.21.445 　

ISSN： 0285-0192

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Interlayer exchange-coupling strength, J, was studied by measuring the ferromagnetic resonance (FMR) of 70CoNi/ Cu/80NiFe trilayers and 70CoNi/Cu/80NiFe/Cu/70CoNi five-layers prepared on glass substrates by magnetron sputtering. In the trilayers, J oscillated between positive and negative values a function of the spacer Cu layer thickness, and two peaks as in the negative value of J were observed. In the five-layers, on the other hand, two values of J were observed. One of those corresponded to J in the trilayers, while the other was positive and decreased monotonically with increasing the Cu spacer layer thickness. These results are consistent with that for the magnetoresistance.
Relationship between the Barrier and Magnetoresistance Effect in Ferromagnetic Tunneling Junctions Peer-reviewed

N.Tezuka, Y.Ando, T.Miyazaki

J. Magn. Soc. Jpn.　21　(4)　493-496　1997
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.21.493 　

ISSN： 0285-0192

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The dependence of the tunneling magnetoresistive effect on the barrier height was investigated. The magnitude of the barrier height increased with increasing aluminum oxidation temperature and time from 0.3 to 2.3 eV in Fe/Al oxide/Fe junctions. However, those values are smaller than those reported for an Al₂O₃ barrier. A possible reason for this is that the barrier is not pure Al₂O₃, but AIO_x, or another oxide created by interface mixing between Fe and Al oxide. On the other hand, the magnetoresistance ratio in these junctions varied up to 18% at room temperature and up to 18% at 4.2 K. The dependence of the magnetoresistance ratio at 4.2 K on the barrier height is roughly the same as predicted by Slonczewski's theory. This result shows that the effective spin polarization of ferromagnetic electrodes changes according to the barrier height.
Ferromagnetic resonance in 80Ni-Fe/Cu/Co multilayer films Peer-reviewed

H Koizumi, Y Ando, T Miyazaki

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　164　(3)　293-299　1996/12

DOI： 10.1016/S0304-8853(96)00418-0 　

ISSN： 0304-8853
Magnetic properties of stearate films with 3d transition metal ions fabricated by the Langmuir-Blodgett method Peer-reviewed

Y Ando, T Hiroike, T Miyashita, T Miyazaki

THIN SOLID FILMS　278　(1-2)　144-149　1996/05

DOI： 10.1016/0040-6090(95)08146-1 　

ISSN： 0040-6090
Magnetic properties of polymer LB films containing ferrocene derivatives Peer-reviewed

Y Ando, T Hiroike, T Miyazaki, A Aoki, T Miyashita

MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS　285　411-416　1996

ISSN： 1058-725X
Magnetic Properties of Polymer LB Films Containing Ferrocene Derivatives Peer-reviewed

Y.Ando, T.Hiroike, A.Aoki, T.Miyashita, T.Miyazaki

Mol. Cryst. Liq. Cryst.　286　89-94　1996
FABRICATION OF FERROUS STEARATE MULTILAYER FILMS BY THE LANGMUIR-BLODGETT METHOD Peer-reviewed

Y ANDO, T HIROIKE, T MIYASHITA, T MIYAZAKI

THIN SOLID FILMS　266　(2)　292-297　1995/10

DOI： 10.1016/0040-6090(95)06731-0 　

ISSN： 0040-6090
Magnetic Properties of Rapidly Quenched (Gd-M)₈₀Si ₁₂B₈ Amorphous Alloys Peer-reviewed

N. Kurita, Y. Ando, S. Ishio, T. Miyazaki

J. Magn. Soc. Jpn.　18　231-234　1995

DOI： 10.3379/jmsjmag.18.231 　
強磁性/Al₂O₃/強磁性接合の磁気トンネリング効果 Peer-reviewed

手束展規, 安藤康夫, 宮崎照宣

J. Magn. Soc. Jpn.　19　(2)　369-372　1995

DOI： 10.3379/jmsjmag.19.369 　
80Ni-Fe/Cu/Co三層膜における強磁性共鳴 Peer-reviewed

古泉浩, 久保田均, 安藤康夫, 石尾俊二, 宮崎照宣

J. Magn. Soc. Jpn.　19　(2)　389-392　1995

DOI： 10.3379/jmsjmag.19.389 　
MAGNETIC PROPERTIES OF ORGANIC MULTILAYER FILMS FABRICATED BY LANGMUIR-BLODGETT METHOD. Peer-reviewed

Y.Ando, T.Hiroike, A.Aoki, T.Miyashita, T.Miyazaki

Proceedings of the Third International Symposium on Physics of Magnetic Materials　40-44　1995
HIGH FIELD MAGNETIZATION AND MOSSBAUER ABSORPTION IN (R_XFe_1-X)₈₀Si₁₂B₈ AMORPHOUS ALLOYS (R-Pr,Nd,Sm,Tb,Dy AND Er) Peer-reviewed

N.Kurita, H.Kato, Y.Ando, T.Miyazaki

Proceedings of the Third International Symposium on Physics of Magnetic Materials　805-808　1995
LINEAR AC MAGNETIC RESPONSE NEAR THE VORTEX-GLASS TRANSITION IN SINGLE-CRYSTALLINE YBA2CU3O7 Peer-reviewed

Y ANDO, H KUBOTA, Y SATO, TERASAKI, I

PHYSICAL REVIEW B　50　(13)　9680-9683　1994/10

DOI： 10.1103/PhysRevB.50.9680 　

ISSN： 0163-1829
Magnetic Properties of Rapidly Quenched (Gd-M)<inf>80</inf>Si<inf>12</inf>B<inf>8</inf> Amorphous Alloys Peer-reviewed

N. Kurita, Y. Ando, T. Miyazaki

IEEE Translation Journal on Magnetics in Japan　9　(6)　185-190　1994

DOI： 10.1109/TJMJ.1994.4565978 　

ISSN： 0882-4959
FMR Study of Ni-Fe/Cu Multilayer Films Peer-reviewed

H. Koizumi, M. Sato, Y. Ando, T. Miyazaki

IEEE Translation Journal on Magnetics in Japan　9　(6)　242-246　1994

DOI： 10.1109/TJMJ.1994.4565987 　

ISSN： 0882-4959
FMR Study of Ni-Fe/Cu Multilayer Films Peer-reviewed

H. Koizumi, M. Sato, Y. Ando, S. Ishio, T. Miyazaki

J. Magn. Soc. Jpn.　18　361-364　1994

DOI： 10.3379/jmsjmag.18.361 　
FMR STUDY ON PERMALLOY/CU/PERMALLOY TRILAYER FILMS FABRICATED ON CU BUFFER LAYERS Peer-reviewed

S ISHIO, H KOIZUMI, H KUBOTA, Y ANDO, T MIYAZAKI

PHYSICA STATUS SOLIDI A-APPLIED RESEARCH　139　(2)　K125-K128　1993/10

DOI： 10.1002/pssa.2211390239 　

ISSN： 0031-8965
SIZE EFFECT IN THE VORTEX-GLASS TRANSITION IN SUBMICRON YBA2CU3OY STRIPS - EVIDENCE FOR SOFTENING OF VORTEX MATTER Peer-reviewed

Y ANDO, H KUBOTA, S TANAKA

PHYSICAL REVIEW LETTERS　69　(19)　2851-2854　1992/11

ISSN： 0031-9007
重層媒体におけるビデオ信号の磁気記録シミュレ-ション解析 Peer-reviewed

安藤康夫, 田河育也, 中村慶久

テレビジョン学会誌　46　(10)　1286-1294　1992/10
Publisher: The Institute of Image Information and Television Engineers
DOI： 10.3169/itej1978.46.1286 　

ISSN： 0386-6831

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We incorporate a magnetization model into the finite element method to calculate the recording characteristics for a VTR signal. The fact that calculated results agree with measured ones shows that this method is effective in the analysis of VTR signal recording. In addition we use the Fourier transfer to analyze magnetization distribution. This analysis clearly shows that the appearance of a spurious signal is caused by a nonlinear magnetization process. We also show that a video luminance signal can be recorded on a medium surface and that a video chrominance signal can be recorded on the middle layer of a medium. Therefore, a double-layered medium having a high coercive force in the surface layer and a low coercive force in the underlayer, is effective for the recording of a signal with a wide frequency region. Moreover, a double-layered medium with a perpendicularly oriented surface is excellent for high density recording.
Magnetic Recording Properties of Double Layered Coating Media Peer-reviewed

安藤康夫, 川上晃, れん理英子, 西川卓男

J. Magn. Soc. Jpn.　15　109-112　1991

DOI： 10.3379/jmsjmag.15.109 　
A SIMULATION FOR VIDEO SIGNAL RECORDING ON DOUBLE LAYERED COATING MEDIA . Peer-reviewed

Y.Ando, I.Tagawa, Y.Nakamura

J. Magn. Soc. Jpn.　15　(S2)　215-220　1991
CLASSICAL AND RE-ENTRANT SPIN-GLASS BEHAVIOR IN AMORPHOUS (FE1-XVX)77SI10B13, (FE1-XCRX)77SI10B13, (FE1-XMNX)77SI10B13, (FE1-XNIX)77SI10B13 ALLOYS Peer-reviewed

T MIYAZAKI, OKAMOTO, I, Y ANDO, M TAKAHASHI

JOURNAL OF PHYSICS F-METAL PHYSICS　18　(7)　1601-1610　1988/07

ISSN： 0305-4608
CLASSICAL AND RE-ENTRANT SPIN-GLASS BEHAVIOR IN AMORPHOUSFe_1-xM_x)₇₇Si₁₀B₁₃ (M=Cr,Mn,Ni) ALLOY. Peer-reviewed

T.Miyazaki, I.Okamoto, Y.Ando, M.Takahashi

Journal of Physics F Metallic Physics　18　1601-1610　1988

DOI： 10.1088/0305-4608/18/7/026 　
MAGNETIZATION AND MOSSBAUER-EFFECT INVESTIGATIONS IN AMORPHOUS (FE1-XMNX)77SI10B13 ALLOYS Peer-reviewed

T MIYAZAKI, K YAMADA, Y ANDO, OKAMOTO, I, M TAKAHASHI

IEEE TRANSACTIONS ON MAGNETICS　23　(5)　3584-3586　1987/09

ISSN： 0018-9464
LOW-FIELD MAGNETIZATION AND MOSSBAUER-EFFECT INVESTIGATIONS IN (FE65NI35)1-X(FE84MN16)X ALLOYS Peer-reviewed

T MIYAZAKI, Y ANDO, M TAKAHASHI

PHYSICAL REVIEW B　34　(9)　6334-6340　1986/11

DOI： 10.1103/PhysRevB.34.6334 　

ISSN： 0163-1829
ANOMALOUS TEMPERATURE-DEPENDENCE OF MAGNETIZATION IN SINGLE-CRYSTAL FE65NI35 ALLOY Peer-reviewed

T MIYAZAKI, Y ANDO, M TAKAHASHI

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　60　(2-3)　227-235　1986/08

ISSN： 0304-8853
ANOMALOUS TEMPERATURE-DEPENDENCE OF MAGNETIZATION IN POLYCRYSTALLINE FE65NI35 ALLOY Peer-reviewed

T MIYAZAKI, Y ANDO, M TAKAHASHI

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　60　(2-3)　219-226　1986/08

DOI： 10.1016/0304-8853(86)90104-6 　

ISSN： 0304-8853
ANOMALOUS TEMPERATURE-DEPENDENCE OF MAGNETIZATION IN POLYCRYSTALLINE FE65NI35 ALLOY Peer-reviewed

T MIYAZAKI, Y ANDO, M TAKAHASHI

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　60　(2-3)　219-226　1986/08

DOI： 10.1016/0304-8853(86)90105-8 　

ISSN： 0304-8853
SPIN-GLASS IN FE-NI INVAR-ALLOYS Peer-reviewed

T MIYAZAKI, Y ANDO, M TAKAHASHI

JOURNAL OF APPLIED PHYSICS　57　(8)　3456-3458　1985

DOI： 10.1063/1.335075 　

ISSN： 0021-8979

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Misc. 145

Recent progress of bio-magnetic field measurement by TMR sensors

大兼幹彦, 大兼幹彦, 藤原耕輔, 菅野彰剛, 中野貴文, 我妻宏, 有本直, 水上成美, 水上成美, 熊谷静似, 松崎斉, 松崎斉, 中里信和, 安藤康夫, 安藤康夫

応用物理学会春季学術講演会講演予稿集(CD-ROM)　70th　2023

ISSN： 2436-7613
Sub-pT magnetic field detection by tunnel magneto-resistive sensors

大兼幹彦, 大兼幹彦, 藤原耕輔, 菅野彰剛, 中野貴文, 我妻宏, 有本直, 水上成美, 水上成美, 熊谷静似, 松崎斉, 松崎斉, 中里信和, 安藤康夫, 安藤康夫

応用物理学会春季学術講演会講演予稿集(CD-ROM)　70th　2023

ISSN： 2436-7613
頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学(Web)　49　(5)　2021

ISSN： 2188-031X
TMRセンサの原理と心磁図計測

大兼幹彦, 大兼幹彦, 大兼幹彦, 菅野彰剛, 藤原耕輔, 中野貴文, 熊谷静似, 松崎斉, 中里信和, 安藤康夫

臨床神経生理学(Web)　49　(5)　2021

ISSN： 2188-031X
頭皮上に密着可能なトンネル磁気抵抗素子を用いた室温脳磁計の開発

菅野彰剛, 大兼幹彦, 藤原耕輔, 柿坂庸介, 松崎斉, 安藤康夫, 中里信和

臨床神経生理学(Web)　49　(5)　2021

ISSN： 2188-031X
Real-time magnetocardiographic measurement using tunnel magneto-resistive sensors

大兼幹彦, 菅野彰剛, 藤原耕輔, 松崎斉, 中里信和, 安藤康夫

日本生体医工学会大会プログラム・抄録集(Web)　60th　2021
Measurement of somatosensory evoked magnetic fields at room temperature using a tunnel magneto-resistive sensor system

菅野彰剛, 大兼幹彦, 藤原耕輔, 松崎斉, 安藤康夫, 中里信和

日本生体磁気学会誌　34　(1)　2021

ISSN： 0915-0374
スピントロニクス技術を応用した高感度生体磁気センサ技術 Invited

ANDO Yasuo

機能材料　38　40-47　2018
Anisotropic magnetic property of nanocomposite Nd<inf>2</inf>Fe<inf>14</inf>B/Mo/α-Fe multilayer films

K. Kobayashi, D. Ogawa, K. Koike, H. Kato, M. Oogane, T. Miyazaki, Y. Ando, M. Itakura

Journal of Physics: Conference Series　903　2017/10/28

DOI： 10.1088/1742-6596/903/1/012015 　

ISSN： 1742-6588
Spintronics Materials and Devices for Working Memory Technology FOREWORD

Hideo Ohno, Masafumi Yamamoto, Tetsuo Endoh, Yasuo Ando, Takahiro Hanyu, Kohei M. Itoh, Masaaki Tanaka, Seiji Mitani, Hitoshi Wakabayashi

JAPANESE JOURNAL OF APPLIED PHYSICS　56　(8)　2017/08

DOI： 10.7567/JJAP.56.080201 　

ISSN： 0021-4922

eISSN： 1347-4065
Development of High-Resolution TMR Sensor Device for Application of Bio-Magnetic Field Measurement

212　33-38　2017/02/21
Publisher: 日本磁気学会
ISSN： 1882-2940
強磁性トンネル磁気抵抗素子センサ Invited

ANDO Yasuo

電気学会誌　136　22-25　2016
Development and perspective of the highly sensitive magnetic sensors with ferromagnetic tunnel junctions

203　21-30　2015/07/24
Publisher: 日本磁気学会
ISSN： 1882-2940
Systematic investigation on correlation between sensitivity and nonlinearity in magnetic tunnel junction for magnetic sensor.

T. Nakano, M. Oogane, H. Naganuma, Y. Ando

2015 IEEE MAGNETICS CONFERENCE (INTERMAG)　2015
Temperature Dependence of Low Frequency Noise in Magnetic Tunneling Junctions with Co40Fe40B20/Co70.5Fe4.5Si15B10 Composed Free Layer.

Z. Yuan, J. Feng, P. Guo, T. Nakano, S. Ali, X. Han, H. Naganuma, Y. Ando

2015 IEEE MAGNETICS CONFERENCE (INTERMAG)　2015
Coercivity Enhancement in la Coated Nd-Fe-B Thin Films

Kunihiro Koike, Hiroya Ishikawa, Daisuke Ogawa, Hiroaki Kato, Takamichi Miyazaki, Yasuo Ando, Masaru Itakura

Physics Procedia　75　1294-1299　2015/01/01

DOI： 10.1016/j.phpro.2015.12.144 　

ISSN： 1875-3884
Spintronics technology and device development

Yasuo Ando

Jpn. J. Appl. Phys.　54　070101-1-070101-10　2015

DOI： 10.7567/JJAP.54.070101 　
界面装飾した強磁性トンネル接合の作製と磁気抵抗効果

安藤康夫, 大兼幹彦, 永沼博

東北大学極低温科学センターだより　(15)　3-6　2014/11
Publisher: 東北大学極低温科学センター
スピントロニクス技術とデバイス開発 Invited

安藤康夫

応用物理　83　(3)　184-193　2014
Publisher: 応用物理学会
ISSN： 0369-8009
磁気抵抗素子センサを用いた生体磁場計測 Invited

安藤康夫, 西川卓男

検査技術　6　2014
技術シーズを活用した研究開発テーマの発掘

安藤康夫

（株）技術情報協会　223-229　2013/07
強磁性トンネル接合を用いた高感度生体磁気センサの開発

西川卓男, 藤原耕輔, 大兼幹彦, 永沼博, 中里信和, 安藤康夫

応用物理学会秋季学術講演会講演予稿集(CD-ROM)　74th　2013

ISSN： 2758-4704
Nd₂Fe₁₄B系バルク単結晶の表面状態と磁化反転

小川大介, 齋藤龍真, 水野善幸, 小池邦博, 加藤宏朗, 宮崎孝道, 安藤康夫

日本磁気学会学術講演概要集　37th　2013

ISSN： 1882-2959
磁気抵抗素子センサーを用いた生体磁場計側

安藤康夫

工業材料　8　38-41　2013
Half-metallic Heusler alloys with low magnetic damping

OOGANE M, MIZUKAMI S, KUBOTA T, NAGANUMA H, ANDO Y

日本磁気学会研究会資料 = Bulletin of Topical Symposium of the Magnetics Society of Japan　183　21-24　2012/03/22
Publisher: 日本磁気学会
ISSN： 1882-2940
スピントロニクスとは何か

安藤康夫

OHM　99　(1)　17-20　2012
Publisher: オーム社
Pressure-induced half-metallic gap transformation in Co2MnSi observed by tunneling conductance spectroscopy

M. Nobori, Y. Sakuraba, Y. Miura, T. Nakano, J. Hasegawa, Y. Ohdaira, Y. Ando, K. Takanashi, G. Oomi

Physical Review B　83　(10)　104410　2011

DOI： 10.1103/PhysRevB.83.104410 　

ISSN： 1098-0121
Optically induced magnetization dynamics and variation of damping parameter in epitaxial Co2MnSi Heusler alloy films

Y. Liu, L. R. Shelford, V. V. Kruglyak, Y. Sakuraba, M. Oogane, R. J. Hicken, Y. Ando

Physical Review B　81　(9)　094402　2010

DOI： 10.1103/PhysRevB.81.094402 　

ISSN： 1098-0121
Evidence of Fermi level control in a half-metallic Heusler compound Co2MnSi by Al-doping: Comparison of measurements with first-principles calculations

Y. Sakuraba, Y. Kota, T. Kubota, M. Oogane, A. Sakuma, Y. Ando, K. Takanashi

Physical Review B　81　(14)　144422　2010

DOI： 10.1103/PhysRevB.81.144422 　

ISSN： 1098-0121
26aVD-7 Time-resolved magneto-optical effect in perpendicularly magnetized Pt/Co/Pt trilayer films

Mizukami S., Sajitha E. P., Watanabe D., Wu F., Oogane M., Naganuma H., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　64　(2)　360-360　2009/08/18
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Fe-Co-NiおよびCo基フルホイスラー合金薄膜における磁気緩和

水上成美, 大兼幹彦, 窪田嵩秀, 渡邉大輔, 永沼博, 安藤康夫, 宮崎照宣

日本磁気学会誌まぐね　4　(5)　229-235　2009/04
Spin dynamics in spin torque magnetization reversal

ANDO Y, AOKI T, TAMAGAWA T, WATANABE D, MIZUKAMI S, YAKATA S, TANIGUCHI T, IMAMURA H, NAGANUMA H, OOGANE M, INAMI N, MIYAZAKI T

Bulletin of Topical Symposium of the Magnetics Society of Japan　165　25-30　2009/03/13
Publisher: 日本磁気学会
ISSN： 1882-2940
27aTF-12 Optical detection of spin relaxation in films of magnetic metals

Mizukami S., Oogane M., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　64　(1)　431-431　2009/03/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Generation of Spin Current by Spin Pumping and Physics

Y. Ando, S. Mizukami, S. Yakata, T. Taniguchi, H. Imamura, M. Oogane, T. Miyazaki

Magnetics Jpn.　4　73-81　2009
ホイスラー合金Co2MnSiを用いた高感度磁気抵抗素子の開発

桜庭裕弥, 岩瀬拓, 常木澄人, 斉藤今朝美, 大兼幹彦, 安藤康夫, 佐久間昭正, 高梨弘毅

IEICE Technical Report　(MR2008)　32　2008/11

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Development of high-sensitive magnetoresistance devices using half-metallic Heusler alloy Co2MnSi
BiFeO₃-BiCoO₃固溶体薄膜の磁気特性および強誘電性

永沼博, 安井伸太郎, 西田謙, 飯島高志, 舟窪浩, 岡村総一郎, 安藤康夫

応用物理学会学術講演会講演予稿集　69th　(2)　2008
MPBを有するBiFcO₃-BiCoO₃エピタキシャル薄膜の磁性と強誘電性

永沼博, 安井伸太郎, 西田謙, 舟窪浩, 飯島高志, 安藤康夫, 岡村総一郎

日本磁気学会学術講演概要集　32nd　2008

ISSN： 1882-2959
Evidence of local moment formation in Co-based Heusler alloys

N. D. Telling, P. S. Keatley, G. van, der Laan, R. J. Hicken, E. Arenholz, Y. Sakuraba, M. Oogane, Y. Ando, K. Takanashi, T. Miyazaki

Physical Review B　78　(18)　184438　2008

DOI： 10.1103/PhysRevB.78.184438 　

ISSN： 1098-0121
Synthesis and Properties of Co-Pt Alloy-Silica Core-Shell Particles

Yoshio Kobayashi, Hidekazu Kakinuma, Daisuke Nagao, Yasuo Ando, Terunobu Miyazaki, Mikio Konno

Journal of Sol-Gel Science and Technology　47　(1)　16-22　2008

DOI： 10.1007/s10971-008-1740-1 　
Damping parameter of free layer material in MRAM measured by using ferromagnetic resonance

ANDO Y., OOGANE M., WATANABE D., WATANABE M., YILGIN R., YAKATA S., MIYAZAKI T.

153　7-14　2007/02/27

ISSN： 1340-7562
IETS法によるMgO-TMR膜のバリア構造観測

玉野井健, 大兼幹彦, 安藤康夫, 田中努, 上原裕二, 渦巻拓也

次世代磁気記録材料・システムへの挑戦　2007
MgOバリアTMR膜の電気伝導特性

玉野井健, 大兼幹彦, 安藤康夫, 田中努, 上原裕二, 渦巻拓也

日本応用磁気学会学術講演概要集　31st　2007

ISSN： 1340-8100
Synthesis of SiO₂-Coated Magnetite Nanoparticles and Immobilization of Proteins on Them

Yoshio Kobayashi, Mayumi Yoshida, Daisuke Nagao, Yasuo Ando, Terunobu Miyazaki, Mikio Konno

Ceramic Transactions　198　135-141　2007
Nearly ideal half-metallic spin-polarization in Co2MnSi based magnetic tunnel junctions

Y. Sakuraba, M. Hattori, M. Oogane, H. Kubota, Y. Ando, A. Sakuma, N. D. Telling, P. Keatley, G. van, der Laan, E. Arenholz, R. J. Hicken, T. Miyazaki

Journal of Magnetic Society of Japan　31　(4)　338-343　2007

DOI： 10.3379/jmsjmag.31.338 　

ISSN： 0285-0192 1880-4004
スピンエレクトロニクスが先導する高効率デバイス開発の未来―磁気抵抗比向上とＭｇＯ―

安藤康夫

マグネシア・ミュー，タテホ化学　2007
27pPSA-7 Frequency dependence of electrically detected ferromagnetic resonance for magnetic thin films

Mizukami S., Nagashima S., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　61　(1)　437-437　2006/03/04
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Interfacial structure and half-metallic ferromagnetism in Co2MnSi-based magnetic tunnel junctions

Physical review. B　74　(22)　224439-1-224439-7　2006
Publisher: American Physical Society
DOI： 10.1103/PhysRevB.74.224439 　

ISSN： 1098-0121
MRAMの研究開発動向

安藤康夫

2006

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講習会資料
24aXN-3 Spin injection in the superconductor and the magneto-resistance effect using ferromagnetic double tunneling junctions.

Daibo T., Oogane M., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　60　(1)　407-407　2005/03/04
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
24aXN-1 Inelastic electron tunneling spectroscopy in Fe/MgO/Fe magnetic tunnel junctions

Miyakoshi T, Ando Y, Oogane M, Miyazaki T, Kubota H, Fukushima A, Nagahama T, Yuasa S

Meeting abstracts of the Physical Society of Japan　60　(1-3)　407-407　2005/03/04
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
スピンダイナミクスとスピントロニクスデバイス

安藤康夫, 水上成美, 宮崎照宣

固体物理　45　35-43　2005
Tunnel Magnetoresistive Effect of Ferromagnetic Tunnel Junctions by Using Co_2MnAl Heusler Alloy

NAKATA J., OOGANE M., KUBOTA H., ANDO Y., KATO H., SAKUMA A., MIYAZAKI T.

28　395-395　2004/09/21
Fabrication of Co_2MnAl epitaxial films by using sputtering method

SAKURABA Y., NAKATA J., OOGANE M., KUBOTA H., ANDO Y., KATO H., SAKUMA A., MIYAZAKI T.

28　394-394　2004/09/21
Fast magnetization reversal measurement of TMR junctions

ANDO Y., NAKAMURA H., YU J. H., KUBOTA H., MIYAZAKI T.

28　214-214　2004/09/21
Reduction of switching fields of sub-micro sized MTJs with synthetic ferromagnetic free layers

LEE Young Min, KUBOTA Hitoshi, ANDO Yasuo, MIYAZAKI Terunobu

28　215-215　2004/09/21
Bias-voltage dependence of MTJs depending on the crystal structure of bottom ferromagnetic electrode

AHN S. J., KATO T., ANDO Y., KUBOTA H., MIYAZAKI T.

28　109-109　2004/09/21
FMR spectrum-linewidth and spin diffusion length in Cu/Ni_<80>Fe_<20>/N(N=Cu, Cu/Pt)

YAKATA S., ANDO Y., MIZUKAMI S., MIYAZAKI T.

28　125-125　2004/09/21
Fabrication and Estimation of Ferromagnetic Single-Electron Tunneling Devices by Utilizing Metallic Nano-wire as Hard Mask Stencil

NIIZEKI T., KUBOTA H., ANDO Y., MIYAZAKI T.

28　122-122　2004/09/21
Process for a fabricating sub-micron MTJs using focused ion beam

WATANABE D., KUBOTA H., ANDO Y., MIYAZAKI T.

28　121-121　2004/09/21
Spin Injection into the Superconductor by Ferromagnetic Double Tunneling Junctions

DAIBOU T., OOGANE M., ANDO Y., MIYAZAKI T.

28　123-123　2004/09/21
27pXJ-4 Spin pumping in firromagnet/nonmagnet junctions

Ando Y, Nakamura H, Yakata S, Mizukami S, Kubota H, Miyazaki T

Meeting abstracts of the Physical Society of Japan　59　(1)　464-464　2004/03/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Universal memory MRAM

Y. Ando

OYO BUTURI　73　390-393　2004
高密度磁気メモリ

安藤康夫, 手束展規, 大野裕三, 栗野浩之, 久保田均, 大野英男

電子材料　43　(1)　136-141　2004
Fabrication of coplanar guides for ultra fast magnetic switching measurement

HANADA A., NAKAMURA H., KUBOTA H., ANDO Y., MIYAZAKI T.

27　274-274　2003/09/01

ISSN： 1340-8100
Fabrication of Tiny Double Magnetic Tunnel Junctions Using Side-Edge Thin Film Deposition Technique

NIIZEKI T., KUBOTA H., ANDO Y., MIYAZAKI T.

27　272-272　2003/09/01

ISSN： 1340-8100
Dry etching of magnetic thin films using CO-NH_3 gas

KUBOTA H., UEDA K., ANDO Y., MIYAZAKI T.

27　270-270　2003/09/01

ISSN： 1340-8100
Magnetization dynamics of ferromagnetic thin film in multilayers

NAKAMURA H., MIZUKAMI S., ANDO Y., KUBOTA K., MIYAZAKI T.

27　275-275　2003/09/01

ISSN： 1340-8100
Ferromagnetic tunnel junctions by using Co_2MnAl Heusler alloy

NAKATA J., OOGANE M., KUBOTA H., ANDO Y., KATO H., MIYAZAKI T.

27　266-266　2003/09/01

ISSN： 1340-8100
Fabrication of small magnetic tunnel junctions using focused ion beam

WATANABE D., KUBOTA H., ANDO Y., MIYAZAKI T.

27　271-271　2003/09/01

ISSN： 1340-8100
Thermal stability of synthetic ferrimagnet free layer for MTJ

LEE Young Min, KUBOTA Hitoshi, ANDO Yasuo, MIYAZAKI Terunobu

27　277-277　2003/09/01

ISSN： 1340-8100
Spin dynamics investigated using tunneling current and Kerr effect

ANDO Y., NAKAMURA H., MIZUKAMI S., HANADA H., KUBOTA H., MIYAZAKI T.

27　158-159　2003/09/01

ISSN： 1340-8100
Fabrication dependence of Spin Polarization for Tunneling Electron

OOGANE M., DAIBOU T., KUBOTA H., ANDO Y., MIYAZAKI T.

27　434-434　2003/09/01

ISSN： 1340-8100
Bias-voltage dependence of MTJs epitaxially-grown on Al_2O_3(0001) substrates

AHN Sung-Jin, KUBOTA Hitoshi, ANDO Yasuo, MIYAZAKI Terunobu

27　429-429　2003/09/01

ISSN： 1340-8100
Tunnel magnetoresistance effect for ferromagneto// superconductor //ferromagmeto double tunnel junctions

DAIBOU T., OOGANE M., KUBOTA H., ANDO Y., MIYAZAKI T.

27　435-435　2003/09/01

ISSN： 1340-8100
Local transport properties of ferromagnetic tunnel junctions with epitaxial ferromagnetic bottom electrodes

KATO T., YU J. H., ANDO Y., KUBOTA H., MIYAZAKI T.

27　431-431　2003/09/01

ISSN： 1340-8100
Luminescence properties of organic EL devices with ferromagnetic cathode

SHIKOH E., ANDO Y., MIYAZAKI T.

27　62-62　2003/09/01

ISSN： 1340-8100
スピン物性の制御はどこまで可能になったか?

宮崎照宣, 安藤康夫

應用物理　72　(6)　773-774　2003/06/10

ISSN： 0369-8009
Hard mask fabrication for MRAM elements using FIB assisted selective CVD

H. Kubota, M. Hamada, Y. Ando, T. Miyazaki

J. Appl. Phys　2003
Spin Dynamics

T. Miyazaki, Y. Ando, S. Mizukami, H. Nakamura

Materials Integration　16　23-28　2003
Fabrication and evaluation of magnetic tunnel junctions in 100 nm scale

KUBOTA H., HAMADA M., ANDO Y., MIYAZAKI T.

126　27-34　2002/11/22

ISSN： 1340-7562
Magnetic tunnel junction using an epitaxial Ni_<80>Fe_<20> thin film grown on a a single crystal Si substrate

YU J. H., LEE H. M., HAYASHI M., OOGANE M., KUBOTA H., ANDO Y., MIYAZAKI T.

26　10-10　2002/09/01

ISSN： 1340-8100
Tunneling conductance property for Al/Al-oxide/Ferromagnet junction

OOGANE M., DAIBOU T., KUBOTA H., ANDO Y., MIYAZAKI T.

26　9-9　2002/09/01

ISSN： 1340-8100
Dynamic magnetization reversal process of TMR junction

NAKAMURA H., ANDO Y., KUBOTA K., MIYAZAKI T.

26　16-16　2002/09/01

ISSN： 1340-8100
Fabrication of Nanometer-Sized TMR Junction Using E-beam Lithography

NIIZEKI T., KUBOTA H., ANDO Y., MIYAZAKI T.

26　11-11　2002/09/01

ISSN： 1340-8100
Fabrication of ferromagnetic tunnel junctions with high thermal and dielectric stability

IURA S., KUBOTA H., ANDO Y., MIYAZAKI T.

26　14-14　2002/09/01

ISSN： 1340-8100
Analysis of the Insulator/Ferromagnet Interface and the Transport Properties in TMR Devices

ANDO Y., HAYASHI M., KUBOTA H., MIYAZAKI T.

26　8-8　2002/09/01

ISSN： 1340-8100
Fabrication of magnetic tunnel junctions using epitaxial NiFe (111) ferromagnetic bottom electrodes

H. Yu, M. Hayashi, M. Oogane, H. Kubota, Y. Ando, T. Miyazaki, H. M. Lee

Appl. Phys. Lett　2002
トンネル磁気抵抗効果とスピンエレクトロニクスの展開

宮崎照宣, 安藤康夫, 久保田均

固体物理　38　109-124　2002
Barrier structure and spin-dependent transport of ferromagnetic tunnel junctions

ANDO Y., HAYASHI M., KUBOTA H., MIYAZAKI T.

25　144a-144b　2001/09/01

ISSN： 1340-8100
Magnetism and electrical transport properties of metal chelate complex, Alq_3

SHIKOH E., ANDO Y., MIYAZAKI T.

25　190-190　2001/09/01

ISSN： 1340-8100
Ferromagnetic tunnel junctions prepared by several oxidation methods

IURA S., KUBOTA H., ANDO Y., MIYAZAKI T.

25　337-337　2001/09/01

ISSN： 1340-8100
Properties of ferromagnetic tunnel junctions with extremely thin Al-oxide using plasma oxidation

YAOITA K., KUBOTA H., ANDO Y., MIYAZAKI T.

25　338-338　2001/09/01

ISSN： 1340-8100
Magnetoresistance mesurement for ultra small TMR junctions using conductive AFM

KUBOTA H., ANDO Y., MIYAZAKI T., REISS G., BRUCKL H., SCHEPPER W., WECKER J., GIERES G.

25　341-341　2001/09/01

ISSN： 1340-8100
Measurement of spin polarization using tunneling spectroscopy

OOGANE M., KUBOTA H., ANDO Y., MIYAZAKI T.

25　336-336　2001/09/01

ISSN： 1340-8100
Tunnel magnetoresistance effect for double junctions with superconductor middle layer

DAIBOU T., OOGANE M., KUBOTA H., ANDO Y., MIYAZAKI T.

25　344-344　2001/09/01

ISSN： 1340-8100
Oxidation Process of Insulator Layer in Ferromagnetic Tunnel Junction

HAYASHI M., ANDO Y., OOGANE M., KUBOTA H., MIYAZAKI T.

25　339-339　2001/09/01

ISSN： 1340-8100
Tunnel Magnetoresistance Effect for Double Tunnel Junctions with Superconducting Intermediate Layer

Daibou T., Oogane M., Ando Y., Kim C., Song O., Miyazaki T

Meeting abstracts of the Physical Society of Japan　56　(1)　711-711　2001/03/09
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
スピンが担うエレクトロニクスの未来

安藤康夫

パリティ　16-12　23-29　2001
強磁性トンネル接合の絶縁障壁と高速スイッチング特性

安藤康夫, 林将光, 中村洋明, 井浦聡則, 水上成美, 久保田均, 宮崎照宣

日本応用磁気学会第121回研究会資料　11-18　2001
Magnetic and optical properties for organic-inorganic layered perovskites

SHIKOH E., ANDO Y., ERA M., MIYAZAKI T.

24　188-188　2000/09/01

ISSN： 1340-8100
The Magnetic Relaxation for Ni_<80>Fe_<20> Thin Film

MIZUKAMI S., ANDO Y., MIYAZAKI T.

24　183-183　2000/09/01

ISSN： 1340-8100
Spin dependent local transport properties of ferromagnetic tunnel junctions

HAYASHI M., ANDO Y., KUBOTA H., MIYAZAKI T.

24　45-45　2000/09/01

ISSN： 1340-8100
IET Spectra of ferromagnetic tunnel junctions fabricated by different oxidization conditions

MURAI J., ANDO Y., DAIBOU T., YAOITA K., MIYAZAKI T.

24　39-39　2000/09/01

ISSN： 1340-8100
Fabrication of low resistance ferromagnetic tunnel junctions using plasma oxidation

YAOITA K., KAMIJO M., NIIZEKI T., YAMAMOTO T., KUBOTA H., ANDO Y., MIYAZAKI T.

24　47-47　2000/09/01

ISSN： 1340-8100
Fabrication and magnetoelectric properties of high-magnetoresistance tunnel junctions

HAN X. F., DAIBOU T., YAOITA K., ANDO Y., KUBOTA H., MIYAZAKI T.

24　46-46　2000/09/01

ISSN： 1340-8100
Tunnel magnetoresistance effect for double junctions with Al middle layer

DAIBOU T., OOGANE M., ANDO Y., KIM Changkyung, SONG Ohsung, MIYAZAKI T.

24　52-52　2000/09/01

ISSN： 1340-8100
Transport properties in ferromagnetic double barrier junctions

SIRIPONGSAKUL T., OOGANE M., MURAI J., YU Andrew C. C., KUBOTA H., ANDO Y., MIYAZAKI T., KIM Changkyung, SONG Ohsung

24　51-51　2000/09/01

ISSN： 1340-8100
Annealing effects of magnon-induced inelastic excitation of ferromagnetic tunnel junctions

Murai J., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　55　(1)　361-361　2000/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Measurement of Spin Polarization for Fe,Co,Ni using Tunneling Spectroscopy

Oogane M., Tezuka N., Kubota H., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　55　(1)　410-410　2000/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
The Study on Ferromagnetic Resonance Linewidth for (80NiFe)_<1-x>Pt_x thin films

Mizukami S., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　55　(1)　402-402　2000/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Magnon Excitation at the Interface of Co/Al/Al-Oxide/Co Tunnel Junctions

MURAI J., ANDO Y., KAMIJO M., DAIBOU T., KUBOTA H., MIYAZAKI T., KIM Changkyung, SONG Ohsung

Journal of the Magnetics Society of Japan　24　(4-2)　615-618　2000
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.24.615 　

ISSN： 0285-0192

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Inelastic-electron-tunneling spectroscopy (IETS) was used to investigate the electron states of the Co/Al(d_Al)/Al-oxide/Co interface in ferromagnetic tunnel junctions. The IET spectra for both parallel and anti-parallel magnetization configurations of ferromagnetic electrodes showed a strong positive peak for d_Al = 0 Å. The subtraction spectrum defined by the difference between the spectra of the two configurations was calculated. The subtraction spectrum indicates only a magnon-assisted inelastic tunneling process. The tendency of the tunneling magnetoresistance (TMR) ratio to decrease with bias voltage agreed with the shape of the subtraction spectrum. By assuming surface magnon inelastic excitation, we obtained the distributions of correlation length and Curie temperature for both ferromagnetic electrode surfaces on the insulator. If an Al layer was inserted between a ferromagnet and an insulator, the subtraction spectrum showed an asymmetry to the bias voltage and magnon inelastic excitation at the interface decreased.
Magnetism and the optical properties of the organic ammonium-3d transition metal salts

SHIKOH E., ANDO Y., ERA M., MIYAZAKI T.

23　312-312　1999/10/01
Magnon-induced inelastic excitation of spin-valve type tunnel junction

MURAI J., ANDO Y., KAMIJO M., KUBOTA H., MIYAZAKI T.

23　425-425　1999/10/01
Buffer-layer dependence of ferromagnetic resonance linewdth for Ni_<80>Fe_<20> thim films

MIZUKAMI S., ANDO Y., MIYAZAKI T.

23　379-379　1999/10/01
TMR and Coulomb blockade in the tunnel junction with Co nano-particles

KUBOTA H., FUKUMOTO Y., THAMRONGSING S., ANDO Y., MIYAZAKI T.

23　284-284　1999/10/01
Local transport properties of Al-oxide of ferromagnetic tunnel junctions

ANDO Y., KAMEDA H., KUBOTA H., MIYAZAKI T.

23　275-275　1999/10/01
Tunnel magnetoresistance effect for Ni_<80>Fe_<20>Co/N(N=Ta, Al)/Al-oxide/Co junctions

DAIBOU T., TEZUKA N., KUBOTA H., ANDO Y., MIYAZAKI T.

23　273-273　1999/10/01
Magnetoresistance effect in ferromagnetic tunnel junctions with ultra thin Al-O films

KAMIJO M., KUBOTA H., ANDO Y., MIYAZAKI T.

23　271-271　1999/10/01
The dependence of TMR on plasma oxidation time and Al thickness in Ni-Fe/Co/Al-O/Co junctions

KUBOTA H., OTSUKA S., KAMIJO M., YU C. C., TEZUKA N., ANDO Y., MIYAZAKI T.

23　272-272　1999/10/01
26pPSA-49 TMR and Coulomb blockade in Co/Co-AlO_x/Co junctions

Kubota H, Siripongsakul T, Fukumoto Y, Ando Y, Miyazaki T

Meeting abstracts of the Physical Society of Japan　54　(2)　420-420　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
26pPSA-46 Tunnel magnetoreisistance effect for Ni_<80>Fe_<20>/Co/N/N-oxide/Co(N=Ta, Al)junctions

Daibou T, Tezuka N, Kubota H, Ando Y, Miyazaki T

Meeting abstracts of the Physical Society of Japan　54　(2)　420-420　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
26pPSA-45 Spin Polarization Measurement using Tunneling Spectroscopy

Oogane M, Tezuka N, Kubota H, Ando Y, Miyazaki T

Meeting abstracts of the Physical Society of Japan　54　(2)　419-419　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
26pPSA-47 Inelastic-Electron-Tunneling-Spectra of Ni_<80>Fe_<20>/Co/Al(d_<Al>)/Al-oxide/Co junctions

Murai J, Ando Y, Daibou T, Miyazaki T

Meeting abstracts of the Physical Society of Japan　54　(2)　420-420　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
26aYQ-7 Influence of nonmagnetic layer(NM) on FMR linewidth for NM/80NiFe/NM thin films

Mizukami S, Ando Y, Miyazaki T

Meeting abstracts of the Physical Society of Japan　54　(2)　397-397　1999/09/03
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
29a-J-3 FMR linewidth for 80NiFe and Co ultrathin films

Mizukami S., Ando Y., Miyazaki T.

Meeting abstracts of the Physical Society of Japan　54　(1)　420-420　1999/03/15
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Synthesis and the magnetism of the naphtylamin-3d transition metal salts

ANDO Y., SHIKOH E., MIYAZAKI T.

22　257-257　1998/09/01
Thickness dependence of ferromagnetic resonance for Co and 80NiFe thin films

MIZUKAMI S., ANDO Y., MIYAZAKI T.

22　261-261　1998/09/01
Magnetoresistivee effect in ferromagnetic tunneling junctions with wedge shaped insulator

ANDO Y., YOKOTA M., MIYAZAKI T.

22　453-453　1998/09/01
Inelastic-Electron-Tunneling-Spectra of Al/Al_2O_3/Co/Al junctions

MURAI J., ANDO Y., MIYAZAKI T.

Meeting abstracts of the Physical Society of Japan　53　(1)　427-427　1998/03/10
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
高分子化合物を用いた機能性ＬＢ膜組織体の形成

宮下徳治, 安藤康夫, 宮崎照宣

日本油学会誌　47　(4)　323-331　1998
Publisher: Japan Oil Chemists' Society
DOI： 10.5650/jos1996.47.323 　

ISSN： 1341-8327

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LB films composed of polymer compounds are of interest as potential sources of new materials. Various factors influencing the formation of stable polymer monolayer are reviewed from a difference from low molecular weight monolayers. As a new type of polymer LB films, fluorinated polymer LB films with excellent surface properties such as water repellency and lubricant, and polymer LB films containing organic magnetic functionality are discussed.
Synthesis and the magnetism of the amin-3d transition metal salts

ANDO Y., SHIKOH E., MIYAZAKI T.

21　79-79　1997/10/01
Analysis of the interlayer in ferromagnet/insulator junction by inelastic-electron-tunneling-spectroscopy.

MURAI J., ANDO Y., TEZUKA N., MIYAZAKI T.

21　174-174　1997/10/01
Magnetoresistance effect in ferromagnetic tunneling junctions with wedge shaped insulator

YOKOTA M., ANDO Y., TEZUKA N., MIYAZAKI T.

21　173-173　1997/10/01
Polarized electron spin conduction in ferromagnet-dye junction

ANDO Y., MURAI J., MIYAZAKI T.

20　137-137　1996/09/01
Relationship between the barrier and magnetoresistance effect in ferromagnetic tunneling junctions

TEZUKA N., ANDO Y., MIYAZAKI T., TOMPKINS H. G., TEHRANI S. T., GORONKIN H. G.

20　136-136　1996/09/01
Ferromagnetic Resonance in 70CoNi/Cu/80NiFe trilayer

MIZUKAMI S., ANDO Y., MIYAZAKI T.

20　54-54　1996/09/01
Ferromagnetic resonance in 80Ni-Fe/Cu/Co/Cu80Ni-Fe superlattices

ANDO Y., KOIZUMI H., MIYAZAKI T.

19　343-343　1995/09/01
High field magnetization in pseudo-binary R-Fe(R=Pr, Nd, Sm, Tb, Dy, Er) amorphous alloys

Kurita N., Kato H., Ando Y., Miyazaki T.

Abstracts of the meeting of the Physical Society of Japan. Annual meeting　50　(3)　41-41　1995/03/16
Publisher: The Physical Society of Japan (JPS)
3a-YA-12 Magnetic phase diagram for R-Fe pseudo-dinary amorphous alloys with random magnetic anisotropy

Kurita N, Kato H, Ando Y, Ishio S, Miyazaki T

Abstracts of the meeting of the Physical Society of Japan. Sectional meeting　1994　(3)　67-67　1994/08/16
Publisher: The Physical Society of Japan (JPS)
3p-YA-7 Magnetic tunneling effect in ferromagnet/Al-Al_2O_3/ferromagnet junction

Tezuka N, Ando Y, Miyazaki T

Abstracts of the meeting of the Physical Society of Japan. Sectional meeting　1994　(3)　84-84　1994/08/16
Publisher: The Physical Society of Japan (JPS)
1a-S-4 Study on 80Ni-Fe/Cu Multilayer Films

Koizumi H., Sato M., Ando Y., Ishio S., Miyazaki T.

Abstracts of the meeting of the Physical Society of Japan. Annual meeting　48　(3)　142-142　1993/03/16
Publisher: The Physical Society of Japan (JPS)
31p-PS-15 Fe-Ni-Mn合金のリエントラントスピングラス(磁性(磁性理論及びスピングラス))

宮崎照宣, 安藤康夫, 高橋実

年会講演予稿集　41　(3)　137-137　1986/03/29
Publisher: 一般社団法人日本物理学会
3a-PS-9 Fe_<65>(Ni_<1-x>Mn_x)_<35>(0≦x≦0.3)合金のスピングラス

宮崎照宣, 安藤康夫, 高橋実

秋の分科会講演予稿集　1985　(3)　119-119　1985/09/13
Publisher: 一般社団法人日本物理学会
31a-D3-10 Fe_<65>Ni_<35>インバー合金のリエントラントスピングラス(磁性(スピングラス))

高橋実, 安藤康夫, 宮崎照宜

年会講演予稿集　40　(3)　69-69　1985/03/31
Publisher: 一般社団法人日本物理学会
12a-T-4 Fe-Niインバー合金のスピングラス

高橋実, 岡本巌, 安藤康夫, 宮崎照宣

秋の分科会講演予稿集　1983　(3)　88-88　1983/09/13
Publisher: 一般社団法人日本物理学会

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Books and Other Publications 8

8) 生体情報センシングとヘルスケアへの最新応用

ANDO Yasuo

技術情報協会　2017/06
新しい磁気センサとその応用

安藤康夫

(株)トリケップス　2013
技術シーズを活用した研究開発テーマの発掘

安藤康夫

技術情報協会　2013
スピンポンピングと磁化ダイナミクス

安藤康夫

シーエムシー出版　2009
Optically stimulated magnetization dynamics of epitaxial Heusler alloy films

Y. Liu, L. R. Shelford, V. V. Kruglyak, R. J. Hicken, Y. Sakuraba, M. Oogane, Y.Ando, T. Miyazaki

Research Signpost　2009
磁気抵抗効果再生磁気ヘッドの基本原理

安藤康夫

シーエムシー出版　2007
トンネル磁気抵抗材料

安藤康夫

株式会社フジ・テクノシステム　2005
Spin dynamics

Y. Ando, S. Mizukami, H. Nakamura, H. Kubota, T. Miyazaki

シーエムシー出版　2004/12

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Presentations 86

超高感度磁気センサの可能性 Invited

安藤康夫

第33回東北地域の車を考える会　2018/09/21
Recent progress of biomagnetic field sensors with ferromagetic tunnel junctions Invited

安藤康夫

第42回日本磁気学会講演会　2018/09/12
Recent Progress of Bio-magnetic Field Sensors with Ferromagnetic Tunnel Junctions (MTJs) International-presentation Invited

ANDO Yasuo

Annual World Congress of Smart Materials 2018 “Weaving an Avatar Dream Together”　2018/04/07
Recent progress of bio-magnetic field sensors with ferromagnetic tunnel junctions (MTJs) International-presentation Invited

ANDO Yasuo

Tohoku/SG-Spin Workshop on Spintronics　2018/02/21
トンネル磁気抵抗素子を用いた生体磁場測定装置の開発と展望 Invited

安藤康夫

日本学術振興会「先端ナノデバイス・材料テクノロジー」151委員会平成29年度第5回研究会　2018/01/24
トンネル磁気抵抗素子を用いた生体磁場測定装置の開発 Invited

安藤康夫

東北大学レアメタル・グリーンイノベーション研究開発センター第３回フォーラム～クリーンエネルギー関連デバイス部門研究成果～　2017/12/22
TMRを用いた生体磁気センサの開発「社会基盤の向上につながる磁気センサとその活用」 Invited

安藤康夫

第5回岩崎コンファレンス　2017/11/27
Bio-magnetic field sensor application of magnetic tunnel junctions International-presentation Invited

ANDO Yasuo

2017 Lorraine-Mainz-Tohoku Joint Seminar　2017/11/03
Magnetic field sensor application of magnetic tunnel junctions International-presentation Invited

ANDO Yasuo

SSDM 2017　2017/09/21
Development of Spintronics and Device Application International-presentation Invited

ANDO Yasuo

The 2017 International Meeting for Future of Electron Devices　2017/06/29
Development of bio-magnetic sensors operating at room temperature with ferromagnetic tunnel junctions International-presentation Invited

ANDO Yasuo

Biomagnetic Sendai 2017　2017/05/23
トンネル磁気抵抗磁場センサの開発と生体磁場計測への応用 Invited

安藤康夫

第64回応用物理学会春季学術講演会　2017/03/16
Bio-magnetic field sensor application of magnetic tunnel junctions International-presentation Invited

ANDO Yasuo

4th JSPS Core-to-Core Workshop on “New concept Spintronic Devices”　2016/11/20
Development of bio-magnetic field measurement system with tunnel magnetoresistance devices International-presentation Invited

ANDO Yasuo

2016 DISKCON JAPAN　2016/05/26
ホイスラー合金を用いた強磁性トンネル接合のデバイス応用の展望 Invited

安藤康夫

日本金属学会 2015年秋季講演大会　2015/09/17
“強磁性トンネル接合を用いた高感度磁場センサの開発と展望” Invited

日本磁気学会第203回研究会　2015/07/24
“高感度TMRを用いた生体磁場測定デバイス” Invited

日本学術振興会薄膜第131委員会、半導体界面制御技術第154委員会合同研究会　2015/02/24
“高感度TMRを用いた生体磁場測定デバイス” Invited

JR東海第25回技術開発部セミナー　2014/11/11
”Bio-magnetic field sensor application of magnetic tunnel junctions” International-presentation Invited

The 6th IEEE international Nanoelectronics Conference 2014 (IEEE INEC 2014)　2014/07/29
“強磁性トンネル接合を用いた高感度磁気センサの応用と展望” Invited

日本磁気学会第197回研究会「高感度磁気センサの研究と製品」　2014/07/11
”強磁性トンネル接合を用いた生体磁気計測の現状と進歩” Invited

第53回日本生体医工学会オーガナイズドセッション「生体磁気計測技術の進歩」　2014/06/24
”Bio-magnetic field sensor application of magnetic tunnel junctions” International-presentation Invited

Yasuo Ando, Daiki Kato, Kosuke Fujiwara, Hiroshi Naganuma, Mikihiko Oogane, T. Nishikawa

The AIMR International Symposium 2014 (AMIS 2014) “Toward emergence of new materials science with mathematics collaboration”　2014/02/18
“Magnetic materials with high thermal stability and low magnetic damping” International-presentation Invited

The 2nd SRJ MRAM Forum 2013　2013/11/20
“MTJ-based Spintronics” International-presentation Invited

SSDM2013 SHORT COURSE B. “Fundamentals and Applications of Spintronics Frontier”　2013/09/24
“強磁性トンネル接合を用いた生体磁気計測の現状と展望” Invited

第28回日本生体磁気学会　2013/06/07
“トンネル磁気抵抗素子を用いた心磁場および脳磁場の計測” Invited

安藤康夫, 藤原耕輔, 大兼幹彦, 永沼博, 西川卓男

日本磁気学会第44回スピンエレクトロニクス専門研究会　2013/03/06
“スピンによる生体磁場計測－革新的スピントロニクス医療デバイスの創成の可能性－” Invited

安藤康夫, 西川卓男

平成24年度東北地区高等専門学校専攻科産学連携シンポジウム　2013/03/02
“XMCDを用いた強磁性トンネル接合界面の解析と伝導特性” Invited

第二回東北大学光・量子ビーム科学連携ワークショップ　2013/01/08
スピンによる心磁図・脳磁図計測－革新的スピントロニクス医療デバイスの創成の可能性 Invited

第7回 ATI合同研究会『スピンと生命の融合』—バイオスピントロニクスの可能性を探る　2012/11/27
“Large magnetoresistance effect in Epitaxial Co2FexMn1-xSi/Ag/ Co2FexMn1-xSi Devices” Invited

Jo Sato, Mikihiko Oogane, Hiroshi Naganuma, Yasuo Ando

第73回応用物理学会学術講演会応用物理学会優秀論文賞受賞記念講演　2012/09/13
“スピントロニクス技術による生体磁場センサ” Invited

安藤康夫, 藤原耕輔, 大兼幹彦, 永沼博, 西川卓男

第73回応用物理学会学術講演会　2012/09/12
Advanced spintronic materials and transport phenomena International-presentation Invited

Japan-Germany Progress Seminar “Spin and Quantum Information”　2011/11/24
スピントロニクスの現状と今後の展開 Invited

デンソー共同研究講演会　2011/11/04
二重強磁性トンネル接合の磁気抵抗効果 Invited

第71回応用物理学会学術講演会　2011/09/14
Progress of magnetoresistance effect in MTJs with Heusler alloys International-presentation Invited

2nd Meeting of Strategic Japanese-German Joint Research Program“ASPIMATT” : Advanced spintronic materials and transport phenomena　2010/10/19
強磁性トンネル接合を用いた極微小磁界検出の可能性 Invited

コニカミノルタオプト講演会　2010/10/01
二重強磁性トンネル接合の磁気抵抗効果 Invited

第34回日本磁気学会学術講演会　2010/09/04
二重障壁強磁性トンネル素子およびホイスラー合金を用いた素子における磁気抵抗効果 Invited

International Disk Forum 国際ディスクフォーラム2010 (DISKCON)　2010/07/30
MgO二重障壁強磁性トンネル接合における巨大磁気抵抗効果 Invited

Lixian Jiang, 永沼博, 大兼幹彦

春季第 57回応用物理学関係連合講演会　2010/03/18
MgO障壁層を用いた二重強磁性トンネル接合における巨大磁気抵抗効果 Invited

IDEMA JAPAN 合同部会講演会　2009/12/04
MgO障壁層を用いた二重強磁性トンネル接合における磁気抵抗効果 Invited

第４回スピントロニクス技術分科会　2009/11/12
ホイスラー合金を用いた強磁性トンネル接合の磁気抵抗効果と界面制御 Invited

応用物理学会シリコンテクノロジー分科会　2009/03/16
スピントルク磁化反転におけるスピンダイナミクス Invited

安藤康夫, 青木達也, 玉川聖, 渡邉大輔, 水上成美, 家形諭, 谷口知大, 今村裕志, 永沼博, 大兼幹彦, 宮崎照宣

日本磁気学会第165回研究会　2009/03/13
Perspective of High Tunnel Magnetoresistance in Magnetic Tunnel Junctions with Heusler Alloy Electrodes and MgO Barrier International-presentation Invited

Y. Ando, S. Tsunegi, T. Kubota, G. Kim, T. Hiratsuka, Y. Sakuraba, M. Oogane, K. Takanashi, S. Mizukami, T. Miyazaki

Tohoku-York Research Seminar　2009/01/20
強磁性トンネル接合における磁気抵抗効果と界面制御 Invited

第１回界面科学研究会，表面・界面制御による新物質層の探索　2008/12/19
新潟高校特別授業 Invited

安藤康夫

最先端技術と産業を支える工学研究～磁石で考えるナノテクノロジー　2008/03/24
スピンエレクトロニクス技術の現状と将来展望 Invited

富士電機デバイステクノロジー株式会社技術講演会　2007/10/10
MRAMの研究開発動向 Invited

次世代不揮発メモリのデバイス原理と研究開発動向　2007/04/26
Preparation of magnetic tunnel junctions with ferromagnetic electrodes of high spin polarization International-presentation Invited

FG559 meeting, Mainz, Germany　2007/04/16
強磁性共鳴を用いたMRAMフリー層材料の磁気緩和定数測定 Invited

大兼幹彦, 渡邉大輔, 渡邉美穂, Resul Yilgin, 家形諭, 宮崎照宣

日本応用磁気学会第153回研究会，第15回スピンエレクトロニクス専門研究会　2007/02/27
High spin-polarized state observed in magnetic tunnel junctions with Co2MnSi electrodes International-presentation Invited

Y. Ando, Y. Sakuraba, M. Oogane, A. Sakuma, T. Miyazaki

Japan-Germany Joint Workshop 2006, “Nano-Electronics”　2006/11/30
マイクロ波とスピンダイナミクス Invited

東北大学電気通信研究所共同プロジェクト研究会　2006/09/28
Recent progress in tunnel magnetoresistance effect and the application to spintronics devices International-presentation Invited

Y. Ando

KINKEN-WAKATE　2006/08/26
ナノテクノロジーと私たちの生活～究極の微小磁石-スピン-を利用したナノテク～ Invited

佐沼高校　2006/08/01
強磁性トンネル接合における巨大磁気抵抗効果の進展と磁気メモリへの応用 Invited

安藤康夫, 大兼幹彦, 宮崎照宣

東北大学多元研研究会　2006/06/03
Spin-dependent spectroscopy of MTJs with high spin polarization materials International-presentation Invited

Y. Ando, T. Miyakoshi, T. Daibou, M. Oogane, T. Miyazaki, S. Yuasa

3rd Int. Symposium “Thin Films of Heusler Compounds, a Challenge　2005/11/12
Large magnetoresistance in MTJs with full-Heusler alloy electrode International-presentation Invited

Y. Ando, Y. Sakuraba, M. Oogane, H. Kubota, T. Miyazaki

3rd Int. Symposium Thin Films of Heusler Compounds, a Challenge　2005/11/11
Recent progress in magnetic tunnel junctions with MgO barrier International-presentation Invited

Y. Ando, M Oogane, T. Daibou, T. Miyakoshi, S. Yuasa, T. Miyazaki

Johannes Gutenberg-Universität seminar　2005/06/24
Recent development of MRAM (magnetic random access memory) and related phenomena International-presentation Invited

Y. Ando, M. Oogane, Y. Sakuraba, Y.M. Yi, J. Nakata, R. Yilgin, H. Kubota, T. Miyazaki

Physikalisches Kolloquium, Fachbereich Physik　2005/05/02
Large magnetoresistance in magnetic tunnel junctions using Co-Mn-Al full Heusler alloy International-presentation Invited

Y. Ando, M. Oogane, Y. Sakuraba, J. Nakata, R. Yilgin, H. Kubota, T. Miyazaki

Johannes Gutenberg-Universität seminar　2005/03/18
スピン緩和とスピンデバイスへの展開 Invited

安藤康夫, 水上成美, 中村洋明, 家形諭, 大坊忠臣, 宮崎照宣

日本応用磁気学会第8回ナノマグネティックス専門研究会　2004/10/22
強磁性体/非磁性体接合におけるスピンポンピングとスピン拡散長 Invited

安藤康夫, 家形諭, 中村洋明, 水上成美, 宮崎照宣

日本金属学会 2004年秋期大会シンポジウム　2004/09/29
強磁性体/非磁性体接合におけるスピンポンピング Invited

安藤康夫, 家形諭, 水上成美, 中村洋明, 久保田均, 宮崎照宣

日本物理学会第59回年次大会シンポジウム　2004/03/27
メタル系スピントロニクスデバイスとダイナミクス Invited

安藤康夫, 水上成美, 中村洋明, 家形諭, 久保田均, 宮崎照宣

文部科学省科学研究費補助金特定領域研究「半導体ナノスピントロニクス」平成15年度報告会　2004/01/27
TMR素子の分極率とトンネル分光 Invited

NHK技術研究会　2004/01/08
Effect of spin pumping on Gilbert damping for thin permalloy films detected by using time-resolved Kerr effect International-presentation Invited

Y. Ando, S. Mizukami, H. Nakamura, H. Kubota, T. Miyazaki

International Symposium on Magnetic Materials and Application　2003/12/04
Magnetic tunnel junctions with epitaxially-grown bottom electrodes International-presentation Invited

Y. Ando, J.H. Yu, S.J. Ahn, T. Kato, M. Oogane, H. Kubota, T. Miyazaki

International workshop on Nano-scale Magnetoelectronics　2003/11/25
コンタクトAFM同時電流測定による強磁性トンネル接合絶縁層の局所評価 Invited

JEOL仙台表面分析懇話会　2003/11/06
TMR素子の基礎と物性 Invited

NHK技術研究会　2003/10/06
スピンダイナミクスの電気的および光学的アプローチ Invited

安藤康夫, 中村洋明, 水上成美, 花田成, 久保田均, 宮崎照宣

第27回応用磁気学会学術講演会シンポジウム　2003/09/17
Interface Characterization of Magnetic Tunnel Junctions International-presentation Invited

Y. Ando, H. Kubota, T. Miyazaki

KIST seminar　2002/10/29
MRAMに関わるTMR素子の絶縁特性とスピン反転 Invited

安藤康夫, 林将光, 中村洋明, 久保田均, 宮崎照宣

第49回応用物理学関係連合講演会シンポジウム　2002/03/29
Growth Mechanism of Thin Insulating Layer in Ferromagnetic Tunnel Junctions Prepared by Various Oxidation Methods International-presentation Invited

Y. Ando, M. Hayashi, S. Iura, K. Yaoita, H. Kubota, T. Miyazakiubota, T. Miyazaki

17th International Colloquium on Magnetic Films and Surfaces　2002/03/04
強磁性トンネル接合における絶縁層/強磁性層界面状態と耐熱特性 Invited

安藤康夫, 林将光, 久保田均, 宮崎照宣

金研ワークショップ「遷移金属酸化物薄膜における新機能創製の研究」　2001/11/25
強磁性トンネル接合の絶縁障壁と高速スイッチング特性 Invited

安藤康夫, 林将光, 中村洋明, 井浦聡則, 水上成美, 久保田均, 宮崎照宣

応用磁気学会研究会「スピンエレクトロニクスの現状と将来展望」　2001/10/23
強磁性トンネル接合の絶縁障壁とスピン依存伝導 Invited

安藤康夫, 林将光, 久保田均, 宮崎照宣

第25回日本応用磁気学会学術講演会シンポジウム　2001/09/26
強磁性トンネル接合の絶縁障壁とスピン依存伝導 Invited

安藤康夫, 林将光, 久保田均, 宮崎照宣

第45回日本学術会議材料研究連合講演会　2001/09/18
テラビット開発に向けたTMR素子の要件と課題 Invited

情報ストレージ技術専門委員会　2001/07/31
Growth Mechanism of Thin Insulating Layer in Ferromagnetic Tunnel Junctions Analyzed by Conducting AFM Method International-presentation Invited

Y. Ando, M. Hayashi, K. Yaoita, S. Iura

International Symposium on Physics of Magnetic Materials　2001/05/13
TMR素子の局所伝導特性と磁気抵抗効果 Invited

第40回磁性多層膜の新しい機能専門研究会　2001/01/21
Recent Development for Ferromagnetic Tunnel Junctions International-presentation Invited

2nd Workshop for 21C Frontier Project　2000/11/02
Spin Dependent Tunneling in Ferromagnet/Insulator/Ferromagnet Junctions with poly-N dodecyl-acrylamide LB Film International-presentation Invited

Nano-molecular Electronics '97　1997/12/10
高分子フェロセン誘導体LB膜の構造と磁性 Invited

第46回高分子討論会　1997/10/02
金属人工格子における磁性層間相互作用とスピントランスポート Invited

安藤康夫, 手束展規, 水上成美, 古泉浩, 宮崎照宣

東大COE研究会　1996/03
Langmuir-Blodgett法による有機分子強磁性体薄膜の作製 Invited

秋田大学薄膜研究会「磁性薄膜の基礎・応用研究の進展」　1995/11/17
高分子LB膜を用いた80NiFe/PDDA/Co接合の磁気トンネリング効果 Invited

安藤康夫, 廣池太郎, 宮崎照宣

磁性多層膜の新しい機能専門研究会　1995/07/18

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Industrial Property Rights 69

Mn系強磁性薄膜の製造方法およびMn系強磁性薄膜

大兼幹彦, 安藤康夫, 渡部健太

Property Type: Patent
磁気センサおよびその製造方法

古市喬干, 青建一, 阿部竜一郎, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
磁気抵抗素子、磁気検出装置、及び磁気抵抗素子の製造方法

古市喬干, 青建一, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
磁気センサ

古市喬干, 青建一, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
トンネル磁気抵抗素子及びその製造方法

安藤康夫, 大兼幹彦, 藤原耕輔, 城野純一, 土田匡章

Property Type: Patent
トンネル磁気抵抗素子及びその製造方法

安藤康夫, 大兼幹彦, 藤原耕輔, 城野純一

Property Type: Patent
磁気センサー、センサーユニット、磁気検出装置、及び磁気計測装置

藤原耕輔, 大兼幹彦, 安藤康夫, 城野純一, 寺内孝

Property Type: Patent
Mn系強磁性薄膜およびその製造方法、ならびにMn系強磁性薄膜を有する磁気トンネル接合素子

大兼幹彦, 安藤康夫, 栗本雄太, 渡部健太, 窪田美穂

Property Type: Patent

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【優先権主張番号】特願2015-210894，【優先日】平成27年10月27日
磁気センサ

矢野敏史, 青建一, 安藤康夫, 大兼幹彦

Property Type: Patent
マルチフェロイック素子

永沼博, 一ノ瀬智浩, 大兼幹彦, 安藤康夫

Property Type: Patent
磁気抵抗素子

矢野敏史, 青建一, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
磁気センサ

矢野敏史, 青建一, 古市喬干, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
磁気抵抗素子およびそれを用いた磁気センサ

矢野敏史, 青建一, 安藤康夫, 大兼幹彦, 中野貴文

Property Type: Patent
磁気センサー及びその製造方法

西川卓男, 安藤康夫

Property Type: Patent

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【優先権主張番号】特願2013-150339，【優先日】平成25年7月19日
マルチフェロイック薄膜及びそれを用いたデバイス

永沼博, フスネアラベガン, 窪田美穂, 佐藤敬, 大兼幹彦, 安藤康夫

Property Type: Patent
磁気抵抗素子及びそれを用いた磁気メモリ

永沼博, モハメドナズルル, イスラムカーン, 井波暢人, 大兼幹彦, 安藤康夫

Property Type: Patent
生体磁気センサー及びその製造方法

西川卓男, 荒川裕明, 安藤康夫, 大兼幹彦, 藤原耕輔

Property Type: Patent
磁気抵抗効果素子および磁気デバイス

大兼幹彦, 永沼博, 安藤康夫, 佐藤丈

Property Type: Patent
スピントランジスタおよび磁気デバイス

大兼幹彦, 永沼博, 安藤康夫, 大平祐介

Property Type: Patent
生体磁気計測装置、生体磁気計測システム、及び、生体磁気計測方法

西川卓男, 安藤康夫

Property Type: Patent

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【優先権主張番号】特願2010-202540，【優先日】平成22年9月10日
二重障壁強磁性トンネル接合および磁気デバイス

姜麗仙, 永沼博, 大兼幹彦, 安藤康夫

Property Type: Patent
ホイスラー合金材料、磁気抵抗素子および磁気デバイス

大兼幹彦, 佐藤丈, 窪田崇秀, 永沼博, 安藤康夫

Property Type: Patent
反平行結合膜構造体、トンネル磁気抵抗素子および磁気デバイス

大兼幹彦, 西村真之, 安藤康夫

Property Type: Patent
磁気抵抗素子及び磁気メモリ

西山勝哉, ファンウ, 水上成美, 宮崎照宣, 與田博明, 甲斐正, 岸達也, 渡邉大輔, 大兼幹彦, 安藤康夫, 吉川将寿, 永瀬俊彦, 北川英二, 大坊忠臣, 長嶺真夫

Property Type: Patent
磁性材料及びそれを用いた磁気抵抗素子

久保田均, 福島章雄, 薬師寺啓, 長浜太郎, 湯浅新治, 安藤功兒, 大兼幹彦, 渡邉美穂, 安藤康夫, 宮﨑照宣

Property Type: Patent
磁気抵抗素子の製造方法、磁気デバイスの製造方法、磁気抵抗素子の製造装置および磁気デバイスの製造装置

森田正, 小野一修, 菊地幸男, 大兼幹彦, 大坊忠臣, 安藤康夫, 宮﨑照宣

Property Type: Patent
トンネル磁気抵抗効果素子

大兼幹彦, 宮﨑照宣, 桜庭裕弥, 服部正志, 安藤康夫

Property Type: Patent
トンネル磁気抵抗効果素子

大兼幹彦, 宮﨑照宣, 桜庭裕弥, 服部正志, 安藤康夫

Property Type: Patent
低磁気緩和定数トンネル磁気抵抗素子

安藤康夫, 渡邉大輔, 大兼幹彦, 宮﨑照宣

Property Type: Patent
スピントランジスタ

大兼幹彦, 宮﨑照宣, 桜庭裕弥, 安藤康夫, 久保田均

Property Type: Patent
トンネル磁気抵抗効果素子

大兼幹彦, 宮﨑照宣, 桜庭裕弥, 安藤康夫, 久保田均

Property Type: Patent
磁気記録媒体

竹田克之, 清水雄二, 溝口康正, 安藤康夫

Property Type: Patent
磁気記録媒体

清水雄二, 竹田克之, 溝口康正, 安藤康夫

Property Type: Patent
磁気記録媒体

川上晃, 安藤康夫, 西川卓男, れん理英子, 枝松美紀

Property Type: Patent
磁気記録媒体

川上晃, 安藤康夫, 西川卓男, 瑓理英子, 枝松美紀

Property Type: Patent
磁気記録媒体およびその製造方法

瑓理英子, 安藤康夫

Property Type: Patent
磁気記録媒体

西川卓男, 安藤康夫

Property Type: Patent
磁気記録媒体

西川卓男, 安藤康夫

Property Type: Patent
磁気記録媒体

安藤康夫, 西川卓男

Property Type: Patent
磁気記録媒体

安藤康夫, 西川卓男

Property Type: Patent
磁気記録媒体

川上晃, 安藤康夫, 西川卓男, 瑓理英子, 枝松美紀

Property Type: Patent
磁気記録媒体

川上晃, 安藤康夫, 西川卓男, 瑓理英子, 枝松美紀

Property Type: Patent
磁気記録媒体

河原説子, 中野寧, 小山曻, 安藤康夫, 川上晃

Property Type: Patent
磁気記録媒体

西川卓男, 安藤康夫

Property Type: Patent
磁気記録媒体

安藤康夫, 見寶勉

Property Type: Patent
磁気記録媒体

松田敦子, 安藤康夫

Property Type: Patent
磁気記録媒体

松田敦子, 安藤康夫

Property Type: Patent
磁気記録媒体

後藤成人, 安藤康夫

Property Type: Patent
磁気記録媒体及びその製造方法

西川卓男, 安藤康夫

Property Type: Patent
磁気記録媒体

後藤成人, 安藤康夫

Property Type: Patent
磁気記録媒体

後藤成人, 安藤康夫

Property Type: Patent
磁気記録媒体

安藤康夫, 西川卓男

Property Type: Patent
磁気記録媒体

後藤成人, 安藤康夫

Property Type: Patent
磁気記録媒体

安藤康夫, 西川卓男

Property Type: Patent
磁気記録媒体

安藤康夫, 西川卓男

Property Type: Patent
磁気記録媒体の製造方法

川上晃, 安藤康夫

Property Type: Patent
磁気記録媒体の製造方法及びその装置

川上晃, 安藤康夫

Property Type: Patent
磁気記録媒体の製造方法

安藤康夫, 飛沢誠一

Property Type: Patent
磁気記録媒体の製造方法

佐々木邦綱, 安藤康夫, 飛沢誠一

Property Type: Patent
磁気記録媒体の製造方法

安藤康夫, 佐々木邦綱, 飛沢誠一

Property Type: Patent
磁気記録媒体

磯辺亮介, 安藤康夫

Property Type: Patent
磁気記録媒体

磯辺亮介, 安藤康夫

Property Type: Patent
磁気記録媒体

磯辺亮介, 安藤康夫

Property Type: Patent
磁気記録媒体

磯辺亮介, 安藤康夫

Property Type: Patent
磁気記録媒体の製造方法

奈良仁司, 川上晃, 松田敦子, 後藤成人, 安藤康夫

Property Type: Patent
磁気記録媒体の製造方法

奈良仁司, 見寶勉, 川上晃, 安藤康夫, 松田敦子

Property Type: Patent
磁気記録媒体の製造方法

奈良仁司, 見寶勉, 川上晃, 安藤康夫, 松田敦子

Property Type: Patent
磁気記録媒体の製造方法

奈良仁司, 見寶勉, 川上晃, 安藤康夫, 後藤成人

Property Type: Patent
磁気記録媒体の製造方法

川上晃, 奈良仁司, 見寶勉, 松田敦子, 安藤康夫

Property Type: Patent

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Research Projects 47

トンネル磁気抵抗素子を用いた心磁図および脳磁図と核磁気共鳴像の室温同時測定装置の開発 Competitive

安藤康夫

Offer Organization: 科学技術振興機構（ＪＳＴ）

System: 科学技術振興機構（ＪＳＴ）研究成果展開事業戦略的イノベーション創出推進プログラム（Ｓ－イノベ）

2011 - 2020
高機能・超低消費電力スピンデバイス・ストレージ基盤技術の開発 Competitive

大野英男

Offer Organization: 文部科学省

System: 「次世代ＩＴ基盤構築のための研究開発」「高機能・超低消費電力コンピューティングのためのデバイス・システム基盤技術の研究開発」

2007 - 2019
規則合金系ヘテロ接合における多彩な物理現象とスピンデバイス創製 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(S)

2012 - 2016
規則合金系ヘテロ接合における多彩なスピンデバイス創製(辞退） Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(A)

2012 - 2014
省エネルギー・スピントロニクス論理集積回路の研究開発 Competitive

大野英男

Offer Organization: (独)日本学術振興会

System: 日本学術振興会最先端研究開発支援プログラム

2009 - 2014
先端スピントロニクス材料と伝導現象（ASPIMATT） Competitive

安藤康夫

Offer Organization: (独)科学技術振興機構

System: (独)科学技術振興機構戦略的国際科学技術協力推進事業（共同研究型）研究領域「ナノエレクトロニクス」

2010 - 2012
MgOおよびAlOトンネル接合におけるスピントランスファー磁化反転 Competitive

安藤康夫

Offer Organization: (独)日本学術振興会日中科学技術協力事業共同研究

System: (独)日本学術振興会日中科学技術協力事業共同研究

2009 - 2011
材料インテグレーション国際教育研究拠点 Competitive

後藤孝

Offer Organization: 文部科学省

System: グローバルＣＯＥ

2007 - 2011
Design of Materials and Structures for Reduction in Spin Transfer Noise for Heusler Alloy Based CPP GMR Structures Competitive

安藤康夫

Offer Organization: 共同研究WDC

System: 共同研究WDC

2008 - 2010
金属ナノへテロ接合におけるスピン波励起と高周波デバイスの創製 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(A)(2)

2008 - 2010
Spin Current and Optical Properties

OHNO Yuzo, MUNEKATA Hiroo, ANDO Yasuo, NAGAOSA Naoto

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Priority Areas

Institution: Tohoku University

2007 - 2010

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On the spin current and optical properties, we investigated optical control and detection of electron and nuclear spin dynamics in semiconductor quantum structures, novel properties of ferromagnetic semidonductors with light irradiation, optical properties of the ferromagnetic metal multilayers, and theories of spin and light coupled phenomena. We obtained number of results on the spin current and optical properties, with collaboration between experimental and theoretical research groups.
磁性薄膜材料．MRAMの磁化反転に関する研究 Competitive

安藤康夫

Offer Organization: 寄付金

System: 寄付金

2007 - 2010
金属系多層膜におけるスピン流と磁気緩和 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金特定領域研究計画研究

2007 - 2010
NEDOスピントロニクス不揮発性機能技術プロジェクト Competitive

安藤功兒

Offer Organization: NEDO

System: NEDOスピントロニクス不揮発性機能技術プロジェクト

2006 - 2010
高密度情報ストレージコンポーネント，研究代表者 Competitive

宮﨑照宜

Offer Organization: 地域コンソーシアム研究開発事業

System: 地域コンソーシアム研究開発事業

1998 - 2010
高分極率を有する新しいホイスラー合金に関する研究 Competitive

安藤康夫

Offer Organization: (独)科学技術振興機構

System: (独)科学技術振興機構戦略的国際科学技術協力推進事業

2007 - 2009
New materials with High Spin Polarization Competitive

安藤康夫

Offer Organization: DFG Research Unit 559

System: DFG Research Unit 559

2007 - 2009
TMRセンサーに関する研究 Competitive

安藤康夫

Offer Organization: 一般受託研究

System: 一般受託研究

2007 - 2009
TMR材料の研究 Competitive

安藤康夫

Offer Organization: 共同研究費

System: 共同研究費

2007 - 2009
Development of magnetic tunnel junctions using Heusler alloy and observation of spin-injected magnetization reversal

MIYAZAKI Terunobu, ANDO Yasuo, KUBOTA Hitoshi, MIZUKAMI Shigemi, OOGANE Mikihiko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2005 - 2007

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1. Fabrication of magnetic tunnel junctions using epitaxial Heusler alooy electrodes Large tunnel magneto-resistance (TMR) ratios of 217% at room temperature and 753% at low temperature have been successfully observed in a magnetic tunnel junction (MTJ) using a high quality Heusler alloy electrode and an MgO crystalline barrier. The structure of the MTJ was Co2MnSi/MgO/CoFe. This observed TMR ratio is highest among the MTJs using Heusler alloy electrodes. Moreover, conductance-voltage property of the MTJ investigated in detail indicates that the origin of the large TMR was coherent tunneling process through the crystalline MgO barrier. 2. Micro-fabrication of MTJs and Observation of spin-injected magnetization reversal Spin-injected magnetization reversal has been successfully observed in the micro-fabricated CoFeB/MgO/CoFeB-MTJs using (Co_<50>Fe_<50>)_<100-x>B_x (x=20, 25, 30, thickness d=2 nm) switching layers. We found from this result that the switching current density depended on magnetization, damping constant and spin polarization of the ferromagnetic layer as expected by theory and reducing of magnetization and damping constant was quite effective to decrease the switching current density. 3. Magnetic damping constant α Magnetic damping constants in various ferromagnetic thin films were investigated systematically by FMR technique. Moreover, a measurement technique for estimation of damping constants in MTJs has been established. As a result, we found that the damping constant of 2nm thick CoFeB film was five times larger than that of bulk CoFeB and the neighboring layer of the switching layer influence the damping constant of the switching layer.
電子内部自由度制御型ナノデバイス創製原理の構築 Competitive

前川禎通

Offer Organization: (独)科学技術振興機構

System: 戦略的基礎研究推進事業CREST

2004 - 2007
New materials and features for spin-engineering Competitive

System: International Joint Research Projects

2004 - 2007
超ギガビット磁気メモリの基盤技術の開発 Competitive

宮﨑照宜

Offer Organization: 総務省

System: 総務省SCOOPプログラム

2003 - 2007
スピントロニクスデバイスに関する研究 Competitive

安藤康夫

Offer Organization: 一般受託研究費

System: 一般受託研究費

2007 -
共鳴磁気トンネル・ナノドット不揮発性メモリの創製 Competitive

小柳光正

Offer Organization: (独)科学技術振興機構

System: 戦略的創造研究推進事業CREST

2002 - 2006
高機能・超低消費電力メモリの開発 Competitive

大野英男

Offer Organization: 文部科学省

System: 文部科学省ITプログラム

2002 - 2006
微細加工した強磁性トンネル接合の動的磁区構造と磁化反転特性 Competitive

安藤康夫

Offer Organization: (独)日本学術振興会

System: (独)日本学術振興会日中科学技術協力事業共同研究

2004 - 2005
スピンバッテリーの強磁性共鳴を用いた動作実証 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金萌芽研究

2004 - 2005
微小強磁性トンネル接合のスピンダイナミクス Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(A)(2)

2003 - 2005
固体中へのスピン注入による新機能創製 Competitive

鈴木義茂

Offer Organization: (独)科学技術振興機構

System: 戦略的基礎研究推進事業CREST

2000 - 2004
(独)日本学術振興会日韓科学技術協力事業共同研究 Competitive

安藤康夫

Offer Organization: (独)日本学術振興会

2002 - 2003
Spin injection into high quality small magnetic tunnel junctions

MIYAZAKI Terunobu, SUZUKI Yoshishige, KUBOTA Hitoshi, ANDO Yasuo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2001 - 2003

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A process for fabricating small magnetic tunnel junctions (MTJs) by using focused ion beam (FIB)-assisted chemical vapor deposition was investigated. Deposited tungsten was used as an electrode, and deposited carbon or tungsten was used as a mask. MTJs with a junction area of 400 x 400 nm^2 showed a tunnel magneto-resistance (TMR) ratio of about 30 % at room temperature. An apparatus for MR measurement of small MTJs by using conductive AEM was set up. The MR ratio for the junction with 2 x 0.7 μm-2 was 29%. Ferromagnetic resonance (FMR) spectra were measured for the Cu/Al-oxide/FeNi/Cu multilayers. Both FMR and the electrical detected microwave resonance (EDMR) spectra suggested that the spin was injected into non-magnetic metal layers due to the spin current generated by the spin precession. For the electrical detection of the magnetization reversal, a homemade probing apparatus. using air-coplanar probes was set up. A pulse generator was used to create current pulses with less than 500 ps rise time through the upper electrode of the MTJs. The time to switch the magnetization decreased to 500 ps with increasing the field pulse amplitude up to 100 Oe with no hard axis field. The time to switch the magnetization became short and the reversal became clear with increasing the hard axis field. The transition time estimated using Landau-Lifshitz-Gilbert (LLG) equation of motion of the exact experimental conditions agreeded well with the experimental measurements. Magnetization precession of NM/FeNi/NM (NM=Cu and Pt) multilayers was measured by time-resolved magneto-optical Kerr effect (MOKE). The MOKE measurement system equipped with a pulse laser, optical delay lines was set up and samples were combined with photoconductive switch for pulse filed generation. Clear oscillation and relaxation of the magnetization of motion in time domain were successfully observed. Gilbert damping constant α for Cu/FeNi/Cu multilayers was independent of the thickness of feNi. While α for Pt/FeNi/Pt multilayers was enhanced as FeNi layer was thinner. These experimental data were well fitted by LLG-calculation with the same α obtained by ferromagnetic resonance.
スピンバルブタイプTMRを利用した高感度再生用ヘッド素子 Competitive

宮﨑照宜

Offer Organization: 情報ストレージ研究推進機構（SRC）

System: 情報ストレージ研究推進機構（SRC）

1995 - 2003
Trial Fabrication and Evaluation of Spin Tunnel Magnetoresistive Device

KUBOTA hitoshi, KUMAGAI Seiji, MIYAZAKI Terunobu, ANDO Yasuo, NAKASHIO Eiji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2001 - 2002

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Development of micro-fabrication processes of small magnetic tunnel junctions (MTJs) using focused ion beam induced deposition (FIBID) has been examined. FIBID technique was applied to make small carbon or tungsten patterns, those were used as Ar etching masks and/or electrical leads. The deposition tecnique has some advantages: Pattern location can be controlled freely and precisely, pattem shaps a easily designed, pattem height can be controlled widely, and sub-micron patterns should ha easily fabricated. The smallest lateral size of the carbon and tungsten mask patterns deposited were about 100 nm and 140 nm, repectively. The C mask patterns were hard for Ar etching and soft for O_2 ashing. Resistivity of the Wpatterns was enough small, thus, the W patterns can be used as electrical leads. MTJs were fabricated using C masks or W masks/leads. During Ar ion etching, redeposition at side walls of the mask patterns were formed, resulted in short-circuiting. It is necessary to avoid the redeposition to establish the fabrication process of small MTJs using FIBID technique. To improve the quality of insulating layers in MTJs, we have used epitaxially grown Ag/Cu/Ni-Fe films on Si (111) substrates as bottom electrodes. Epitaxial growth of the trilayers was confirmed using X-ray diffraction and low energy electron diffraction. The MTJs fabricated showed large tunnel magnetoresistance (TMR) ratios of about 50%. The bias dependence of the TMR ratio was greatly improved in those MTJs. The insulating layers grown on the epitaxial bottom electrodes would have fewer defects than the those grown on textured bottom electrodes. Further experiments are necessary to complete the fabrication process to apply to the MTJs with epitaxially grown bottom electrodes. The switching characteristics of epitaxially grown MTJs with an area of about 100 nm square would be investigated.
プローブ顕微鏡探針からの弾道電子放出による局所トンネルスピン伝導 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(C)(2)

2001 - 2002
ナノサイズ強磁性トンネル接合への高密度スピン注入 Competitive

安藤康夫

Offer Organization: (財)三菱財団

System: (財)三菱財団自然科学研究助成

2002 -
Development of Spin Tunnel Magnetoresistive Read Head

MIYAZAKI Terunobu, KUMAGAI Seiji, KUBOTA Hitoshi, ANDO Yasuo, SUGAWARA Junichi, NAKASHIO Eiji

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for University and Society Collaboration

Institution: Tohoku University

1999 - 2001

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Spin tunnel junction is one of the potential candidate for highly sensitive magnetic read head. However, in practical use, there are some difficulties to be overcome : large noise, low data transfer rate, and difficulty in applying magnetic bias fields. The first and the second problerns are due to large junction resistance and the third one is due to the characteristic junction geometry which is much different from metallic GMR head geometry. In this research project, the research group in Graduate School of Engineering, Tohoku university, together with the group in SONY Corporation have made experimental research to overcome these difficulties. The Tohoku University group engaged in the fabrication of low tunnel resistance junctions by thinning insulating films in the junctions. Local transport properties of the insulating layers were examined using conductive atomic force microscopy (c-AFM). It has been concluded that the insulating layers less than 0.8 nm contain defects, which cause the reduction of tunnel magnetoresistance (TMR) ratios. It has been also made clear that oxygen content in the insulating layer becomes homogeneous in the annealing process, resulted in the increase of the TMR ratios. In order to reduce the number of defects in the insulating layer, various kinds of materials were investigated as buffer layers. In conclusion, a low resistance value (about 80 Ω・um^2) and a high TMR (30%) were obtained using Cu buffer layer and 0.6 nm thick Al in the insulating layer. In case of Ni-Fe buffer layer, it is possible to reduce the resistance further keeping high TMR ratios. The SONY group engaged in the development of read head design for the spin tunnel junctions. Flux guide was adopted in the head to avoid the mechanical damage on the junction and also to increase the junction area. The permanent magnet bias method, which is commonly used in GMR read head, causes electrical short circuiting in spin tunnel magnetoresistive read head. Therefore, a long range exchange coupling biasing scheme was employed to apply a bias field to the flux-guide. The reading performance of a test head was measured in a stationary head/metal tape configuration using helical scanning system. The output signal increased up to 1.75 mV_<p-p>, which was corresponding to +2.4 dB output of a conventional read head. In conclusion it has been demonstrated that the flux-guide type structure combined with a long-range exchange bias method is feasible for spin tunnel magnetoresistive read head.
Fabrication process for hybrid magnetic material and fabrication of tunnel magnetoresistive read head

MIYAZAKI Terunobu, KUMAGAI Seiji, KUBOTA Hitoshi, ANDO Yasuo, NAKATANI Isao

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

1999 - 2001

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In order to fabricate a read head using tunnel magnetoresistive junction, optimization of the tunnel junction (layered structure, stacking sequence, optimal annealing condition, thickness of barrier layer) and micro-fabricating process have been studied. Two kinds of read head were successfully demonstrated. The main results are summarized as follows. 1. The Ta30(Å)/Ni_<80>Fe_<20>(30Å)/Cu(200Å)/IrMn(100Å)CoFe(40Å)/Al-oxide/CoFe(40Å)/Ni_<80>Fe_<20>(200Å)/Ta(50Å) junction annealed at 250 ℃ for 1 h exhibited that the values of resistance times cross section and tunnel magnetoresistance ratio were 78 Ω・μm^2 and 33 %, respectively. 2. Using the photolisography and Ar ion milling process, we fabricated a small junction with 3x3 μm^2. On the other hand, small junction with 0.5x0.5 μm^2 was obtained by using electron beam lithography and no damage was confirmed for the junction by comparing the transport property measured before and after micro fabrication. 3. Feasibility of tunnel magnetoresistive read head with flux-guide layers was investigated for helical-scan tape storage applications. A long-range exchange coupling bias scheme, with a Cu layer and an antiferromagnet were deposited on top of free layer in the tunnel-valve element, was employed. In order to stabilize domain structures in the free layer, the long range exchange coupling biasing was combined with conventional permanent magnet bias method. The maximum output voltage of the flux guide type reader was 1.75 mV_<p-p> which was corresponding to +1.5 dB of a conventional anisotropic magnetoresistive reader. Furthermore, a tunnel magnetoresistive read head for HDD application was fabricated and an out put voltage corresponding to 10 Gb/inch^2 was realized.
有機・無機ペロブスカイトナノ構造薄膜における光誘起による磁性と伝導に関する研究 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金基盤研究(C)(2)

1997 - 2000
Competitive

安藤康夫

Offer Organization: (財)住友財団

System: (財)住友財団基礎科学研究助成金

2000 -
有機・無機ペロブスカイトナノコンポジットにおける光誘起による磁性と伝導に関する研究 Competitive

安藤康夫

Offer Organization: (財)旭硝子財団

System: (財)旭硝子財団自然科学系研究助成

1999 -
希土類超薄膜のスピン構造と磁気光学スペクトル

宮崎照宜, 安藤康夫

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 萌芽的研究

Institution: 東北大学

1997 - 1998

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1. 低温,高磁界中表面磁気光学効果測定装置の製作製作した装置の主な仕様は,(1)最大印加磁界:20kOe,(2)測定温度保持時間:10時間以上,(3)到達最低温度:12Kである.これを達成するために,マグネットのポールピースをクライオスタットの内部に挿入した形状に設計した.製作した低温,高磁界中表面磁気光学効果測定装置の動作検証を行い,以下の結果を得た. (1) Ni薄膜を用い磁気光学スペクトルを測定した.圧縮冷凍機動作時の機械的振動が測定に問題ないことを確認した. (2) 試料ホルダー上の温度を測定し,設定温度に対して1度以内の精度に10分以内で制御できた. (3) 光導入用の石英窓をマグネットヨークの外側に配置し,漏れ磁界によるバックグラウンドシフトの影響がほとんどないことを確認した. 2. Gd薄膜の作製と磁気光学スペクトルガラス基板上に5×10^<-10>Torrの超高真空中電子ビーム蒸着法でGd薄膜(1000,250Å)を作製した.膜表面に酸化防止膜としてMgF_2を100Åコーティングした.この磁気光学スペクトルおよび磁化曲線を測定した.結果は以下の通りである. (1) カーヒステリシスの温度依存性を測定した.カー回転角および保磁力の温度依存性は磁気特性測定の結果と対応した. (2) 測定温度20〜350Kで磁気光学スペクトルを得た.伝導率スペクトルの非対角成分σ_<xy>"のスペクトルにおいて,バルクの報告と比較してシャープなピークが1.9eVのエネルギー位置に見られた.これはフェルミレベル付近から,分裂したdバンドへの遷移に対応する.膜厚250Åのスペクトルは,1000Åの場合と比較して構造的な変化は特に観測されなかった.
Study on Spin transport Devices

MIYAZAKI Terunobu, KUBOTA Hitoshi, ANDO Yasuo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

1996 - 1998

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In order to fabricate spin devices using tunnel magnetoresistant effect, we carried out the research on fundamental physical mechanism for tunnel junctions, on the development a measuring instrument for the interfacial structure and on the micro-fabricating process for microstructured junctions. The main results are summarized as follows. 1. Fundamental physical properties The tunnel magnetoresistance (TMR) effect in the Ferro/Insulator/Ferro junctions depends not only the spin-polarizations of electrodes (ferromagnets) but also on the barrier height and width of insulator. These dependences were confirmed by systematic experiments and by comparison with theoretical treatments reported by other groups. Also, the temperature and applied voltage dependence of TMR ratio were investigated in detail. Spin-valve type junctions with exchange-biasing one of the magnetic layers using a thin antiferromagnetic FeMn or IrMn layer were prepared. These junctions exhibited an well defined switching field, temperature insensitive TMR ratio and improved the applied voltage dependence of the TMR ratio.2. Fabrication of measuring apparatus In order to analyze the interfacial structure of the tunnel junctions, inelastic electron tunnel spectroscopy (IETS) apparatus was developed. By using the apparatus IET spectrum for many kind of the junctions were examined and the usefulness of the analysis was proved. Furthermore, a Kerr hysteresis apparatus for measuring a small area of the tunnel junction was made. By using the apparatus it was shown that the magnetization process of 40*40 mum^2 junction area corresponds well to the magnetoresistance curve of the junction. 3. Micro-fabrication process and microstructured tunnel junction By using photolithography and Ar ion milling, the process to fabricate a small tunnel junction was investigated. A redeposited free junction was made by choosing the optimum incident angle of Ar ions and milling depth. A small contact hole at the center of active junction area was well made by plasma etching with CF_4 gases. By using the processes, a junction with 3*3mum2 active area, 500OMEGA tunnel resistance and 15% TMR ratio was successfully made. The tunnel junction possesses a high potential for magnetic reading head for high density magnetic recording and/or magnetic random access memory.
層状ペロブスカイト構造を有する有機・無機ナノコンポジット薄膜における光誘起による磁性と伝導に関する研究 Competitive

安藤康夫

Offer Organization: (財)泉科学技術振興財団

System: (財)泉科学技術振興財団研究助成金

1998 -
分子構造の制御されたLB膜を用いたMIM接合の磁気トンネリング効果に関する研究 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金重点領域研究

1995 - 1997
高分子LB膜を用いた金属/絶縁体/金属接合の作製と磁気トンネリング効果に関する研究 Competitive

安藤康夫

Offer Organization: (財)日産科学振興財団

System: (財)日産科学振興財団奨励研究助成金

1995 -
LB法による有機磁性薄膜の作製並びに基礎物性に関する研究 Competitive

安藤康夫

Offer Organization: 文部科学省

System: 科学研究費補助金奨励研究(A)

1994 -

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Social Activities 63

応用物理学会リフレッシュ理科教室

2001/08/07 - 2001/08/08

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仙台市の中学生を対象に理科教室を開いた
医療センサーのベンチャー東北大教授ら設立上場目指す

日本経済新聞

2018/12/04 -
東北大，磁気センサー技術のベンチャー企業設立

OPTRONICS ONLINE

2018/12/03 -
＜東北大＞医療用センサー開発へベンチャー設立高度な診断を容易に、５年後上場目指す

河北新聞

2018/12/03 -
医療用センサー開発へベンチャー設立

東北放送，Nスタみやぎ

2018/11/30 -
液体ヘリウムを使わず簡単に低コストで脳磁場を測定する高感度センサーを開発

JSTnews

2018/02 -
脳・心磁場計測用の「TMR素子生体磁気センサ

MED+Fit

2018/01/17 -
コニカミノルタ東北大学と脳磁場を簡便に低コストで計測する高感度センサを開発

インナービジョン

2018 -

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インナービジョン第33巻第１号 2018 JANUARY
コニカミノルタ、脳磁場を簡易に低コストで計測する高感度センサを開発～心磁場測定の高速化も同時に実現－革新的な医用計測技術～

映像情報Medical

2018 -

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映像情報Medical Vol.50 No.1 JANUARY 2018
トンネル磁気抵抗素子を用いた心磁図及び脳磁図と核磁気共鳴像の室温同時測定装置の開発

東北大学レアメタル・グリーンイノベーション研究開発センターフォーラム2017　東北大学レアメタル・グリーンイノベーション研究開発センター

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平成27年度第5学年「2015 出前授業」　仙台市立泉松陵小学校

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病院新聞

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新潟高校模擬講義　新潟県立新潟高等学校

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TMR磁気センサを高感度化・低ノイズ化、α波の検出に成功－東北大, 医療

NEWS QLifePro

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東北大学、簡便かつ低コストで脳磁場を計測する高感度センサを開発

Answers

2017/11/27 -
診療所レベルでの脳磁場測定へ - 東北大、液体Heを使わない新センサを開発

マイナビニュース

2017/11/27 -
脳・心臓の磁場、室温で簡易計測東北大・コニカミノルタなどが手法開発

日刊工業新聞オンライン

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コニカミノルタ、東北大と脳磁場を簡便に低コストで計測する高感度センサーを開発

MORNINGSTAR

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脳・心臓磁場を簡易計測東北大・コニカミノルタなど、室温利用センサー作製

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東北大とコニカミノルタ、脳磁場を安価に計測できる高感度センサを開発

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脳磁場を簡便に低コストで計測する高感度センサを開発

J-Net21

2017/11/24 -
コニカミノルタ／東北大との共同研究で脳磁場を簡便に低コストで計測する高感度センサを開発

月刊新医療

2017/11/24 -
磁石を使うと心臓や脳の状態がわかる？

サイエンススクール　生出中学校

2017/11/21 -

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磁石を使うと心臓や脳の状態がわかる？
生体活動情報を磁場で捉える高感度磁場センシング装置

JSTフェア2017　東京

2017/08/31 -

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(展示)
室温脳磁計による脳機能のワイドバンドマッピング

第3回みやぎみやぎ医療機器創生産学官金連携フェア　仙台

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認知症予防にも期待、室温動作の生体磁場センサ高出力化に成功

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生体磁場センサーの高出力化に成功、MRIイメージングとの同時測定も

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心臓や脳の検査、気軽にできる環境へ

QLifePro 医療ニュース

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室温で動作するMTJ生体磁場センサの高出力化に成功

医療NEWS

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東北大，室温動作の生体磁場センサーを高出力化

OPTRONICS ONLINE

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室温で動作する生体磁場検出用センサで従来素子の1500倍の出力

マイナビニュース

2017/05/22 -
東北大、室温動作の生体磁場センサの高出力化に成功

日本経済新聞

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室温脳磁計による脳機能のワイドバンドマッピング

知と医療機器創生宮城県エリア総括報告会　仙台

2017/03/02 -
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平成28年度第5学年「2016出前授業」　仙台市立錦ヶ丘小学校

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磁石を使って体内を見る！

平成28年度第5学年「2016出前授業」　仙台市立幸町小学校

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新潟高校模擬講義　新潟県立新潟高等学校

2016/07/08 -
磁石を使って体内を見る！

平成27年度第5学年「2015 出前授業」　仙台市立住吉台小学校

2015/12/01 -
特別授業「スピンを用いた最先端デバイスの開発～工学とは，医工学とは～」を行った

第１学年「大学出張講義」宮城県立宮城県泉高等学校

2014/11/12 -
トンネル磁気抵抗素子を用いた心磁図および脳磁図と核磁気共鳴像の室温同時測定装置の開発

東北大学イノベーションフェア2014　仙台国際センター

2014/01/28 -
「微小磁石を用いた生体磁場センサの開発－ナノテク材料から最先端機器開発の方法－」

東北大学進路講演会　神奈川県立小田原高等学校

2013/11/26 -
｢磁石の神秘｣

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2013/11/12 -
｢磁石で考えるナノテクの世界｣

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｢磁石の不思議にふれてみよう！｣

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平成25年度ユニバーサイエンス　学校法人ノートルダム新潟清心学園新潟清心女子高等学校

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「科学の不思議を体験しよう」

平成25年度リフレッシュ理科教室　仙台市立中野小学校

2013/06/28 -
平成２４年度東北地区高等専門学校専攻科産学連携シンポジウム

2013/03/03 -
｢磁石の神秘｣

2012/12/17 -
東北大が開発に成功超高密度HDD用巨大磁気抵抗素子

科学新聞

2011/10/21 -
東北大学、超高密度ハードディスク用の巨大磁気抵抗素子を開発超高密度ハードディスク用巨大磁気抵抗素子の開発に成功－１平方インチ当たり５テラビット容量の次世代ハードディスクに適用可能な技術－

日経プレスリリース

2011/09/30 -
東北大，1平方インチ当たり5Tbクラスの次世代HDDヘッド用素子を開発

財経新聞

2011/09/30 -
東北大、5Tビット/平方インチの記録が可能となるHDD用磁気抵抗素子を開発

マイコミジャーナル

2011/09/30 -
HDD，記録密度7倍に東北大，新型の磁気ヘッド

日経産業新聞

2011/09/30 -
磁石で考えるナノテクの世界～最先端電子デバイスと支えるナノサイエンス～オープンキャンパス模擬授業

オープンキャンパス模擬授業

2009/07/31 -
磁化ダイナミクスとスピントロニクス

2008/08/01 -
磁石で考えるナノテクの世界～最先端電子デバイスと支えるナノサイエンス～

2008/07/31 -
最先端技術と産業を支える工学研究～磁石で考えるナノテクノロジー～

2008/03/03 -
メモリのデバイス原理と研究開発動向

2007/04/26 -

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｢MRAMの研究開発動向｣
高大連携特別授業

2006/08/01 -

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特別授業を行った
スピンを用いた最先端デバイスの開発～ナノテクから生体医工まで～｣（理数セミナーⅠ）

平成25年度模擬授業　山形県立鶴岡南高等学校

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｢

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Other 27

先端スピントロニクス材料と伝導現象（ASPIMATT）

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先端スピントロニクス材料と伝導現象（ASPIMATT）に関する研究
MgOおよびAlOトンネル接合におけるスピントランスファー磁化反転

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MgOおよびAlOトンネル接合におけるスピントランスファー磁化反転
スピントロニクスデバイスに関する研究

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スピントロニクスデバイスに関する研究
Design of Materials and Structures for Reduction in Spin Transfer Noise for Heusler Alloy Based CPP GMR Structures

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Design of Materials and Structures for Reduction in Spin Transfer Noise for Heusler Alloy Based CPP GMR Structures
高分極率を有する新しいホイスラー合金に関する研究

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高分極率を有する新しいホイスラー合金に関する研究
New materials with High Spin Polarization

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New materials with High Spin Polarization
高機能・超低消費電力スピンデバイス・ストレージ基盤技術の開発

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高機能・超低消費電力スピンデバイス・ストレージ基盤技術の開発
磁性薄膜材料．MRAMの磁化反転に関する研究

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磁性薄膜材料．MRAMの磁化反転に関する研究
TMR材料の研究

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TMR材料の研究
TMRセンサーに関する研究

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TMRセンサーに関する研究
スピントロニクスデバイスに関する研究

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スピントロニクスデバイスに関する研究
NEDOスピントロニクス不揮発性機能技術プロジェクト

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NEDOスピントロニクス不揮発性機能技術プロジェクト
スピンエンジニアリングのための新材料と新機能

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スピンエンジニアリングのための新材料と新機能
微細加工した強磁性トンネル接合の動的磁区構造と磁化反転特性

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微細加工した強磁性トンネル接合の動的磁区構造と磁化反転特性
電子内部自由度制御型ナノデバイス創製原理の構築

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電子内部自由度制御型ナノデバイス創製原理の構築
超ギガビット磁気メモリの基盤技術の開発

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超ギガビット磁気メモリの基盤技術の開発
ナノサイズ強磁性トンネル接合への高密度スピン注入

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ナノサイズ強磁性トンネル接合への高密度スピン注入
強磁性トンネル接合の耐熱特性改善に関する研究

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強磁性トンネル接合の耐熱特性改善に関する研究
高機能・超低消費電力メモリの開発

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高機能・超低消費電力メモリの開発
共鳴磁気トンネル・ナノドット不揮発性メモリの創製

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共鳴磁気トンネル・ナノドット不揮発性メモリの創製
固体中へのスピン注入による新機能創製

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固体中へのスピン注入による新機能創製
走査型プローブ顕微鏡を用いた強磁性トンネル接合の局所磁気抵抗効果に関する研究

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走査型プローブ顕微鏡を用いた強磁性トンネル接合の局所磁気抵抗効果に関する研究
有機・無機ペロブスカイトナノコンポジットにおける光誘起による磁性と伝導に関する研究

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有機・無機ペロブスカイトナノコンポジットにおける光誘起による磁性と伝導に関する研究
層状ペロブスカイト構造を有する有機・無機ナノコンポジット薄膜における光誘起による磁性と伝導に関する研究

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層状ペロブスカイト構造を有する有機・無機ナノコンポジット薄膜における光誘起による磁性と伝導に関する研究
高密度情報ストレージコンポーネント

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高密度情報ストレージコンポーネント
高分子LB膜を用いた金属/絶縁体/金属接合の作製と磁気トンネリング効果に関する研究

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高分子LB膜を用いた金属/絶縁体/金属接合の作製と磁気トンネリング効果に関する研究
スピンバルブタイプTMRを利用した高感度再生用ヘッド素子

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スピンバルブタイプTMRを利用した高感度再生用ヘッド素子

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