TOHOKU UNIVERSITY Researchers

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Yoshichika Otani

Section

Graduate School of Science

Job title

Professor

researchmap

https://researchmap.jp/yotaniissp

J-GLOBAL ID

201801011736510286

ORCID

https://orcid.org/0000-0001-8008-1493

Profile

1989年慶應義塾大学大学院理工学研究科博士課程（物理学専攻）修了、理学博士。同年4月より1991年までアイルランド・ダブリン大学トリニティーカレッジ博士研究員、1991年より1993年までフランス・ルイ・ネール磁性物理学研究所研究員、1993年慶應義塾大学理工学部助手、1995年東北大学大学院工学研究科助教授。2002年より理化学研究所フロンティア研究システムに所属し、2007年より同基幹研究所量子ナノ磁性研究チーム・チームリーダー、2013年から2025年3月まで同創発物性科学研究センター（CEMS）量子ナノ磁性研究チーム・チームリーダーを務めた。2004年より2026年3月まで東京大学物性研究所ナノスケール物性研究部門教授を兼任。2026年3月末日をもって東京大学を退職し、同年4月1日より東北大学大学院理学研究科物理学専攻卓越教授。専門はスピントロニクス、磁性体物理、ナノスケール磁性体および半導体・超伝導体との複合構造の電子・磁気物性。

Research History 1

2013/04 - 2025/03

RIKEN　Center for Emergent Matter Science　Team Leader

Research Areas 1

Natural sciences / Magnetism, superconductivity, and strongly correlated systems / Magnonics

Papers 265

Crossover between intrinsic and temperature-assisted regimes in spin-orbit torque switching of antiferromagnetic order Peer-reviewed

Takumi Matsuo, Tomoya Higo, Hanshen Tsai, Daisuke Nishio-Hamane, Takuya Matsuda, Ryota Uesugi, Kouta Kondou, Shinji Miwa, Yoshichika Otani, Satoru Nakatsuji

Nature Communications　17　(1)　2026/07/13
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41467-026-74311-6 　

eISSN： 2041-1723
Anomalous Nernst Effect of FeCoNi-based High-Entropy Alloy Ferromagnetic Thin Films

Hironari Isshiki, Kazuya Z. Suzuki, Masaki Imai, Zijian Dong, Hiroyuki Chudo, YoshiChika Otani, Koki Takanashi, Jun’ichi Ieda

High Entropy Alloys & Materials　2026/03/31
Publisher: Springer Science and Business Media LLC
DOI： 10.1007/s44210-026-00078-6 　

ISSN： 2731-5819

eISSN： 2731-5827

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Abstract High-entropy alloys, defined as single-phase solid solutions composed of five or more elements, have attracted considerable attention for their exceptional mechanical properties. However, their electronic and magnetic transport properties remain largely unexplored. In this study, we focus on the anomalous Nernst effect, a magnetic thermoelectric phenomenon, in FeCoNi-based ferromagnetic high-entropy alloy thin films at room temperature. We systematically examined the influence of heavy-element concentration in FeCoNiCuPd. Increasing the Pd content to 10, 20, and 30 at% led to the anomalous Nernst conductivity of 0.53, 0.61, and 0.74 A m ⁻¹ K, respectively, attributable to the strong spin–orbit coupling of Pd. These results indicate that adding heavy elements effectively enhances transverse transport in high-entropy alloys. To further enhance the anomalous Nernst effect, we introduced an even heavier element, Pt, into the alloy. The resulting FeCoNiPdPt thin film exhibited a high anomalous Nernst conductivity of ~ 0.97 A m ⁻¹ K ⁻¹ together with a large anomalous Nernst thermopower of ~ 0.9 µV K ⁻¹ , demonstrating the thermoelectric potential of these alloys.
Harmonic and subharmonic magnon generation in a surface-acoustic-wave resonator Peer-reviewed

Yunyoung Hwang, Liyang Liao, Jorge Puebla, Marco Brühlmann, Carlos Gonzalez-Ballestero, Kouta Kondou, Naoki Ogawa, Sadamichi Maekawa, Yoshichika Otani

Physical Review Applied　25　(3)　2026/03/17
Publisher: American Physical Society (APS)
DOI： 10.1103/mm21-ctsb 　

eISSN： 2331-7019
The 2026 guided acoustic waves roadmap

Hubert J Krenner, Paulo V Santos, Christoph Westerhausen, Gustav Andersson, Andrew N Cleland, Hermann Sellier, Shintaro Takada, Christopher Bäuerle, Daniel Wigger, Tilmann Kuhn, Paweł Machnikowski, Matthias Weiß, Galan Moody, Alberto Hernández-Mínguez, Snežana Lazić, Alexander S Kuznetsov, Matthias Küß, Manfred Albrecht, Mathias Weiler, Jorge Puebla, Yunyoung Hwang, Yoshichika Otani, Krishna C Balram, I-Tung Chen, Keji Lai, Mo Li, Geoff R Nash, Emeline D S Nysten, Paromita Bhattacharjee, Himakshi Mishra, Parameswar K Iyer, Harshal B Nemade, Abdelkrim Khelif, Sarah Benchabane, Gao Feng, Yabin Jin, Ausrine Bartasyte, Samuel Margueron, Massimiliano Marangolo, Laura Thevenard, Pauline Rovillain, Catherine Gourdon, Sami Hage-Ali, Omar Elmazria, Hagen Schmidt, Leslie Y Yeo, Lizebona A Ambattu, Jessie S Jeon, Daesik Kwak, Joseph Rufo, Shujie Yang, Tony Jun Huang

Journal of Physics D: Applied Physics　59　(9)　093001-093001　2026/03/02
Publisher: IOP Publishing
DOI： 10.1088/1361-6463/ae258d 　

ISSN： 0022-3727

eISSN： 1361-6463

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Abstract Guided elastic waves are a truly cross-disciplinary key enabling technology. For more than five decades, surface acoustic wave (SAW) and bulk acoustic wave devices find widespread applications. Nowadays, different types of guided elastic waves cover the wide spectrum of applications spanning from quantum technologies to the life sciences, from controlling single excitations to macroscopic collective states in condensed matter. Six years after the first 2019 SAW roadmap, we believe it is time to make a step back and take a fresh look at the status of the field and its future challenges. Since the first roadmap in 2019, the spectrum clearly expanded and this new edition presents a current snapshot of the status of this vibrant field and prospects for potential future developments.
Observation of chiral domain walls in an octupole-ordered antiferromagnet

Moeta Tsukamoto, Zhewen Xu, Tomoya Higo, Kouta Kondou, Kento Sasaki, Mihiro Asakura, Shoya Sakamoto, Pietro Gambardella, Shinji Miwa, YoshiChika Otani, Satoru Nakatsuji, Christian L. Degen, Kensuke Kobayashi

Physical Review B　112　(2)　2025/07/17
Publisher: American Physical Society (APS)
DOI： 10.1103/njnm-nl6n 　

ISSN： 2469-9950

eISSN： 2469-9969
Electrical detection of interfacial exchange field at the (ferromagnetic insulator) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mrow> <mml:mo>|</mml:mo> </mml:mrow> </mml:mrow> </mml:math> (normal metal) interface using spin-dependent scattering

Prasanta Kumar Muduli, Naëmi Leo, Mingran Xu, Zheng Zhu, Jorge Puebla, Christian Ortiz Pauyac, Hironari Isshiki, YoshiChika Otani

Journal of Physics D: Applied Physics　58　(28)　285003-285003　2025/07/11
Publisher: IOP Publishing
DOI： 10.1088/1361-6463/ade691 　

ISSN： 0022-3727

eISSN： 1361-6463

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Abstract The spin–orbit field and interfacial exchange field (IEF) are two major interface phenomena, and the detection and manipulation of these fields can enable a variety of nanoscale spintronics devices. Optimizing the IEF, which governs the spin-dependent scattering asymmetry at (ferromagnetic insulator)|(normal metal) interfaces, will pave the way for next-generation nanoscale, low-power insulator spintronics devices. Here, we demonstrate an experimental pathway to detect an IEF between insulating ferromagnet EuS and non-magnetic Cu using magnetoresistance (MR) measurements, and show that the spin-dependent scattering at the common interface can lead to a significant current-in-plane MR in Py Cu EuS trilayer Hall-bar device. Our experiment suggests that simple magnetoresistance measurements can be used to experimentally detect the IEF and thereby the magnetic state of a ferromagnetic insulator.
Nonlocal electrical detection of reciprocal orbital Edelstein effect

Weiguang Gao, Liyang Liao, Hironari Isshiki, Nico Budai, Junyeon Kim, Hyun-Woo Lee, Kyung-Jin Lee, Dongwook Go, Yuriy Mokrousov, Shinji Miwa, Yoshichika Otani

Nature Communications　16　(1)　2025/07/10
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41467-025-61602-7 　

eISSN： 2041-1723

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Abstract The orbital Edelstein effect and orbital Hall effect, where a charge current induces a nonequilibrium orbital angular momentum, offer a promising method for efficiently manipulating nanomagnets using light elements. Despite extensive research, understanding the Onsager’s reciprocity of orbital transport remains elusive. In this study, we experimentally demonstrate the Onsager’s reciprocity of orbital transport in an orbital Edelstein system by utilizing nonlocal measurements. This method enables the precise identification of the chemical potential generated by orbital accumulation, avoiding the limitations associated with local measurements. We observe that the direct and inverse orbital-charge conversion processes produce identical electric voltages, confirming Onsager’s reciprocity in orbital transport. Additionally, we find that the orbital decay length, approximately 100 nm at room temperature, is independent of the Cu thickness and decreases with decreasing temperature, revealing a distinct contrast to the spin transport behavior. Our findings provide valuable insights into both the reciprocity of the charge-orbital interconversion and the nonlocal correlation of orbital degree of freedom, laying the ground for orbitronics devices with long-range interconnections.
Nonreciprocal resonant surface acoustic wave absorption in Y3⁢Fe5⁢O12

You Ba, Jorge Puebla, Kei Yamamoto, Yunyoung Hwang, Liyang Liao, Sadamichi Maekawa, Olivier Klein, Yoshichika Otani

Physical Review B　111　(10)　2025/03/03
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevb.111.104401 　

ISSN： 2469-9950

eISSN： 2469-9969
Nonreciprocal magnetoacoustic waves with out-of-plane phononic angular momenta

Liyang Liao, Fa Chen, Jorge Puebla, Jun-ichiro Kishine, Kouta Kondou, Wei Luo, Degang Zhao, Yue Zhang, You Ba, Yoshichika Otani

Science Advances　10　(28)　2024/07/12
Publisher: American Association for the Advancement of Science (AAAS)
DOI： 10.1126/sciadv.ado2504 　

eISSN： 2375-2548

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Surface acoustic wave (SAW) can carry phononic angular momentum, showing great potential as an energy-efficient way to control magnetism. Still, out-of-plane phononic angular momentum in SAW and its interaction with magnetism remain elusive. Here, we studied the SAW-induced magnetoacoustic waves and spin pumping in Ni-based films on LiNbO ₃ with selected SAW propagation direction. The crystal inversion asymmetry induces circularly polarized phonons with large out-of-plane angular momenta so that up to 60% of the SAW power attenuates nonreciprocally controlled by the out-of-plane magnetization component. The SAW propagation direction dependence of the nonreciprocity verifies the crystal origin of the phononic angular momentum, and a chiral spin pumping demonstrates that the circular polarization can control the spin current generation efficiency. These results provide an additional degree of freedom for the acoustic control of magnetism and open an avenue for applying circularly polarized phonons.
The 2024 magnonics roadmap

Benedetta Flebus, Dirk Grundler, Bivas Rana, YoshiChika Otani, Igor Barsukov, Anjan Barman, Gianluca Gubbiotti, Pedro Landeros, Johan Akerman, Ursula Ebels, Philipp Pirro, Vladislav E Demidov, Katrin Schultheiss, Gyorgy Csaba, Qi Wang, Florin Ciubotaru, Dmitri E Nikonov, Ping Che, Riccardo Hertel, Teruo Ono, Dmytro Afanasiev, Johan Mentink, Theo Rasing, Burkard Hillebrands, Silvia Viola Kusminskiy, Wei Zhang, Chunhui Rita Du, Aurore Finco, Toeno van der Sar, Yunqiu Kelly Luo, Yoichi Shiota, Joseph Sklenar, Tao Yu, Jinwei Rao

Journal of Physics: Condensed Matter　36　(36)　363501-363501　2024/06/14
Publisher: IOP Publishing
DOI： 10.1088/1361-648x/ad399c 　

ISSN： 0953-8984

eISSN： 1361-648X

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Abstract Magnonics is a research field that has gained an increasing interest in both the fundamental and applied sciences in recent years. This field aims to explore and functionalize collective spin excitations in magnetically ordered materials for modern information technologies, sensing applications and advanced computational schemes. Spin waves, also known as magnons, carry spin angular momenta that allow for the transmission, storage and processing of information without moving charges. In integrated circuits, magnons enable on-chip data processing at ultrahigh frequencies without the Joule heating, which currently limits clock frequencies in conventional data processors to a few GHz. Recent developments in the field indicate that functional magnonic building blocks for in-memory computation, neural networks and Ising machines are within reach. At the same time, the miniaturization of magnonic circuits advances continuously as the synergy of materials science, electrical engineering and nanotechnology allows for novel on-chip excitation and detection schemes. Such circuits can already enable magnon wavelengths of 50 nm at microwave frequencies in a 5G frequency band. Research into non-charge-based technologies is urgently needed in view of the rapid growth of machine learning and artificial intelligence applications, which consume substantial energy when implemented on conventional data processing units. In its first part, the 2024 Magnonics Roadmap provides an update on the recent developments and achievements in the field of nano-magnonics while defining its future avenues and challenges. In its second part, the Roadmap addresses the rapidly growing research endeavors on hybrid structures and magnonics-enabled quantum engineering. We anticipate that these directions will continue to attract researchers to the field and, in addition to showcasing intriguing science, will enable unprecedented functionalities that enhance the efficiency of alternative information technologies and computational schemes.
Current-driven fast magnetic octupole domain-wall motion in noncollinear antiferromagnets

Mingxing Wu, Taishi Chen, Takuya Nomoto, Yaroslav Tserkovnyak, Hironari Isshiki, Yoshinobu Nakatani, Tomoya Higo, Takahiro Tomita, Kouta Kondou, Ryotaro Arita, Satoru Nakatsuji, Yoshichika Otani

Nature Communications　15　(1)　2024/06/11
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41467-024-48440-9 　

eISSN： 2041-1723

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Abstract Antiferromagnets (AFMs) have the natural advantages of terahertz spin dynamics and negligible stray fields, thus appealing for use in domain-wall applications. However, their insensitive magneto-electric responses make controlling them in domain-wall devices challenging. Recent research on noncollinear chiral AFMs Mn₃X (X = Sn, Ge) enabled us to detect and manipulate their magnetic octupole domain states. Here, we demonstrate a current-driven fast magnetic octupole domain-wall (MODW) motion in Mn₃X. The magneto-optical Kerr observation reveals the Néel-like MODW of Mn₃Ge can be accelerated up to 750 m s^-1 with a current density of only 7.56 × 10¹⁰ A m^-2 without external magnetic fields. The MODWs show extremely high mobility with a small critical current density. We theoretically extend the spin-torque phenomenology for domain-wall dynamics from collinear to noncollinear magnetic systems. Our study opens a new route for antiferromagnetic domain-wall-based applications.
Observation of Cluster Magnetic Octupole Domains in the Antiferromagnetic Weyl Semimetal Mn3⁢Sn Nanowire

Hironari Isshiki, Nico Budai, Ayuko Kobayashi, Ryota Uesugi, Tomoya Higo, Satoru Nakatsuji, YoshiChika Otani

Physical Review Letters　132　(21)　2024/05/23
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevlett.132.216702 　

ISSN： 0031-9007

eISSN： 1079-7114
Selective Data Writing in IrMn-Based Perpendicular Magnetic Tunnel Junction Array Through Voltage-Gated Spin-Orbit Torque

Weixiang Li, Zhaochun Liu, Shouzhong Peng, Jiaqi Lu, Jiahao Liu, Xinyuan Li, Shiyang Lu, Yoshichika Otani, Weisheng Zhao

IEEE Electron Device Letters　2024/05

DOI： 10.1109/LED.2024.3369616 　
Generation of out-of-plane polarized spin current in (permalloy, Cu)/EuS interfaces

Pankhuri Gupta, Niru Chowdhury, Mingran Xu, Prasanta Kumar Muduli, Akash Kumar, Kouta Kondou, Yoshichika Otani, Pranaba Kishor Muduli

Physical Review B　109　(6)　2024/02/12
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevb.109.l060405 　

ISSN： 2469-9950

eISSN： 2469-9969
Tunable strong magnon-magnon coupling in two-dimensional array of diamond shaped ferromagnetic nanodots

Sudip Majumder, Samiran Choudhury, Saswati Barman, Yoshichika Otani, Anjan Barman

Physica Scripta　2024/02/01

DOI： 10.1088/1402-4896/ad1953 　
Strongly Coupled Spin Waves and Surface Acoustic Waves at Room Temperature

Yunyoung Hwang, Jorge Puebla, Kouta Kondou, Carlos Gonzalez-Ballestero, Hironari Isshiki, Carlos Sánchez Muñoz, Liyang Liao, Fa Chen, Wei Luo, Sadamichi Maekawa, Yoshichika Otani

Physical Review Letters　132　(5)　2024/01/31
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevlett.132.056704 　

ISSN： 0031-9007

eISSN： 1079-7114
Oxide layer dependent orbital torque efficiency in ferromagnet/Cu/oxide heterostructures

Junyeon Kim, Jun Uzuhashi, Masafumi Horio, Tomoaki Senoo, Dongwook Go, Daegeun Jo, Toshihide Sumi, Tetsuya Wada, Iwao Matsuda, Tadakatsu Ohkubo, Seiji Mitani, Hyun-Woo Lee, YoshiChika Otani

Physical Review Materials　7　(11)　2023/11/22
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevmaterials.7.l111401 　

eISSN： 2475-9953
Acoustically Driven Magnon-Phonon Coupling in a Layere Antiferromagnet Peer-reviewed

Thomas P. Lyons, Jorge Puebla, Kei Yamamoto, Russell, S. Deacon, Yunyoung Hwang, Koji Ishibashi, Sadamichi Maekawa, Yoshichika Otani

Phys. Rev. Lett.　131　196701　2023/11

DOI： 10.1103/PhysRevLett.131.196701 　
Valley-Selective Phonon-Magnon Scattering in Magnetoelastic Superlattices Peer-reviewed

Liyang Liao, Jorge Puebla, Kei Yamamoto, Junyeon Kim, Sadamichi Maekawa, Yunyoung Hwang, You Ba, Yoshichika Otani

Phys. Rev. Lett.　131　(17)　176701-1-176701-6　2023/10
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevlett.131.176701 　

ISSN： 0031-9007

eISSN： 1079-7114
Nonlinear Acoustic Spin Pumping Caused by Temperature-Dependent Frequency Shifts of Surface Acoustic Waves

Yunyoung Hwang, Jorge Puebla, Kouta Kondou, Carlos Sánchez Muñoz, Yoshichika Otani

Journal of the Physical Society of Japan　92　(9)　2023/09/15
Publisher: Physical Society of Japan
DOI： 10.7566/jpsj.92.094702 　

ISSN： 0031-9015

eISSN： 1347-4073
Magnetic octupole domain evolution and domain-wall structure in the noncollinear Weyl antiferromagnet Mn3Ge

Mingxing Wu, Kouta Kondou, Yoshinobu Nakatani, Taishi Chen, Hironari Isshiki, Tomoya Higo, Satoru Nakatsuji, Yoshichika Otani

APL Materials　11　(8)　2023/08/01
Publisher: AIP Publishing
DOI： 10.1063/5.0156191 　

eISSN： 2166-532X

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Antiferromagnets with the intrinsic advantages of terahertz spin dynamics and negligible stray fields have been extensively studied for spintronic applications. In particular, spintronic research on antiferromagnets has expanded its focus from collinear to noncollinear Weyl antiferromagnets and discovered that Mn3X (X = Sn, Ge) produces substantial magneto-electric responses. Therefore, noncollinear antiferromagnets could be an ideal spintronic platform. Exploring the domain-wall features in Mn3X is, on the other hand, essential for spintronic device engineering. Here, we report an in-depth study on magnetic octupole domain evolution and domain-wall structure with a choice of Mn3Ge single crystal. Our magneto-optical imaging and the anomalous Hall measurements elucidate the nontrivial magnetic octupole domain nucleation, domain-wall propagation, and pinning behaviors. Moreover, combining the micromagnetic simulation, we reveal that Bloch- and Néel-like walls coexist in bulk with comparable sizes and energy densities. Our findings promote understanding the magnetic octupole domain-wall physics and designing domain-wall-based spintronic devices.
Ferromagnetic resonance excited by interfacial microwave electric field: the role of current-induced torques

Angshuman Deka, Bivas Rana, YoshiChika Otani, Yasuhiro Fukuma

Journal of Physics: Condensed Matter　2023/06/02

DOI： 10.1088/1361-648X/acc377 　
Mid-infrared optical properties of non-magnetic-metal/CoFeB/MgO heterostructures

J M Flores-Camacho, Bivas Rana, R E Balderas-Navarro, A Lastras-Martínez, Yoshichika Otani, Jorge Puebla

Journal of Physics D: Applied Physics　56　(31)　315301-315301　2023/05/09
Publisher: IOP Publishing
DOI： 10.1088/1361-6463/acd00f 　

ISSN： 0022-3727

eISSN： 1361-6463

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Abstract We report on the optical characterization of non-magnetic metal (NM)/ferromagnetic (Co₂₀Fe₆₀B₂₀)/MgO heterostructures and interfaces by using mid infrared (MIR) spectroscopic ellipsometry at room temperature. We extracted for the MIR range the dielectric function (DF) of Co₂₀Fe₆₀B₂₀, that is lacking in literature, from a multisample analysis. From the optical modeling of the heterostructures we detected and determined the dielectric tensor properties of a two-dimensional electron gas (2DEG) forming at the NM and the CoFeB interface. These properties comprise independent Drude parameters for the in-plane and out-of plane tensor components, with the latter having an epsilon-near-zero frequency within our working spectral range. A feature assigned to spin–orbit coupling (SOC) is identified. Furthermore, it is found that both, the interfacial properties, 2DEG Drude parameters and SOC strength, and the apparent DF of the MgO layer depend on the type of the underlying NM, namely, Pt, W, or Cu. The results reported here should be useful in tailoring novel phenomena in such types of heterostructures by assessing their optical response noninvasively, complementing existing characterization tools such as angle-resolved photoemission spectroscopy, and those related to electron/spin transport.
Magnetic imaging by the anomalous Nernst effect using atomic force microscopy

Nico Budai, Hironari Isshiki, Ryota Uesugi, Zheng Zhu, Tomoya Higo, Satoru Nakatsuji, YoshiChika Otani

2023 IEEE International Magnetic Conference - Short Papers (INTERMAG Short Papers)　1-2　2023/05
Publisher: IEEE
DOI： 10.1109/intermagshortpapers58606.2023.10228361 　
Temperature-induced anomalous magnetotransport in the Weyl semimetal Mn₃Ge

Mingxing Wu, Kouta Kondou, Taishi Chen, Satoru Nakatsuji, Yoshichika Otani

AIP Advances　13　(4)　045102-045102　2023/04/01
Publisher: {AIP} Publishing
DOI： 10.1063/5.0138208 　

ISSN： 2158-3226

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<jats:p> The magnetic Weyl semimetallic state can lead to intriguing magnetotransport, such as chiral anomaly and the layered quantum Hall effect. Mn<jats:sub>3</jats:sub>X (X = Sn, Ge) is a noncollinear antiferromagnetic semimetal where a Weyl semimetallic state is stabilized by time-reversal symmetry breaking. Compared to the well-studied Mn<jats:sub>3</jats:sub>Sn, the Weyl fermion-induced magnetotransport in Mn<jats:sub>3</jats:sub>Ge has been merely studied. Here, we report an in-depth study on the magnetotransport in a microfabricated Mn<jats:sub>3</jats:sub>Ge single crystal from room temperature to 10 K. We reveal an anomalous anisotropic magnetoresistance with fourfold symmetry and a positive high-field longitudinal magnetoresistance below the critical temperature (160–170 K). The possible origin is the temperature-induced tilting of the Weyl nodes. Our study helps to understand the magnetotransport properties in the Weyl fermion system. </jats:p>
Bias field orientation driven reconfigurable magnonics and magnon−magnon coupling in triangular shaped Ni80Fe20 nanodot arrays

Amrit Kumar Mondal, Sudip Majumder, Bipul Kumar Mahato, Saswati Barman, Yoshichika Otani, Anjan Barman

Nanotechnology　2023/03/26

DOI： 10.1088/1361-6528/acae5e 　
High-resolution magnetic imaging by mapping the locally induced anomalous Nernst effect using atomic force microscopy

Nico Budai, Hironari Isshiki, Ryota Uesugi, Zheng Zhu, Tomoya Higo, Satoru Nakatsuji, YoshiChika Otani

APPLIED PHYSICS LETTERS　122　(10)　2023/03

DOI： 10.1063/5.0136613 　

ISSN： 0003-6951

eISSN： 1077-3118
Emerging effects of oxygen accumulation on orbital torque

Junyeon Kim, Jun Uzuhashi, Dongwook Go, Daegeun Jo, Tadakatsu Ohkubo, Seiji Mitani, Hyun-Woo Lee, YoshiChika Otani

2023/01/25

DOI： 10.21203/rs.3.rs-2451981/v1 　
Voltage Signals Caused by Surface Acoustic Wave Driven Ferromagnetic Resonance Under Out‐of‐Plane External Fields

Yunyoung Hwang, Jorge Puebla, Kouta Kondou, Yoshichika Otani

Advanced Materials Interfaces　9　(36)　2201432-2201432　2022/12
Publisher: Wiley
DOI： 10.1002/admi.202201432 　

ISSN： 2196-7350

eISSN： 2196-7350
Pattern recognition with neuromorphic computing using magnetic field-induced dynamics of skyrmions

Tomoyuki Yokouchi, Satoshi Sugimoto, Bivas Rana, Shinichiro Seki, Naoki Ogawa, Yuki Shiomi, Shinya Kasai, Yoshichika Otani

SCIENCE ADVANCES　8　(39)　2022/09

DOI： 10.1126/sciadv.abq5652 　

ISSN： 2375-2548
Determination of spin Hall angle in the Weyl ferromagnet Co2MnGa by taking into account the thermoelectric contributions

Hironari Isshiki, Zheng Zhu, Hayato Mizuno, Ryota Uesugi, Tomoya Higo, Satoru Nakatsuji, Yoshichika Otani

Physical Review Materials　6　(8)　2022/08

DOI： 10.1103/PhysRevMaterials.6.084411 　

eISSN： 2475-9953
Perpendicular full switching of chiral antiferromagnetic order by current

Tomoya Higo, Kouta Kondou, Takuya Nomoto, Masanobu Shiga, Shoya Sakamoto, Xianzhe Chen, Daisuke Nishio-Hamane, Ryotaro Arita, Yoshichika Otani, Shinji Miwa, Satoru Nakatsuji

Nature　607　(7919)　474-479　2022/07/21
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41586-022-04864-1 　

ISSN： 0028-0836

eISSN： 1476-4687
Electric field induced parametric excitation of exchange magnons in a CoFeB/MgO junction

Angshuman Deka, Bivas Rana, Ryo Anami, Katsuya Miura, Hiromasa Takahashi, Yoshichika Otani, Yasuhiro Fukuma

Physical Review Research　4　(2)　2022/06

DOI： 10.1103/PhysRevResearch.4.023139 　

ISSN： 2643-1564
Perspectives on spintronics with surface acoustic waves

J. Puebla, Y. Hwang, S. Maekawa, Y. Otani

Applied Physics Letters　2022/05/30

DOI： 10.1063/5.0093654 　
Chirality-Induced Magnetoresistance Due to Thermally Driven Spin Polarization

Kouta Kondou, Masanobu Shiga, Shoya Sakamoto, Hiroyuki Inuzuka, Atsuko Nihonyanagi, Fumito Araoka, Masaki Kobayashi, Shinji Miwa, Daigo Miyajima, YoshiChika Otani

Journal of the American Chemical Society　144　(16)　7302-7307　2022/04/27
Publisher: American Chemical Society (ACS)
DOI： 10.1021/jacs.2c00496 　

ISSN： 0002-7863

eISSN： 1520-5126
Progress in Spinconversion and its Connection with Band Crossing (Ann. Phys. 4/2022)

Jorge Puebla, Yunyoung Hwang, Kouta Kondou, Yoshichika Otani

Annalen der Physik　534　(4)　2270007-2270007　2022/04
Publisher: Wiley
DOI： 10.1002/andp.202270007 　

ISSN： 0003-3804

eISSN： 1521-3889
Progress in Spinconversion and its Connection with Band Crossing

Jorge Puebla, Yunyoung Hwang, Kouta Kondou, Yoshichika Otani

Annalen der Physik　534　(4)　2100398-2100398　2022/04
Publisher: Wiley
DOI： 10.1002/andp.202100398 　

ISSN： 0003-3804

eISSN： 1521-3889
Efficient orbital torque in polycrystalline <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mi>ferromagnetic</mml:mi><mml:mtext>−</mml:mtext><mml:mi>metal</mml:mi></mml:mrow><mml:mo>/</mml:mo><mml:mi>Ru</mml:mi><mml:mo>/</mml:mo><mml:msub><mml:mi>Al</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> stacks: Theory and experiment

Liyang Liao, Fenghua Xue, Lei Han, Junyeon Kim, Ruiqi Zhang, Lun Li, Jiuming Liu, Xufeng Kou, Cheng Song, Feng Pan, YoshiChika Otani

Physical Review B　105　(10)　2022/03/30
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevb.105.104434 　

ISSN： 2469-9950

eISSN： 2469-9969
Interaction between surface acoustic waves and spin waves in a ferromagnetic thin film

Kei Yamamoto, Mingran Xu, Jorge Puebla, Yoshichika Otani, Sadamichi Maekawa

Journal of Magnetism and Magnetic Materials　545　168672-168672　2022/03/01
Publisher: Elsevier BV
DOI： 10.1016/j.jmmm.2021.168672 　

ISSN： 0304-8853
Thickness-Dependent Reconfigurable Spin-Wave Dynamics in Ni₈₀Fe₂₀ Nanostripe Arrays

Pal, P.K., Sahoo, S., Dutta, K., Barman, A., Barman, S., Otani, Y.

Advanced Materials Interfaces　2022

DOI： 10.1002/admi.202201333 　

ISSN： 2196-7350
Efficient and controllable magnetization switching induced by intermixing-enhanced bulk spin-orbit torque in ferromagnetic multilayers

Zhang, K., Chen, L., Zhang, Y., Hong, B., He, Y., Lin, K., Zhang, Z., Zheng, Z., Feng, X., Zhang, Y., Otani, Y., Zhao, W.

Applied Physics Reviews　9　(1)　2022

DOI： 10.1063/5.0067348 　

ISSN： 1931-9401
Giant effective Zeeman splitting in a monolayer semiconductor realized by spin-selective strong light–matter coupling

Lyons, T.P., Gillard, D.J., Leblanc, C., Puebla, J., Solnyshkov, D.D., Klompmaker, L., Akimov, I.A., Louca, C., Muduli, P., Genco, A., Bayer, M., Otani, Y., Malpuech, G., Tartakovskii, A.I.

Nature Photonics　2022

DOI： 10.1038/s41566-022-01025-8 　

ISSN： 1749-4893 1749-4885
Role of Spin–Orbit Coupling on Ultrafast Spin Dynamics in Nonmagnet/Ferromagnet Heterostructures

Panda, S.N., Rana, B., Otani, Y., Barman, A.

Advanced Quantum Technologies　2022

DOI： 10.1002/qute.202200016 　

ISSN： 2511-9044
Advances in Magnetics Roadmap on Spin-Wave Computing

Chumak, A.V., Kabos, P., Wu, M., Abert, C., Adelmann, C., Adeyeye, A.O., Akerman, J., Aliev, F.G., Anane, A., Awad, A., Back, C.H., Barman, A., Bauer, G.E.W., Becherer, M., Beginin, E.N., Bittencour, V.A.S.V., Blanter, Y.M., Bortolotti, P., Boventer, I., Bozhko, D.A., Bunyaev, S.A., Carmiggelt, J.J., Cheenikundil, R.R., Ciubotaru, F., Cotofana, S., Csaba, G., Dobrovolskiy, O.V., Dubs, C., Elyasi, M., Fripp, K.G., Fulara, H., Golovchanskiy, I.A., Gonzalez-Ballestero, C., Graczyk, P., Grundler, D., Gruszecki, P., Gubbiotti, G., Guslienko, K., Haldar, A., Hamdioui, S., Hertel, R., Hillebrands, B., Hioki, T., Houshang, A., Hu, C.-M., Huebl, H., Huth, M., Iacocca, E., Jungfleisch, M.B., Kakazei, G.N., Khitun, A., Khymyn, R., Kikkawa, T., Klaui, M., Klein, O., Klos, J.W., Knauer, S., Koraltan, S., Kostylev, M., Krawczyk, M., Krivorotov, I.N., Kruglyak, V.V., Lachance-Quirion, D., Ladak, S., Lebrun, R., Li, Y., Lindner, M., MacEdo, R., Mayr, S., Melkov, G.A., Mieszczak, S., Nakamura, Y., Nembach, H.T., Nikitin, A.A., Nikitov, S.A., Novosad, V., Otalora, J.A., Otani, Y., Papp, A., Pigeau, B., Pirro, P., Porod, W., Porrati, F., Qin, H., Rana, B., Reimann, T., Riente, F., Romero-Isart, O., Ross, A., Sadovnikov, A.V., Safin, A.R., Saitoh, E., Schmidt, G., Schultheiss, H., Schultheiss, K., Serga, A.A., Sharma, S., Shaw, J.M., Suess, D., Surzhenko, O., Szulc, K., Taniguchi, T., Urbanek, M., Usami, K., Ustinov, A.B., Van Der Sar, T., Van Dijken, S., Vasyuchka, V.I., Verba, R., Kusminskiy, S.V., Wang, Q., Weides, M., Weiler, M., Wintz, S., Wolski, S.P., Zhang, X.

IEEE Transactions on Magnetics　58　(6)　2022

DOI： 10.1109/TMAG.2022.3149664 　

ISSN： 1941-0069 0018-9464
Giant field-like torque by the out-of-plane magnetic spin Hall effect in a topological antiferromagnet

Kouta Kondou, Hua Chen, Takahiro Tomita, Muhammad Ikhlas, Tomoya Higo, Allan H. MacDonald, Satoru Nakatsuji, YoshiChika Otani

Nature Communications　12　(1)　2021/12
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41467-021-26453-y 　

ISSN： 2041-1723

eISSN： 2041-1723
Observation of magnon-magnon coupling with high cooperativity in Ni80Fe20cross-shaped nanoring array

Kartik Adhikari, Samiran Choudhury, Saswati Barman, Yoshichika Otani, Anjan Barman

Nanotechnology　32　(39)　2021/09/24
Publisher: IOP Publishing Ltd
DOI： 10.1088/1361-6528/ac0ddc 　

ISSN： 1361-6528 0957-4484
Influence of planar Hall effect on the output signal in a T-shaped spin conversion device

Hayato Mizuno, Hironari Isshiki, Kouta Kondou, Yuanzhi Zhu, Yoshichika Otani

Applied Physics Letters　119　(9)　092401-092401　2021/08/30

DOI： 10.1063/5.0061147 　

ISSN： 1077-3118

eISSN： 1077-3118
Giant Effective Damping of Octupole Oscillation in an Antiferromagnetic Weyl Semimetal

Shinji Miwa, Satoshi Iihama, Takuya Nomoto, Takahiro Tomita, Tomoya Higo, Muhammad Ikhlas, Shoya Sakamoto, YoshiChika Otani, Shigemi Mizukami, Ryotaro Arita, Satoru Nakatsuji

Small Science　1　(5)　2000062-2000062　2021/05
Publisher: Wiley
DOI： 10.1002/smsc.202000062 　

ISSN： 2688-4046

eISSN： 2688-4046
Large Hall Signal due to Electrical Switching of an Antiferromagnetic Weyl Semimetal State

Hanshen Tsai, Tomoya Higo, Kouta Kondou, Shoya Sakamoto, Ayuko Kobayashi, Takumi Matsuo, Shinji Miwa, Yoshichika Otani, Satoru Nakatsuji

Small Science　1　(5)　2000025-2000025　2021/04/15
Publisher: Wiley
DOI： 10.1002/smsc.202000025 　

ISSN： 2688-4046

eISSN： 2688-4046
Spin–orbit torque switching of the antiferromagnetic state in polycrystalline Mn3Sn/Cu/heavy metal heterostructures

Hanshen Tsai, Tomoya Higo, Kouta Kondou, Ayuko Kobayashi, Takafumi Nakano, Kay Yakushiji, Shinji Miwa, Yoshichika Otani, Satoru Nakatsuji

AIP Advances　11　(4)　045110-045110　2021/04/01
Publisher: AIP Publishing
DOI： 10.1063/9.0000229 　

ISSN： 2158-3226

eISSN： 2158-3226
Omnidirectional Control of Large Electrical Output in a Topological Antiferromagnet

Tomoya Higo, Yufan Li, Kouta Kondou, Danru Qu, Muhammad Ikhlas, Ryota Uesugi, Daisuke Nishio‐Hamane, C. L. Chien, YoshiChika Otani, Satoru Nakatsuji

Advanced Functional Materials　31　(15)　2008971-2008971　2021/02/25
Publisher: Wiley
DOI： 10.1002/adfm.202008971 　

ISSN： 1616-301X

eISSN： 1616-3028
Domain structure and domain wall dynamics in topological chiral antiferromagnets from the viewpoint of magnetic octupole

YoshiChika Otani, Tomoya Higo

Applied Physics Letters　118　(4)　040501-040501　2021/01/25
Publisher: AIP Publishing
DOI： 10.1063/5.0034938 　

ISSN： 0003-6951

eISSN： 1077-3118
Nontrivial torque generation by orbital angular momentum injection in ferromagnetic-metal/ Cu/Al2O3 trilayers

Junyeon Kim, Dongwook Go, Hanshen Tsai, Daegeun Jo, Kouta Kondou, Hyun-Woo Lee, YoshiChika Otani

Physical Review B　103　(2)　2021/01/15
Publisher: American Physical Society (APS)
DOI： 10.1103/physrevb.103.l020407 　

ISSN： 2469-9950

eISSN： 2469-9969
Reconfigurable spin-wave dynamics in two-dimensional quasiperiodic magnonic crystals

Majumder, S., Choudhury, S., Barman, S., Otani, Y., Barman, A.

Physica E: Low-Dimensional Systems and Nanostructures　134　2021

DOI： 10.1016/j.physe.2021.114901 　

ISSN： 1386-9477
The 2021 Magnonics Roadmap

Barman, A., Gubbiotti, G., Ladak, S., Adeyeye, A.O., Krawczyk, M., Grafe, J., Adelmann, C., Cotofana, S., Naeemi, A., Vasyuchka, V.I., Hillebrands, B., Nikitov, S.A., Yu, H., Grundler, D., Sadovnikov, A.V., Grachev, A.A., Sheshukova, S.E., Duquesne, J.-Y., Marangolo, M., Csaba, G., Porod, W., Demidov, V.E., Urazhdin, S., Demokritov, S.O., Albisetti, E., Petti, D., Bertacco, R., Schultheiss, H., Kruglyak, V.V., Poimanov, V.D., Sahoo, S., Sinha, J., Yang, H., M{\"u}nzenberg, M., Moriyama, T., Mizukami, S., Landeros, P., Gallardo, R.A., Carlotti, G., Kim, J.-V., Stamps, R.L., Camley, R.E., Rana, B., Otani, Y., Yu, W., Yu, T., Bauer, G.E.W., Back, C., Uhrig, G.S., Dobrovolskiy, O.V., Budinska, B., Qin, H., Van Dijken, S., Chumak, A.V., Khitun, A., Nikonov, D.E., Young, I.A., Zingsem, B.W., Winklhofer, M.

Journal of Physics Condensed Matter　33　(41)　2021

DOI： 10.1088/1361-648X/abec1a 　

ISSN： 1361-648X 0953-8984
Magnonic crystals with complex geometry

De, A., Dutta, K., Mondal, S., Barman, S., Otani, Y., Barman, A.

Physical Review B　103　(6)　2021

DOI： 10.1103/PhysRevB.103.064402 　

ISSN： 2469-9969 2469-9950
Dynamic configurational anisotropy in Ni₈₀Fe₂₀ antidot lattice with complex geometry

Dutta, K., De, A., Mondal, S., Barman, S., Otani, Y., Barman, A.

Journal of Alloys and Compounds　884　2021

DOI： 10.1016/j.jallcom.2021.161105 　

ISSN： 0925-8388
Nanochannels for spin-wave manipulation in Ni₈₀Fe₂₀ nanodot arrays

Sahoo, S., Panda, S.N., Barman, S., Otani, Y., Barman, A.

Journal of Magnetism and Magnetic Materials　522　2021

DOI： 10.1016/j.jmmm.2020.167550 　

ISSN： 0304-8853
Strain-induced Megahertz Oscillation and Stable Velocity of an Antiferromagnetic Domain Wall

Chen, F., Ge, X., Luo, W., Xing, R., Liang, S., Yang, X., You, L., Xiong, R., Otani, Y., Zhang, Y.

Physical Review Applied　15　(1)　2021

DOI： 10.1103/PhysRevApplied.15.014030 　

ISSN： 2331-7019
Electrical nucleation, displacement, and detection of antiferromagnetic domain walls in the chiral antiferromagnet Mn3Sn

Satoshi Sugimoto, Yoshinobu Nakatani, Yuta Yamane, Muhammad Ikhlas, Kouta Kondou, Motoi Kimata, Takahiro Tomita, Satoru Nakatsuji, Yoshichika Otani

Communications Physics　3　(1)　2020/12
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s42005-020-0381-8 　

ISSN： 2399-3650

eISSN： 2399-3650
Spintronic devices for energy-efficient data storage and energy harvesting

Jorge Puebla, Junyeon Kim, Kouta Kondou, Yoshichika Otani

Communications Materials　1　(1)　2020/12
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s43246-020-0022-5 　

ISSN： 2662-4443

eISSN： 2662-4443
Phenomenological model for the direct and inverse Edelstein effects

Hironari Isshiki, Prasanta Muduli, Junyeon Kim, Kouta Kondou, YoshiChika Otani

Physical Review B　102　(18)　2020/11/10
Publisher: American Physical Society ({APS})
DOI： 10.1103/physrevb.102.184411 　

ISSN： 2469-9969
Chirality-induced effective magnetic field in a phthalocyanine molecule

Shinji Miwa, Kouta Kondou, Shoya Sakamoto, Atsuko Nihonyanagi, Fumito Araoka, YoshiChika Otani, Daigo Miyajima

APPLIED PHYSICS EXPRESS　13　(11)　2020/11

DOI： 10.35848/1882-0786/abbf67 　

ISSN： 1882-0778

eISSN： 1882-0786
Voltage controlled on-demand magnonic nanochannels

Samiran Choudhury, Avinash Kumar Chaurasiya, Amrit Kumar Mondal, Bivas Rana, Katsuya Miura, Hiromasa Takahashi, YoshiChika Otani, Anjan Barman

Science Advances　6　(40)　2020/10/02
Publisher: American Association for the Advancement of Science ({AAAS})
DOI： 10.1126/sciadv.aba5457 　

ISSN： 2375-2548
Emergent electromagnetic induction in a helical-spin magnet

Tomoyuki Yokouchi, Fumitaka Kagawa, Max Hirschberger, Yoshichika Otani, Naoto Nagaosa, Yoshinori Tokura

NATURE　586　(7828)　232-+　2020/10

DOI： 10.1038/s41586-020-2775-x 　

ISSN： 0028-0836

eISSN： 1476-4687
Underlayer material dependent symmetric and asymmetric behavior of voltage-controlled magnetic anisotropy in CoFeB films

Bivas Rana, Katsuya Miura, Hiromasa Takahashi, Yoshichika Otani

Journal of Physics Condensed Matter　32　(41)　414002-414002　2020/09/30
Publisher: Institute of Physics Publishing
DOI： 10.1088/1361-648X/ab99eb 　

ISSN： 1361-648X 0953-8984
Magnetic and transport properties of amorphous, B2 and L21 Co2MnGa thin films Peer-reviewed

Zheng Zhu, Tomoya Higo, Satoru Nakatsuji, YoshiChika Otani

AIP Advances　10　(8)　085020-085020　2020/08/01
Publisher: AIP Publishing
DOI： 10.1063/5.0018640 　

ISSN： 2158-3226

eISSN： 2158-3226
Nonreciprocal surface acoustic wave propagation via magneto-rotation coupling

Mingran Xu, Kei Yamamoto, Jorge Puebla, Korbinian Baumgaertl, Bivas Rana, Katsuya Miura, Hiromasa Takahashi, Dirk Grundler, Sadamichi Maekawa, Yoshichika Otani

Science Advances　6　(32)　2020/08

DOI： 10.1126/sciadv.abb1724 　

ISSN： 2375-2548

eISSN： 2375-2548
Nonreciprocal surface acoustic wave propagation via magneto-rotation coupling

Mingran Xu, Kei Yamamoto, Jorge Puebla, Korbinian Baumgaertl, Bivas Rana, Katsuya Miura, Hiromasa Takahashi, Dirk Grundler, Sadamichi Maekawa, Yoshichika Otani

SCIENCE ADVANCES　6　(32)　2020/08

DOI： 10.1126/sciadv.abb1724 　

ISSN： 2375-2548
Enhancement of acoustic spin pumping by acoustic distributed Bragg reflector cavity

Yunyoung Hwang, Jorge Puebla, Mingran Xu, Aurelien Lagarrigue, Kouta Kondou, Yoshichika Otani

Applied Physics Letters　116　(25)　2020/06/22

DOI： 10.1063/5.0011799 　

ISSN： 0003-6951
Enhancement of acoustic spin pumping by acoustic distributed Bragg reflector cavity

Yunyoung Hwang, Jorge Puebla, Mingran Xu, Aurelien Lagarrigue, Kouta Kondou, Yoshichika Otani

APPLIED PHYSICS LETTERS　116　(25)　2020/06

DOI： 10.1063/5.0011799 　

ISSN： 0003-6951

eISSN： 1077-3118
Acoustic ferromagnetic resonance and spin pumping induced by surface acoustic waves

Jorge Puebla, Mingran Xu, Bivas Rana, Kei Yamamoto, Sadamichi Maekawa, Yoshichika Otani

JOURNAL OF PHYSICS D-APPLIED PHYSICS　53　(26)　2020/06

DOI： 10.1088/1361-6463/ab7efe 　

ISSN： 0022-3727

eISSN： 1361-6463
Creation of magnetic skyrmions by surface acoustic waves

Tomoyuki Yokouchi, Satoshi Sugimoto, Bivas Rana, Shinichiro Seki, Naoki Ogawa, Shinya Kasai, Yoshichika Otani

Nature Nanotechnology　15　(5)　361-366　2020/05/01
Publisher: Nature Research
DOI： 10.1038/s41565-020-0661-1 　

ISSN： 1748-3395 1748-3387
Electrical manipulation of a topological antiferromagnetic state Peer-reviewed

Hanshen Tsai, Tomoya Higo, Kouta Kondou, Takuya Nomoto, Akito Sakai, Ayuko Kobayashi, Takafumi Nakano, Kay Yakushiji, Ryotaro Arita, Shinji Miwa, Yoshichika Otani, Satoru Nakatsuji

Nature　580　(7805)　608-613　2020/04/20
Publisher: Springer Science and Business Media {LLC}
DOI： 10.1038/s41586-020-2211-2 　

ISSN： 1476-4687 0028-0836
Acoustic ferromagnetic resonance and spin pumping induced by surface acoustic waves

Jorge Puebla, Mingran Xu, Bivas Rana, Kei Yamamoto, Sadamichi Maekawa, Yoshichika Otani

Journal of Physics D: Applied Physics　53　(26)　2020/04

DOI： 10.1088/1361-6463/ab7efe 　

ISSN： 0022-3727

eISSN： 1361-6463
Magneto-optical Kerr effect in a non-collinear antiferromagnet Mn3Ge

Mingxing Wu, Hironari Isshiki, Taishi Chen, Tomoya Higo, Satoru Nakatsuji, YoshiChika Otani

APPLIED PHYSICS LETTERS　116　(13)　2020/03

DOI： 10.1063/1.5143959 　

ISSN： 0003-6951

eISSN： 1077-3118
Evidence for spin swapping from modulation of transverse resistance in magnetic heterostructures with Rashba interface Peer-reviewed

Heeman Kim, Shutaro Karube, Juan Borge, Junyeon Kim, Kouta Kondou, YoshiChika Otani

APPLIED PHYSICS LETTERS　116　(12)　2020/03

DOI： 10.1063/1.5143955 　

ISSN： 0003-6951

eISSN： 1077-3118
Effect of sample size on anomalous Nernst effect in chiral antiferromagnetic Mn3Sn devices

Hideki Narita, Tomoya Higo, Muhammad Ikhlas, Satoru Nakatsuji, YoshiChika Otani

Applied Physics Letters　116　(7)　2020/02/18
Publisher: American Institute of Physics Inc.
DOI： 10.1063/1.5126615 　

ISSN： 0003-6951
Large nonlinear ferromagnetic resonance shift and strong magnon-magnon coupling in N i80 F e20 nanocross array

Adhikari, K., Sahoo, S., Mondal, A.K., Otani, Y., Barman, A.

Physical Review B　101　(5)　2020

DOI： 10.1103/PhysRevB.101.054406 　

ISSN： 2469-9969 2469-9950
Propagation dynamics of spin excitations along skyrmion strings

Seki, S., Garst, M., Waizner, J., Takagi, R., Khanh, N.D., Okamura, Y., Kondou, K., Kagawa, F., Otani, Y., Tokura, Y.

Nature Communications　11　(1)　2020

DOI： 10.1038/s41467-019-14095-0 　

ISSN： 2041-1723
Phase boundary exchange coupling in the mixed magnetic phase regime of a Pd-doped FeRh epilayer

Massey, J.R., Matsumoto, K., Strungaru, M., Temple, R.C., Higo, T., Kondou, K., Evans, R.F.L., Burnell, G., Chantrell, R.W., Otani, Y., Marrows, C.H.

Physical Review Materials　4　(2)　2020

DOI： 10.1103/PhysRevMaterials.4.024403 　

ISSN： 2475-9953
Electric-field control of interfacial in-plane magnetic anisotropy in CoFeB/MgO junctions

Deka, A., Rana, B., Anami, R., Miura, K., Takahashi, H., Otani, Y., Fukuma, Y.

Physical Review B　101　(17)　2020

DOI： 10.1103/PhysRevB.101.174405 　

ISSN： 2469-9969 2469-9950
Nonlinear Control of Damping Constant by Electric Field in Ultrathin Ferromagnetic Films

Rana, B., Akosa, C.A., Miura, K., Takahashi, H., Tatara, G., Otani, Y.

Physical Review Applied　14　(1)　2020

DOI： 10.1103/PhysRevApplied.14.014037 　

ISSN： 2331-7019
Structural and magnetic properties of Mn<inf>3</inf>Ge films with Pt and Ru seed layers Peer-reviewed

A. Kobayashi, T. Higo, S. Nakatsuji, Yoshichika Otani

AIP Advances　10　(1)　2020/01/01

DOI： 10.1063/1.5130522 　

ISSN： 2158-3226

eISSN： 2158-3226
Two-dimensional electron gas in a metal/amorphous oxide interface with spin-orbit interaction

Jose Manuel Flores-Camacho, Jorge Puebla, Florent Auvray, Alfonso Lastras-Martínez, Yoshichika Otani, Raul Eduardo Balderas-Navarro

Physical Review B　100　(23)　2019/12/24

DOI： 10.1103/PhysRevB.100.235449 　

ISSN： 2469-9950

eISSN： 2469-9969
Two-dimensional electron gas in a metal/amorphous oxide interface with spin-orbit interaction

Jose Manuel Flores-Camacho, Jorge Puebla, Florent Auvray, Alfonso Lastras-Martinez, Yoshichika Otani, Raul Eduardo Balderas-Navarro

PHYSICAL REVIEW B　100　(23)　2019/12

DOI： 10.1103/PhysRevB.100.235449 　

ISSN： 2469-9950

eISSN： 2469-9969
Photoinduced Rashba Spin-to-Charge Conversion via an Interfacial Unoccupied State. International-journal

Jorge Puebla, Florent Auvray, Naoya Yamaguchi, Mingran Xu, Satria Zulkarnaen Bisri, Yoshihiro Iwasa, Fumiyuki Ishii, Yoshichika Otani

Physical review letters　122　(25)　256401-256401　2019/06/28

DOI： 10.1103/PhysRevLett.122.256401 　

ISSN： 1079-7114 0031-9007
Evaluation of spin diffusion length and spin Hall angle of the antiferromagnetic Weyl semimetal Mn3Sn Peer-reviewed

P. K. Muduli, T. Higo, T. Nishikawa, D. Qu, H. Isshiki, K. Kondou, D. Nishio-Hamane, S. Nakatsuji, Yoshichika Otani

Physical Review B　99　(18)　2019/05/20

DOI： 10.1103/PhysRevB.99.184425 　

ISSN： 2469-9950

eISSN： 2469-9969
Magnetic and magnetic inverse spin Hall effects in a non-collinear antiferromagnet (vol 565, pg 627, 2019) Peer-reviewed

Kimata Motoi, Chen Hua, Kondou Kouta, Sugimoto Satoshi, Muduli Prasanta K, Ikhlas Muhammad, Omori Yasutomo, Tomita Takahiro, MacDonald Allan. H, Nakatsuji Satoru, Otani Yoshichika

NATURE　566　(7742)　E4　2019/02/07

DOI： 10.1038/s41586-019-0907-y 　

ISSN： 0028-0836
Magnetic and magnetic inverse spin Hall effects in a non-collinear antiferromagnet Peer-reviewed

Kimata Motoi, Chen Hua, Kondou Kouta, Sugimoto Satoshi, Muduli Prasanta K, Ikhlas Muhammad, Omori Yasutomo, Tomita Takahiro, MacDonald Allan H, Nakatsuji Satoru, Otani Yoshichika

NATURE　565　(7741)　627-+　2019/01/31

DOI： 10.1038/s41586-018-0853-0 　

ISSN： 0028-0836
Relation between spin Hall effect and anomalous Hall effect in 3d ferromagnetic metals Peer-reviewed

Yasutomo Omori, Edurne Sagasta, Yasuhiro Niimi, Martin Gradhand, Luis E. Hueso, Fèlix Casanova, YoshiChika Otani

Physical Review B　99　(1)　014403-014403　2019/01/03

DOI： 10.1103/physrevb.99.014403 　

ISSN： 2469-9950

eISSN： 2469-9969
Shape dependent high frequency spin-wave dynamics in nanoscale magnonic crystals

De, A., Mondal, S., Choudhury, S., Sahoo, S., Majumder, S., Barman, S., Otani, Y., Barman, A.

Journal of Magnetism and Magnetic Materials　487　2019

DOI： 10.1016/j.jmmm.2019.165263 　

ISSN： 0304-8853
Nonlocal Spin Valves in Metallic Nanostructures

Yoshichika Otani

SPINTRONICS HANDBOOK: SPIN TRANSPORT AND MAGNETISM: NANOSCALE SPINTRONICS AND APPLICATIONS, VOL 3, EDITION　2019
Electric field control of spin waves in ultrathin CoFeB films

Rana, B., Choudhury, S., Miura, K., Takahashi, H., Barman, A., Otani, Y.

Physical Review B　100　(22)　2019

DOI： 10.1103/PhysRevB.100.224412 　

ISSN： 2469-9969 2469-9950
Controlled evolution of spin waves in unconventional defective honeycomb antidot lattices

Choudhury, S., Barman, S., Otani, Y., Barman, A.

Journal of Magnetism and Magnetic Materials　489　2019

DOI： 10.1016/j.jmmm.2019.165408 　

ISSN： 0304-8853
Interfacial mechanism in the anomalous Hall effect of Co/Bi2 O3 bilayers

Sagasta, E., Borge, J., Esteban, L., Omori, Y., Gradhand, M., Otani, Y., Hueso, L.E., Casanova, F.

Physical Review B　100　(10)　2019

DOI： 10.1103/PhysRevB.100.100407 　

ISSN： 2469-9969 2469-9950
Anisotropic spin-wave dispersion in two-dimensional Ni₈₀Fe₂₀ diatomic nanodot array

De, A., Banerjee, C., Kumar Chaurasiya, A., Mandal, R., Otani, Y., Kumar Mitra, R., Barman, A.

Journal of Magnetism and Magnetic Materials　491　2019

DOI： 10.1016/j.jmmm.2019.165557 　

ISSN： 0304-8853
Anisotropic spin waves in two-dimensional triangular shaped bi-component magnonic crystal

Choudhury, S., Pan, S., Barman, S., Otani, Y., Barman, A.

Journal of Magnetism and Magnetic Materials　490　2019

DOI： 10.1016/j.jmmm.2019.165484 　

ISSN： 0304-8853
Enhanced spin-to-charge current conversion at metal/oxide interfaces by lowering the temperature

Hanshen Tsai, Kouta Kondou, Yoshichika Otani

Japanese Journal of Applied Physics　58　(11)　2019
Publisher: Institute of Physics Publishing
DOI： 10.7567/1347-4065/ab4c15 　

ISSN： 1347-4065 0021-4922
Realization of spin dependent functionality by covering a metal surface with a single layer of molecules

Isshiki H., Kondou K., Takizawa S., Shimose K., Kawabe T., Minamitani E., Yamaguchi N., Ishii F., Shiotari A., Sugimoto Y., Miwa S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　74.2　(10)　865-865　2019
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.74.2.0_865 　

ISSN： 1530-6992 1530-6984

eISSN： 2189-0803
Clear variation of spin splitting by changing electron distribution at non-magnetic metal/Bi2O3 interfaces

Hanshen Tsai, Shutaro Karube, Kouta Kondou, Naoya Yamaguchi, Fumiyuki Ishii, Yoshichika Otani

Scientific Reports　8　(1)　2018/12
Publisher: Springer Science and Business Media LLC
DOI： 10.1038/s41598-018-23787-4 　

ISSN： 2045-2322

eISSN： 2045-2322
Anomalous Hall effect in thin films of the Weyl antiferromagnet Mn<inf>3</inf>Sn Peer-reviewed

Tomoya Higo, Danru Qu, Yufan Li, C. L. Chien, Yoshichika Otani, Satoru Nakatsuji

Applied Physics Letters　113　(20)　2018/11/12

DOI： 10.1063/1.5064697 　

ISSN： 0003-6951
Efficient spin current generation and suppression of magnetic damping due to fast spin ejection from nonmagnetic metal/indium-tin-oxide interfaces Peer-reviewed

Kondou Kouta, Tsai Hanshen, Isshiki Hironari, Otani YoshiChika

APL MATERIALS　6　(10)　2018/10

DOI： 10.1063/1.5050848 　

ISSN： 2166-532X
Spin accumulation at nonmagnetic interface induced by direct Rashba–Edelstein effect

Florent Auvray, Jorge Puebla, Mingran Xu, Bivas Rana, Daisuke Hashizume, Yoshichika Otani

Journal of Materials Science: Materials in Electronics　29　(18)　15664-15670　2018/09/01

DOI： 10.1007/s10854-018-9162-5 　

ISSN： 0957-4522

eISSN： 1573-482X
Spin accumulation at nonmagnetic interface induced by direct Rashba-Edelstein effect

Florent Auvray, Jorge Puebla, Mingran Xu, Bivas Rana, Daisuke Hashizume, Yoshichika Otani

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS　29　(18)　15664-15670　2018/09

DOI： 10.1007/s10854-018-9162-5 　

ISSN： 0957-4522

eISSN： 1573-482X
Detection of the interfacial exchange field at a ferromagnetic insulator-nonmagnetic metal interface with pure spin currents Peer-reviewed

Muduli P. K, Kimata M, Omori Y, Wakamura T, Dash Saroj P, Otani YoshiChika

PHYSICAL REVIEW B　98　(2)　2018/07/17

DOI： 10.1103/PhysRevB.98.024416 　

ISSN： 2469-9950

eISSN： 2469-9969
Direct current modulation of spin-Hall-induced spin torque ferromagnetic resonance in platinum/permalloy bilayer thin films Peer-reviewed

Shigeyuki Hirayama, Seiji Mitani, Yoshichika Otani, Shinya Kasai

Japanese Journal of Applied Physics　57　(6)　2018/06/01
Publisher: Japan Society of Applied Physics
DOI： 10.7567/JJAP.57.060301 　

ISSN： 1347-4065 0021-4922
Inverse Edelstein effect induced by magnon-phonon coupling

Mingran Xu, Jorge Puebla, Florent Auvray, Bivas Rana, Kouta Kondou, Yoshichika Otani

Physical Review B　97　(18)　2018/05/10

DOI： 10.1103/PhysRevB.97.180301 　

ISSN： 2469-9950

eISSN： 2469-9969
Inverse Edelstein effect induced by magnon-phonon coupling

Mingran Xu, Jorge Puebla, Florent Auvray, Bivas Rana, Kouta Kondou, Yoshichika Otani

PHYSICAL REVIEW B　97　(18)　2018/05

DOI： 10.1103/PhysRevB.97.180301 　

ISSN： 2469-9950

eISSN： 2469-9969
Macroscopic Magnetization Control by Symmetry Breaking of Photoinduced Spin Reorientation with Intense Terahertz Magnetic Near Field Peer-reviewed

Takayuki Kurihara, Hiroshi Watanabe, Makoto Nakajima, Shutaro Karube, Kenichi Oto, YoshiChika Otani, Tohru Suemoto

Physical Review Letters　120　(10)　2018/03/09

DOI： 10.1103/PhysRevLett.120.107202 　

ISSN： 1079-7114 0031-9007

eISSN： 1079-7114
Voltage-Controlled Reconfigurable Spin-Wave Nanochannels and Logic Devices

Rana, B., Otani, Y.

Physical Review Applied　9　(1)　2018

DOI： 10.1103/PhysRevApplied.9.014033 　

ISSN： 2331-7019
Unveiling the mechanisms of the spin Hall effect in Ta

Sagasta, E., Omori, Y., V{\'e}lez, S., Llopis, R., Tollan, C., Chuvilin, A., Hueso, L.E., Gradhand, M., Otani, Y., Casanova, F.

Physical Review B　98　(6)　2018

DOI： 10.1103/PhysRevB.98.060410 　

ISSN： 2469-9969 2469-9950
Quantum materials for spin and charge conversion

Han, W., Otani, Y., Maekawa, S.

npj Quantum Materials　3　(1)　2018

DOI： 10.1038/s41535-018-0100-9 　

ISSN： 2397-4648
Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

De, A., Mondal, S., Sahoo, S., Barman, S., Otani, Y., Mitra, R.K., Barman, A.

Beilstein Journal of Nanotechnology　9　(1)　2018

DOI： 10.3762/bjnano.9.104 　

ISSN： 2190-4286
Influence of anisotropic dipolar interaction on the spin dynamics of Ni₈₀Fe₂₀ nanodot arrays arranged in honeycomb and octagonal lattices

Mondal, S., Barman, S., Choudhury, S., Otani, Y., Barman, A.

Journal of Magnetism and Magnetic Materials　458　2018

DOI： 10.1016/j.jmmm.2018.03.003 　

ISSN： 0304-8853
Large enhancement of the spin Hall effect in Mn metal by Sn doping

Qu, D., Higo, T., Nishikawa, T., Matsumoto, K., Kondou, K., Nishio-Hamane, D., Ishii, R., Muduli, P.K., Otani, Y., Nakatsuji, S.

Physical Review Materials　2　(10)　2018

DOI： 10.1103/PhysRevMaterials.2.102001 　

ISSN： 2475-9953
Tunable Angle-Dependent Magnetization Dynamics in Ni80Fe20 Nanocross Structures of Varying Size

Adhikari, K., Barman, S., Mandal, R., Otani, Y., Barman, A.

Physical Review Applied　10　(4)　2018

DOI： 10.1103/PhysRevApplied.10.044010 　

ISSN： 2331-7019
Magnetothermodynamic properties and anomalous magnetic phase transition in FeRh nanowires

Matsumoto, K., Kimata, M., Kondou, K., Temple, R.C., Marrows, C.H., Otani, Y.

IEEE Transactions on Magnetics　54　(11)　2018

DOI： 10.1109/TMAG.2018.2832191 　

ISSN： 0018-9464
Spin Relaxation Enhanced by Decorating Cu Surfaces with Lead (II) Phthalocyanine Molecules

Takizawa, S., Kondou, K., Isshiki, H., Shimose, K., Kawabe, T., Miwa, S., Otani, Y.

IEEE Transactions on Magnetics　54　(11)　2018

DOI： 10.1109/TMAG.2018.2846364 　

ISSN： 0018-9464
Active Control of Mode Crossover and Mode Hopping of Spin Waves in a Ferromagnetic Antidot Lattice

Choudhury, S., Majumder, S., Barman, S., Otani, Y., Barman, A.

Physical Review Applied　10　(6)　2018

DOI： 10.1103/PhysRevApplied.10.064044 　

ISSN： 2331-7019
Anomalous modulation of spin torque-induced ferromagnetic resonance caused by direct currents in permalloy/platinum bilayer thin films Peer-reviewed

Shigeyuki Hirayama, Seiji Mitani, YoshiChika Otani, Shinya Kasai

APPLIED PHYSICS EXPRESS　11　(1)　2018/01

DOI： 10.7567/APEX.11.013002 　

ISSN： 1882-0778

eISSN： 1882-0786
Large anomalous Nernst effect at room temperature in a chiral antiferromagnet

Muhammad Ikhlas, Takahiro Tomita, Takashi Koretsune, Michi-To Suzuki, Daisuke Nishio-Hamane, Ryotaro Arita, Yoshichika Otani, Satoru Nakatsuji

NATURE PHYSICS　13　(11)　1085-+　2017/11

DOI： 10.1038/NPHYS4181 　

ISSN： 1745-2473

eISSN： 1745-2481
Anomalous Nernst effect in a microfabricated thermoelectric element made of chiral antiferromagnet Mn3Sn Peer-reviewed

Hideki Narita, Muhammad Ikhlas, Motoi Kimata, Agustinus Agung Nugroho, Satoru Nakatsuji, YoshiChika Otani

APPLIED PHYSICS LETTERS　111　(20)　1-5　2017/11

DOI： 10.1063/1.5000815 　

ISSN： 0003-6951

eISSN： 1077-3118
Evaluation of bulk-interface contributions to Edelstein magnetoresistance at metal/oxide interfaces Peer-reviewed

Junyeon Kim, Yan-Ting Chen, Shutaro Karube, Saburo Takahashi, Kouta Kondou, Gen Tatara, YoshiChika Otani

PHYSICAL REVIEW B　96　(14)　2017/10

DOI： 10.1103/PhysRevB.96.140409 　

ISSN： 2469-9950

eISSN： 2469-9969
Investigation of magnetization dynamics in 2D Ni80Fe20 diatomic nanodot arrays Peer-reviewed

Anulekha De, Sucheta Mondal, Chandrima Banerjee, Avinash K. Chaurasiya, Ruma Mandal, Yoshichika Otani, Rajib K. Mitra, Anjan Barman

JOURNAL OF PHYSICS D-APPLIED PHYSICS　50　(38)　2017/09

DOI： 10.1088/1361-6463/aa7ec7 　

ISSN： 0022-3727

eISSN： 1361-6463
Spin conversion on the nanoscale Peer-reviewed

YoshiChika Otani, Masashi Shiraishi, Akira Oiwa, Eiji Saitoh, Shuichi Murakami

NATURE PHYSICS　13　(9)　829-832　2017/09

DOI： 10.1038/NPHYS4192 　

ISSN： 1745-2473

eISSN： 1745-2481
Direct optical observation of spin accumulation at nonmagnetic metal/oxide interface

Jorge Puebla, Florent Auvray, Mingran Xu, Bivas Rana, Antoine Albouy, Hanshen Tsai, Kouta Kondou, Gen Tatara, Yoshichika Otani

Applied Physics Letters　111　(9)　2017/08/28

DOI： 10.1063/1.4990113 　

ISSN： 0003-6951
Spin diffusion length of Permalloy using spin absorption in lateral spin valves

Edurne Sagasta, Yasutomo Omori, Miren Isasa, Yoshichika Otani, Luis E. Hueso, Fèlix Casanova

Applied Physics Letters　111　(8)　2017/08/21
Publisher: American Institute of Physics Inc.
DOI： 10.1063/1.4990652 　

ISSN： 0003-6951
Direct optical observation of spin accumulation at nonmagnetic metal/oxide interface

Jorge Puebla, Florent Auvray, Mingran Xu, Bivas Rana, Antoine Albouy, Hanshen Tsai, Kouta Kondou, Gen Tatara, Yoshichika Otani

APPLIED PHYSICS LETTERS　111　(9)　2017/08

DOI： 10.1063/1.4990113 　

ISSN： 0003-6951

eISSN： 1077-3118
Spin pumping due to spin waves in magnetic vortex structure

Hasegawa Norinobu, Kondou Kouta, Kimata Motoi, Otani YoshiChika

Appl. Phys. Express　10　(5)　53002-53002　2017/04/27
Publisher: Institute of Physics
DOI： 10.7567/APEX.10.053002 　

ISSN： 1882-0778
Spin Conversion Phenomena in Spintronics

Yoshichika Otani

IEEE Transactions on Magnetics　2017
Efficient Modulation of Spin Waves in Two-Dimensional Octagonal Magnonic Crystal

Choudhury, S., Barman, S., Otani, Y., Barman, A.

ACS Nano　11　(9)　2017

DOI： 10.1021/acsnano.7b02872 　

ISSN： 1936-086X 1936-0851
Current-Nonlinear Hall Effect and Spin-Orbit Torque Magnetization Switching in a Magnetic Topological Insulator

Yasuda, K., Tsukazaki, A., Yoshimi, R., Kondou, K., Takahashi, K.S., Otani, Y., Kawasaki, M., Tokura, Y.

Physical Review Letters　119　(13)　2017

DOI： 10.1103/PhysRevLett.119.137204 　

ISSN： 1079-7114 0031-9007
The dynamics of magnetic vortices and skyrmions

Antos, R., Otani, Y.

Spin Current　2017

DOI： 10.1093/oso/9780198787075.003.0022 　
Magnetization switching due to nonlocal spin injection

Kimura, T., Otani, Y.

Spin Current　2017

DOI： 10.1093/oso/9780198787075.003.0021 　
Bias field tunable magnetic configuration and magnetization dynamics in Ni₈₀Fe₂₀ nano-cross structures with varying arm length

Adhikari, K., Choudhury, S., Mandal, R., Barman, S., Otani, Y., Barman, A.

Journal of Applied Physics　121　(4)　2017

DOI： 10.1063/1.4974886 　

ISSN： 1089-7550 0021-8979
Effect of Magnetic Fluctuations on Spin Current Peer-reviewed

Yasuhiro Niimi, Dahai Wei, YoshiChika Otani

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　86　(1)　011004-011004　2017/01

DOI： 10.7566/JPSJ.86.011004 　

ISSN： 0031-9015
High output voltage of magnetic tunnel junctions with a Cu(In0.8Ga0.2)Se-2 semiconducting barrier with a low resistance-area product Peer-reviewed

Koki Mukaiyama, Shinya Kasai, Yukiko K. Takahashi, Kouta Kondou, Yoshichika Otani, Seiji Mitani, Kazuhiro Hono

APPLIED PHYSICS EXPRESS　10　(1)　2017/01

DOI： 10.7567/APEX.10.013008 　

ISSN： 1882-0778

eISSN： 1882-0786
Important role of magnetization precession angle measurement in inverse spin Hall effect induced by spin pumping Peer-reviewed

Surbhi Gupta, Rohit Medwal, Daichi Kodama, Kouta Kondou, YoshiChika Otani, Yasuhiro Fukuma

APPLIED PHYSICS LETTERS　110　(2)　2017/01

DOI： 10.1063/1.4973704 　

ISSN： 0003-6951

eISSN： 1077-3118
Tuning the spin Hall effect of Pt from the moderately dirty to the superclean regime Peer-reviewed

Edurne Sagasta, Yasutomo Omori, Miren Isasa, Martin Gradhand, Luis E. Hueso, Yasuhiro Niimi, YoshiChika Otani, Felix Casanova

PHYSICAL REVIEW B　94　(6)　060412(R)-060412(R)　2016/08

DOI： 10.1103/PhysRevB.94.060412 　

ISSN： 2469-9950

eISSN： 2469-9969
Spin mixing conductance in Cu–Ir dilute alloys

Takizawa Sei, Kimata Motoi, Omori Yasutomo, Niimi Yasuhiro, Otani YoshiChika

Appl. Phys. Express　9　(6)　63009-63009　2016/05/20
Publisher: Institute of Physics
DOI： 10.7567/APEX.9.063009 　

ISSN： 1882-0778
Experimental observation of spin-to-charge current conversion at non-magnetic metal/Bi2O3 interfaces Peer-reviewed

Shutaro Karube, Kouta Kondou, YoshiChika Otani

APPLIED PHYSICS EXPRESS　9　(3)　2016/03

DOI： 10.7567/APEX.9.033001 　

ISSN： 1882-0778

eISSN： 1882-0786
Influence of inverse spin Hall effect in spin-torque ferromagnetic resonance measurements Peer-reviewed

Kouta Kondou, Hiroaki Sukegawa, Shinya Kasai, Seiji Mitani, Yasuhiro Niimi, YoshiChika Otani

APPLIED PHYSICS EXPRESS　9　(2)　2016/02

DOI： 10.7567/APEX.9.023002 　

ISSN： 1882-0778

eISSN： 1882-0786
21pBH-5 Mechanism of domain creation at the initial process of THz-induced spin reorientation phase transition in ErFeO_3

Kurihara T., Watanabe H., Karube S., Oto K., Otani Y., Nakajima M., Suemoto T.

Meeting Abstracts of the Physical Society of Japan　71　1540-1540　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1540 　

ISSN： 2189-079X
Transition from strongly collective to completely isolated ultrafast magnetization dynamics in two-dimensional hexagonal arrays of nanodots with varying inter-dot separation

Mondal, S., Choudhury, S., Barman, S., Otani, Y., Barman, A.

RSC Advances　6　(111)　2016

DOI： 10.1039/c6ra21028g 　

ISSN： 2046-2069
Observation of anisotropic energy transfer in magnetically coupled magnetic vortex pair

Hasegawa, N., Sugimoto, S., Kumar, D., Barman, S., Barman, A., Kondou, K., Otani, Y.

Applied Physics Letters　108　(24)　2016

DOI： 10.1063/1.4953600 　

ISSN： 0003-6951
Large magnetoresistance in Heusler-alloy-based epitaxial magnetic junctions with semiconducting Cu(In_0.8Ga_0.2)Se₂ spacer

Kasai, S., Takahashi, Y.K., Cheng, P.-H., Ikhtiar, Ohkubo, T., Kondou, K., Otani, Y., Mitani, S., Hono, K.

Applied Physics Letters　109　(3)　2016

DOI： 10.1063/1.4959144 　

ISSN： 0003-6951
Optimization of spin injection and spin detection in lateral nanostructures by geometrical means

Stejskal, O., Hamrle, J., Pi?tora, J., Otani, Y.

Journal of Magnetism and Magnetic Materials　414　2016

DOI： 10.1016/j.jmmm.2016.04.051 　

ISSN： 0304-8853
Magnetochiral nonreciprocity of volume spin wave propagation in chiral-lattice ferromagnets

Seki, S., Okamura, Y., Kondou, K., Shibata, K., Kubota, M., Takagi, R., Kagawa, F., Kawasaki, M., Tatara, G., Otani, Y., Tokura, Y.

Physical Review B　93　(23)　2016

DOI： 10.1103/PhysRevB.93.235131 　

ISSN： 2469-9969 2469-9950
Spin-current-driven thermoelectric generation based on interfacial spin-orbit coupling

Yagmur, A., Karube, S., Uchida, K., Kondou, K., Iguchi, R., Kikkawa, T., Otani, Y., Saitoh, E.

Applied Physics Letters　108　(24)　2016

DOI： 10.1063/1.4953879 　

ISSN： 0003-6951
Shape- and Interface-Induced Control of Spin Dynamics of Two-Dimensional Bicomponent Magnonic Crystals

Choudhury, S., Saha, S., Mandal, R., Barman, S., Otani, Y., Barman, A.

ACS Applied Materials and Interfaces　8　(28)　2016

DOI： 10.1021/acsami.6b04011 　

ISSN： 1944-8252 1944-8244
Fermi-level-dependent charge-to-spin current conversion by Dirac surface states of topological insulators

Kondou, K., Yoshimi, R., Tsukazaki, A., Fukuma, Y., Matsuno, J., Takahashi, K.S., Kawasaki, M., Tokura, Y., Otani, Y.

Nature Physics　12　(11)　2016

DOI： 10.1038/nphys3833 　

ISSN： 1745-2481 1745-2473
Anomalous Hall Effect in Chiral Antiferromagnet Mn₃Sn under Rotating Magnetic Field

Tomita Takahiro, Muhammad Ikhlas, Nishikawa Takashi, Nakatsuji Satoru, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　990-990　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_990 　
19pPSB-24 Spin mixing conductance in CuIr dilute alloys

Takizawa S., Kimata M., Niimi Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　1150-1150　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1150 　

ISSN： 2189-079X
19pPSB-21 Fabrication of spin injection device using bulk single crystals

Kimata M., Uchida Y., Omori Y., Kiyohara N., Ikhlas Muhammad, Nakatsuji S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　1147-1147　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1147 　

ISSN： 2189-079X
Anomalous Nernst effect in a chiral antiferromagnet

Narita H., Kikkawa T., Ikhlas M., Kimata M., Uchida K., Saitoh E., Nakatsuji S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　725-725　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_725 　
19pPSB-32 Size effect in electrical transport properties of a frustrated antiferromagnet NiS_2

Uchida Y., Kimata M., Higo T., Nakatsuji S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　1158-1158　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1158 　

ISSN： 2189-079X
19pPSB-25 Electrical transport properties and magnetic structures of micro fabricated FeRh film

Matsumoto K., Kimata M., Taniuchi T., Shin S., Temple R., Marrows C. H., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　1151-1151　2016
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1151 　

ISSN： 2189-079X
Magnetoresistance induced by Edelstein effect at Bi2O3/Cu interface

Kim Junyeon, Karube Shutaro, Chen Yan-Ting, Kondou Kouta, Tatara Gen, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　917-917　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_917 　

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Here we report novel Edelstein effect (EE) magnetoresistance (MR) in CoFe/Cu/BiO trilayer system. Spin current originated from the EE in Cu/BiO interface is transferred to CoFe layer dependent on its magnetization direction. This process leads the novel MR.
Electric spin injection to conductive organic thin film

Takizawa Sei, Omori Yasutomo, Kimata Motoi, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　884-884　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_884 　
Materials dependence of spin-to-charge current conversion at non-magnetic metal/Bi₂O₃ interface

Tsai Hanshen, Kondo Kouta, Karube Shutaro, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　885-885　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_885 　

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In this study, we demonstrate the spin-to-charge current conversion of non-magnetic metal/Bi_2_O_3_ interface by means of spin pumping. In addition, the materials dependence of conversion efficiency at NM/Bi_2_O_3_ interface is discussed. Three different trilayer samples, Py/Cu/Bi_2_O_3_, Py/Ag/Bi_2_O_3_, and Py/Au/Bi_2_O_3_, are prepared. In the experiment, a spin current generated by spin pumping from permalloy converses to charge current at the NM/Bi_2_O_3_ interface and then the signal voltage is detected.
Anomalous-Hall-effect induced spin accumulation in a chiral antiferromagnet Mn₃Sn

Kimata Motoi, Omori Yasutomo, Yoshida Taku, Uchida Yusuke, Ikhlas Muhammad, Kiyohara Naoki, Nakatsuji Satoru, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　912-912　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_912 　
Large Anomalous Nernst Effect in Non-collinear Antiferromagnets Mn₃Z (Z=Sn, Ge)

Ikhlas Muhammad, Tomita Takahiro, Nakatsuji Satoru, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　991-991　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_991 　

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The Anomalous Nernst Effect (ANE) is the conversion of heat flow into spontaneous transverse electricity and has been considered to be proportional to the magnetization, hence it has only been observed in ferromagnets. We report the observation of a large ANE at zero field in the non-collinear antiferromagnet Mn3Z (Z=Sn, Ge). While it only carries a very small magnetization ranging from 0.003 μB/Mn - 0.02 μB/Mn and , the transverse Seebeck coefficient is - 0.5 μV/K at room temperature and reaches - 1 μV/K at 200 K, comparable to those observed in ordinary ferromagnets. We will also discuss the effect of Ga doping into the Z-site.
Growth and Physical properties of Pd-doped FeRh films

Matsumoto K., Kimata M., Temple R. C., Marrows C. H., Taniuchi T., Shin S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　71　982-982　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_982 　
Current control of magnetic domain walls in the micro-sized single crystal of Cd₂Os₂O₇

Hirose Hishiro T., Kimata Motoi, Uchida Yusuke, Otani Yoshichika, Hiroi Zenji

Meeting Abstracts of the Physical Society of Japan　71　1976-1976　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_1976 　
Size effect in electrical transport properties with microfabrication of antiferromagnet NiS₂

Uchida Yusuke, Kimata Motoi, Higo Tomoya, Nakatsuji Satoru, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　71　726-726　2016
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.71.2.0_726 　
Reciprocal spin Hall effects in conductors with strong spin-orbit coupling: a review Peer-reviewed

Yasuhiro Niimi, YoshiChika Otani

REPORTS ON PROGRESS IN PHYSICS　78　(12)　124501-124501　2015/12

DOI： 10.1088/0034-4885/78/12/124501 　

ISSN： 0034-4885

eISSN： 1361-6633
Spin relaxation mechanism in a highly doped organic polymer film

Motoi Kimata, Daisuke Nozaki, Yasuhiro Niimi, Hiroyuki Tajima, Yoshichika Otani

Physical Review B - Condensed Matter and Materials Physics　91　(22)　2015/06/17

DOI： 10.1103/PhysRevB.91.224422 　

ISSN： 1098-0121

eISSN： 1550-235X
Selective mode excitation in three-chained magnetic vortices Peer-reviewed

Norinobu Hasegawa, Satoshi Sugimoto, Hiroaki Fujimori, Kouta Kondou, Yasuhiro Niimi, YoshiChika Otani

APPLIED PHYSICS EXPRESS　8　(6)　2015/06

DOI： 10.7567/APEX.8.063005 　

ISSN： 1882-0778

eISSN： 1882-0786
Spin injection into superconductors and quasi-particle mediated spin Hall effects

Yoshichika Otani

Ieee Magnetics Conference (intermag)　2015

DOI： 10.1109/INTMAG.2015.7156645 　
Tunable configurational anisotropy in collective magnetization dynamics of Ni₈₀Fe₂₀ nanodot arrays with varying dot shapes

Mahato, B.K., Choudhury, S., Mandal, R., Barman, S., Otani, Y., Barman, A.

Journal of Applied Physics　117　(21)　2015

DOI： 10.1063/1.4921976 　

ISSN： 1089-7550 0021-8979
Strong Suppression of the Spin Hall Effect in the Spin Glass State

Niimi, Y., Kimata, M., Omori, Y., Gu, B., Ziman, T., Maekawa, S., Fert, A., Otani, Y.

Physical Review Letters　115　(19)　2015

DOI： 10.1103/PhysRevLett.115.196602 　

ISSN： 1079-7114 0031-9007
Spin transport in carbon nanotubes and graphene: Experiments and theory

Anane, A., Dlubak, B., Idzuchi, H., Jaffres, H., Martin, M.-B., Otani, Y., Seneor, P., Fert, A.

Handbook of Spintronics　2015

DOI： 10.1007/978-94-007-6892-5_27 　
Tunable picosecond spin dynamics in two dimensional ferromagnetic nanodot arrays with varying lattice symmetry

Saha, S., Barman, S., Sugimoto, S., Otani, Y., Barman, A.

RSC Advances　5　(43)　2015

DOI： 10.1039/c5ra02543e 　

ISSN： 2046-2069
Tunable spin wave spectra in two-dimensional Ni₈₀Fe₂₀ antidot lattices with varying lattice symmetry

Mandal, R., Barman, S., Saha, S., Otani, Y., Barman, A.

Journal of Applied Physics　118　(5)　2015

DOI： 10.1063/1.4928082 　

ISSN： 1089-7550 0021-8979
All-optical investigation of tunable picosecond magnetization dynamics in ferromagnetic nanostripes with a width down to 50 nm

Saha, S., Barman, S., Otani, Y., Barman, A.

Nanoscale　7　(43)　2015

DOI： 10.1039/c5nr05634a 　

ISSN： 2040-3372 2040-3364
Realization of a micrometre-scale spin-wave interferometer

Rousseau, O., Rana, B., Anami, R., Yamada, M., Miura, K., Ogawa, S., Otani, Y.

Scientific Reports　5　2015

DOI： 10.1038/srep09873 　

ISSN： 2045-2322
Revisiting the measurement of the spin relaxation time in graphene-based devices

Idzuchi, H., Fert, A., Otani, Y.

Physical Review B - Condensed Matter and Materials Physics　91　(24)　2015

DOI： 10.1103/PhysRevB.91.241407 　

ISSN： 1550-235X 1098-0121
Crossover between spin swapping and Hall effect in disordered systems

Saidaoui, H.B., Otani, Y., Manchon, A.

Physical Review B - Condensed Matter and Materials Physics　92　(2)　2015

DOI： 10.1103/PhysRevB.92.024417 　

ISSN： 1550-235X 1098-0121
Spin relaxation characteristics in Ag nanowire covered with various oxides

Karube, S., Idzuchi, H., Kondou, K., Fukuma, Y., Otani, Y.

Applied Physics Letters　107　(12)　2015

DOI： 10.1063/1.4931697 　

ISSN： 0003-6951
Quasiparticle-mediated spin Hall effect in a superconductor

Wakamura, T., Akaike, H., Omori, Y., Niimi, Y., Takahashi, S., Fujimaki, A., Maekawa, S., Otani, Y.

Nature Materials　14　(7)　2015

DOI： 10.1038/nmat4276 　

ISSN： 1476-4660 1476-1122
17pCG-1 Spin current generation from Mn oxide

Kondou K., Nakamura M., Idzuchi H., Matsuno J., Fukuma Y., Kawasaki M., Tokura Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　881-881　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_881 　

ISSN： 2189-079X
17aCG-5 Nonreciprocal spin-wave propagation in a chiral-lattice ferromagnetic insulator Cu2OSeO3

Seki S., Okamura Y., Kondou K., Shibata K., Kubota M., Takagi R., Kagawa F., Kawasaki M., Tatara G., Otani Y., Tokura Y.

Meeting Abstracts of the Physical Society of Japan　70　857-857　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_857 　

ISSN： 2189-079X
17aCG-8 Observation of enhanced spin relaxation at non-magnetic metal/Bi2O3 interface

Karube S., Idzuchi H., Kondou K., Fukuma Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　860-860　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_860 　

ISSN： 2189-079X
18aCM-9 Anisotropic anomalous Hall effect in EuNiGe_3

Kimata M., Omori Y., Takizawa S., Akamine H., Ashitomi Y., Hedo M., Nakama T., Onuki Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　925-925　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_925 　

ISSN： 2189-079X
21aAD-5 Inverse spin Hall effect in CuIr dilute alloys measured by means of spin pumping method

Takizawa S., Omori Y., Wakamura T., Kimata M., Niimi Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　958-958　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.1.0_958 　

ISSN： 2189-079X
21pPSA-14 Electron spin resonance of conduction electron spin current

Kimata M., Niimi Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　1087-1087　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.1.0_1087 　

ISSN： 2189-079X
16pPSA-24 Size effect in electrical transport properties of an antiferromagnet with a non-coplanar spin structure

Uchida Y., Kimata M., Higo T., Nakatsuji S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　836-836　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_836 　

ISSN： 2189-079X
16pPSA-15 Magnetic property of ultrathin EuS films

Muduli P. K., Wakamura Taro, Kimata Motoi, Otani Yoshichika

Meeting Abstracts of the Physical Society of Japan　70　827-827　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_827 　

ISSN： 2189-079X
16pPSA-13 Electrical transport property of micro fabricated FeRh film near the magnetic transition temperature

Matsumoto K., Kimata M., Taniuchi T., Shin S., Temple R., Marrows C. H., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　825-825　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_825 　

ISSN： 2189-079X
16pPSA-37 Modulation of spin wave modes in a magnetic vortex by a perpendicular magnetic field

Hasegawa N., Kondou K., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　849-849　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.2.0_849 　

ISSN： 2189-079X
21pPSA-19 Mutual spin pumping in ferromagnetic hetero-structures

Hasegawa N., Takizawa S., Kondou K., Kimata M., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　1092-1092　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.1.0_1092 　

ISSN： 2189-079X
21pPSA-10 Bi_2O_3 thickness dependence of spin to charge conversion induced at Non-magnetic metals/Bi_2O_3 interface

Karube S., Kondou K., Fukuma Y., Otani Y.

Meeting Abstracts of the Physical Society of Japan　70　1083-1083　2015
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.70.1.0_1083 　

ISSN： 2189-079X
Critical exponents and domain structures of magnetic semiconductor EuS and Gd-doped EuS films near Curie temperature

Hiroshi Idzuchi, Yasuhiro Fukuma, Hyun Soon Park, Tsuyoshi Matsuda, Toshiaki Tanigaki, Shinji Aizawa, Manabu Shirai, Daisuke Shindo, YoshiChika Otani

APPLIED PHYSICS EXPRESS　7　(11)　113002-113002　2014/11

DOI： 10.7567/APEX.7.113002 　

ISSN： 1882-0778

eISSN： 1882-0786
The 2014 Magnetism Roadmap Peer-reviewed

Robert L. Stamps, Stephan Breitkreutz, Johan Akerman, Andrii V. Chumak, YoshiChika Otani, Gerrit E. W. Bauer, Jan-Ulrich Thiele, Martin Bowen, Sara A. Majetich, Mathias Klaeui, Ioan Lucian Prejbeanu, Bernard Dieny, Nora M. Dempsey, Burkard Hillebrands

JOURNAL OF PHYSICS D-APPLIED PHYSICS　47　(33)　333001-1-333001-28　2014/08

DOI： 10.1088/0022-3727/47/33/333001 　

ISSN： 0022-3727

eISSN： 1361-6463
Modulation of effective damping constant using spin Hall effect

Shinya Kasai, Kouta Kondou, Hiroaki Sukegawa, Seiji Mitani, Kazuhito Tsukagoshi, Yoshichika Otani

APPLIED PHYSICS LETTERS　104　(9)　2014/03

DOI： 10.1063/1.4867649 　

ISSN： 0003-6951

eISSN： 1077-3118
Detection of a symmetric circular gyration of the vortex core via the second-order harmonic magnetoresistance oscillation Peer-reviewed

Satoshi Sugimoto, Norinobu Hasegawa, Yasuhiro Niimi, Yasuhiro Fukuma, Shinya Kasai, YoshiChika Otani

APPLIED PHYSICS EXPRESS　7　(2)　023006-023006　2014/02

DOI： 10.7567/APEX.7.023006 　

ISSN： 1882-0778

eISSN： 1882-0786
Width dependent transition of quantized spin-wave modes in Ni₈₀Fe₂₀ square nanorings

Banerjee, C., Saha, S., Barman, S., Rousseau, O., Otani, Y., Barman, A.

Journal of Applied Physics　116　(16)　2014

DOI： 10.1063/1.4900616 　

ISSN： 1089-7550 0021-8979
Effect of anisotropic spin absorption on the Hanle effect in lateral spin valves

Idzuchi, H., Fukuma, Y., Takahashi, S., Maekawa, S., Otani, Y.

Physical Review B - Condensed Matter and Materials Physics　89　(8)　2014

DOI： 10.1103/PhysRevB.89.081308 　

ISSN： 1098-0121 1550-235X
Thickness dependence of spin torque ferromagnetic resonance in Co ₇₅Fe₂₅/Pt bilayer films

Ganguly, A., Kondou, K., Sukegawa, H., Mitani, S., Kasai, S., Niimi, Y., Otani, Y., Barman, A.

Applied Physics Letters　104　(7)　2014

DOI： 10.1063/1.4865425 　

ISSN： 0003-6951
Propagation of nonlinearly generated harmonic spin waves in microscopic stripes

Rousseau, O., Yamada, M., Miura, K., Ogawa, S., Otani, Y.

Journal of Applied Physics　115　(5)　2014

DOI： 10.1063/1.4864480 　

ISSN： 1089-7550 0021-8979
Tunable spin wave dynamics in two-dimensional Ni₈₀Fe₂₀ nanodot lattices by varying dot shape

Mahato, B.K., Rana, B., Kumar, D., Barman, S., Sugimoto, S., Otani, Y., Barman, A.

Applied Physics Letters　105　(1)　2014

DOI： 10.1063/1.4890088 　

ISSN： 0003-6951
Inverse spin Hall effect in a closed loop circuit

Omori, Y., Auvray, F., Wakamura, T., Niimi, Y., Fert, A., Otani, Y.

Applied Physics Letters　104　(24)　2014

DOI： 10.1063/1.4884520 　

ISSN： 0003-6951
Extrinsic spin Hall effects measured with lateral spin valve structures

Niimi, Y., Suzuki, H., Kawanishi, Y., Omori, Y., Valet, T., Fert, A., Otani, Y.

Physical Review B - Condensed Matter and Materials Physics　89　(5)　2014

DOI： 10.1103/PhysRevB.89.054401 　

ISSN： 1550-235X 1098-0121
Detection of a symmetric circular gyration of the vortex core via the second order harmonic magnetoresistance oscillation (vol 7, 023006, 2014)

Yoshichika Otani

Applied Physics Express　2014

DOI： 10.7567/APEX.7.039202 　
Spin Injection into a Superconductor with Strong Spin-Orbit Coupling Peer-reviewed

T. Wakamura, N. Hasegawa, K. Ohnishi, Y. Niimi, YoshiChika Otani

PHYSICAL REVIEW LETTERS　112　(3)　036602-036602　2014/01

DOI： 10.1103/PhysRevLett.112.036602 　

ISSN： 0031-9007

eISSN： 1079-7114
5d iridium oxide as a material for spin-current detection Peer-reviewed

Kohei Fujiwara, Yasuhiro Fukuma, Jobu Matsuno, Hiroshi Idzuchi, Yasuhiro Niimi, YoshiChika Otani, Hidenori Takagi

NATURE COMMUNICATIONS　4　2893-2893　2013/12

DOI： 10.1038/ncomms3893 　

ISSN： 2041-1723
Experimental verification of comparability between spin-orbit and spin-diffusion lengths Peer-reviewed

Yasuhiro Niimi, Dahai Wei, Hiroshi Idzuchi, Taro Wakamura, Takeo Kato, Yoshichika Otani

Physical Review Letters　110　(1)　016805-016805　2013/01/03

DOI： 10.1103/PhysRevLett.110.016805 　

ISSN： 0031-9007 1079-7114
Erratum: Spin injection properties in trilayer graphene lateral spin valves (Applied Physics Letters (2013) 102 (033105))

Liu, Y.P., Idzuchi, H., Fukuma, Y., Rousseau, O., Otani, Y., Lew, W.S.

Applied Physics Letters　102　(7)　2013

DOI： 10.1063/1.4792318 　

ISSN： 0003-6951
Spin injection properties in trilayer graphene lateral spin valves

Liu, Y.P., Idzuchi, H., Fukuma, Y., Rousseau, O., Otani, Y., Lew, W.S.

Applied Physics Letters　102　(3)　2013

DOI： 10.1063/1.4776699 　

ISSN： 0003-6951
Configurational anisotropic spin waves in cross-shaped Ni ₈₀Fe₂₀ nanoelements

Mahato, B.K., Rana, B., Mandal, R., Kumar, D., Barman, S., Fukuma, Y., Otani, Y., Barman, A.

Applied Physics Letters　102　(19)　2013

DOI： 10.1063/1.4804990 　

ISSN： 0003-6951
Tunable magnonic spectra in two-dimensional magnonic crystals with variable lattice symmetry

Saha, S., Mandal, R., Barman, S., Kumar, D., Rana, B., Fukuma, Y., Sugimoto, S., Otani, Y., Barman, A.

Advanced Functional Materials　23　(19)　2013

DOI： 10.1002/adfm.201202545 　

ISSN： 1616-301X 1616-3028
Impact of interface properties on spin accumulation in dual-injection lateral spin valves

Idzuchi, H., Karube, S., Fukuma, Y., Aoki, T., Otani, Y.

Applied Physics Letters　103　(16)　2013

DOI： 10.1063/1.4824897 　

ISSN： 0003-6951
Nonlinear motion of magnetic vortex cores during fast magnetic pulses Peer-reviewed

Keiki Fukumoto, Kuniaki Arai, Takashi Kimura, Yoshichika Otani, Toyohiko Kinoshita

PHYSICAL REVIEW B　85　(13)　2012/04

DOI： 10.1103/PhysRevB.85.134414 　

ISSN： 2469-9950

eISSN： 2469-9969
Nonlocal Spin Valves in Metallic Nanostructures

Yoshichika Otani

Handbook of Spin Transport and Magnetism　2012

DOI： 10.1201/B11086-38 　
Giant spin hall effect induced by skew scattering from bismuth impurities inside thin film CuBi alloys

Niimi, Y., Kawanishi, Y., Wei, D.H., Deranlot, C., Yang, H.X., Chshiev, M., Valet, T., Fert, A., Otani, Y.

Physical Review Letters　109　(15)　2012

DOI： 10.1103/PhysRevLett.109.156602 　

ISSN： 0031-9007 1079-7114
PERFECT ALLOYS for SPIN HALL CURRENT-INDUCED MAGNETIZATION SWITCHING

Gradhand, M., Fedorov, D.V., Zahn, P., Mertig, I., Otani, Y., Niimi, Y., Vila, L., Fert, A.

SPIN　2　(2)　2012

DOI： 10.1142/S2010324712500105 　

ISSN： 2010-3255 2010-3247
Spin relaxation mechanism in silver nanowires covered with MgO protection layer

Idzuchi, H., Fukuma, Y., Wang, L., Otani, Y.

Applied Physics Letters　101　(2)　2012

DOI： 10.1063/1.4737001 　

ISSN： 0003-6951
The spin Hall effect as a probe of nonlinear spin fluctuations

Wei, D.H., Niimi, Y., Gu, B., Ziman, T., Maekawa, S., Otani, Y.

Nature Communications　3　2012

DOI： 10.1038/ncomms2063 　

ISSN： 2041-1723
Optically induced tunable magnetization dynamics in nanoscale Co antidot lattices

Mandal, R., Saha, S., Kumar, D., Barman, S., Pal, S., Das, K., Raychaudhuri, A.K., Fukuma, Y., Otani, Y., Barman, A.

ACS Nano　6　(4)　2012

DOI： 10.1021/nn300421c 　

ISSN： 1936-0851 1936-086X
Anisotropy in collective precessional dynamics in arrays of Ni ₈₀Fe ₂₀ nanoelements

Rana, B., Kumar, D., Barman, S., Pal, S., Mandal, R., Fukuma, Y., Otani, Y., Sugimoto, S., Barman, A.

Journal of Applied Physics　111　(7)　2012

DOI： 10.1063/1.3672402 　

ISSN： 0021-8979
Towards coherent spin precession in pure-spin current

Idzuchi, H., Fukuma, Y., Otani, Y.

Scientific Reports　2　2012

DOI： 10.1038/srep00628 　

ISSN： 2045-2322
Generation of Large Spin Accumulation in S/N/S Josephson Junctions Peer-reviewed

Taro Wakamura, Kohei Ohnishi, Yasuhiro Niimi, YoshiChika Otani

26TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT26), PTS 1-5　400　022130-022130　2012

DOI： 10.1088/1742-6596/400/2/022130 　

ISSN： 1742-6588
Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves Peer-reviewed

Yasuhiro Fukuma, Le Wang, Hiroshi Idzuchi, Saburo Takahashi, Sadamichi Maekawa, YoshiChika Otani

NATURE MATERIALS　10　(7)　527-531　2011/07

DOI： 10.1038/NMAT3046 　

ISSN： 1476-1122
Large Spin Accumulation with Long Spin Diffusion Length in Cu/MgO/Permalloy Lateral Spin Valves Peer-reviewed

Taro Wakamura, Kohei Ohnishi, Yasuhiro Niimi, YoshiChika Otani

APPLIED PHYSICS EXPRESS　4　(6)　063002-063002　2011/06

DOI： 10.1143/APEX.4.063002 　

ISSN： 1882-0778
Dynamics of Coupled Vortices in a Pair of Ferromagnetic Disks Peer-reviewed

Satoshi Sugimoto, Yasuhiro Fukuma, Shinya Kasai, Takashi Kimura, Anjan Barman, YoshiChika Otani

PHYSICAL REVIEW LETTERS　106　(19)　2011/05

DOI： 10.1103/PhysRevLett.106.197203 　

ISSN： 0031-9007

eISSN： 1079-7114
Dynamics of Magnetostatically Coupled Vortices Observed by Time-Resolved Photoemission Electron Microscopy Peer-reviewed

Kuniaki Arai, Taichi Okuda, Keiki Fukumoto, Masato Kotsugi, Takuo Ohkouchi, Kenji Kodama, Takashi Kimura, Yuichi Haruyama, Tetsuya Nakamura, Tomohiro Matsushita, Hitoshi Osawa, Takayuki Muro, Shinji Matsui, Akito Kakizaki, YoshiChika Otani, Toyohiko Kinoshita

JAPANESE JOURNAL OF APPLIED PHYSICS　50　(5)　053001　2011/05

DOI： 10.1143/JJAP.50.053001 　

ISSN： 0021-4922
Demonstration of spin valve effects in silicon nanowires Peer-reviewed

Jean Tarun, Shaoyun Huang, Yasuhiro Fukuma, Hiroshi Idzuchi, YoshiChika Otani, Naoki Fukata, Koji Ishibashi, Shunri Oda

JOURNAL OF APPLIED PHYSICS　109　(7)　2011/04

DOI： 10.1063/1.3562904 　

ISSN： 0021-8979
Control of magnetic domain wall displacement using spin current in small in-plane magnetic field in Permalloy nanowires Peer-reviewed

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Akira Tonomura, Yoshichika Otani

Journal of Physics D: Applied Physics　44　(6)　064015-064015　2011/02/16

DOI： 10.1088/0022-3727/44/6/064015 　

ISSN： 0022-3727

eISSN： 1361-6463
All-optical excitation and detection of picosecond dynamics of ordered arrays of nanomagnets with varying areal density

Rana, B., Pal, S., Barman, S., Fukuma, Y., Otani, Y., Barman, A.

Applied Physics Express　4　(11)　2011

DOI： 10.1143/APEX.4.113003 　

ISSN： 1882-0778 1882-0786
Spin current related phenomena in metallic nano-structures Peer-reviewed

YoshiChika Otani, Takashi Kimura

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES　43　(3)　735-740　2011/01

DOI： 10.1016/j.physe.2010.07.041 　

ISSN： 1386-9477
Stochastic Nature of Current-Excited Magnetic Domain and Domain Wall Dynamics Microscopically Investigated by Lorentz Microscopy

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Akira Tonomura, Yoshichika Otani

TENCON 2010: 2010 IEEE REGION 10 CONFERENCE　122-125　2010

DOI： 10.1109/TENCON.2010.5685851 　

ISSN： 2159-3442
Magneto-optical and spin-transfer switching properties of current-perpendicular-to plane spin valves with perpendicular magnetic anisotropy Peer-reviewed

Ken Ichi Aoshima, Nobuhiko Funabashi, Kenji Machida, Yasuyoshi Miyamoto, Norikazu Kawamura, Kiyoshi Kuga, Naoki Shimidzu, Takashi Kimura, Yoshichika Otani, Fumio Sato

IEEE Transactions on Magnetics　44　(11 PART 2)　2491-2495　2008/11

DOI： 10.1109/TMAG.2008.2002615 　

ISSN： 0018-9464
Spin Current and Spin Hall Effect in Metallic Nano-Structures

Yoshichika Otani, Takashi Kimura

IEEE Transactions on Magnetics　44　1911-1915　2008/07/01
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/tmag.2008.924535 　

ISSN： 0018-9464

More details Close

Laterally configured ferromagnetic/nonmagnetic multiterminal structures have great potential for developing future spintronic devices. We demonstrate two kinds of novel spintronic devices. One is a lateral spin valve with noncollinear dual spin injectors by which the direction of the spin accumulation in a nonmagnetic metal can be changed by varying the currents injected by two spin injectors. The other is a transformer between spin and charge currents using the spin Hall effect. A large spin Hall conductivity of 260 S/cm at room temperature, which is 104 times larger than that in semiconductor systems, is found in the Pt wire. We also demonstrate the reciprocal relation between the spin and charge currents. Temperature dependence of the spin Hall conductivity is also discussed.
Construction and development of a time-resolved x-ray magnetic circular dichroism-photoelectron emission microscopy system using femtosecond laser pulses at BL25SU SPring-8 Peer-reviewed

Keiki Fukumoto, Tomohiro Matsushita, Hitoshi Osawa, Tetsuya Nakamura, Takayuki Muro, Kuniaki Arai, Takashi Kimura, Yoshichika Otani, Toyohiko Kinoshita

REVIEW OF SCIENTIFIC INSTRUMENTS　79　(6)　2008/06

DOI： 10.1063/1.2937648 　

ISSN： 0034-6748

eISSN： 1089-7623
Detection of paired domain walls in a ferromagnetic ring by a bend resistance measurement Peer-reviewed

Masahiro Hara, Takashi Kimura, Yoshichika Otani

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES　40　(5)　1108-1110　2008/03

DOI： 10.1016/j.physe.2007.08.031 　

ISSN： 1386-9477
Improvement of superconductive properties of mesoscopic Nb wires by Ti passivation layers Peer-reviewed

Kohei Ohnishi, Takashi Kimura, Yoshichika Otani

APPLIED PHYSICS EXPRESS　1　(2)　2008/02

DOI： 10.1143/APEX.1.021701 　

ISSN： 1882-0778
Current-excited magnetization reversal under in-plane magnetic field in a nanoscaled ferromagnetic wire Peer-reviewed

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Tsuyoshi Matsuda, Akira Tonomura, Yoshichika Otani, Tetsuya Akashi

Applied Physics Letters　92　(1)　012505　2008

DOI： 10.1063/1.2828865 　

ISSN： 0003-6951
Evolution of the spin hall effect in Pt nanowires: Size and temperature effects Peer-reviewed

Laurent Vila, Takashi Kimura, YoshiChika Otani

PHYSICAL REVIEW LETTERS　99　(22)　2007/11

DOI： 10.1103/PhysRevLett.99.226604 　

ISSN： 0031-9007
Electrical control of the direction of spin accumulation Peer-reviewed

Takashi Kimura, YoshiChika Otani, Peter M. Levy

PHYSICAL REVIEW LETTERS　99　(16)　2007/10

DOI： 10.1103/PhysRevLett.99.166601 　

ISSN： 0031-9007

eISSN： 1079-7114
Controlled depinning of domain walls in a ferromagnetic ring circuit Peer-reviewed

Masahiro Hara, Takashi Kimura, Yoshichika Otani

APPLIED PHYSICS LETTERS　90　(24)　2007/06

DOI： 10.1063/1.2748339 　

ISSN： 0003-6951
Magnetization process in a ferromagnetic disk measured by a semiconductor two-dimensional electron gas Peer-reviewed

Masahiro Hara, Yoshichika Otani

JOURNAL OF APPLIED PHYSICS　101　(5)　2007/03

DOI： 10.1063/1.2710435 　

ISSN： 0021-8979
19pZC-8 Spin-Current Interference in a Cu Nano-Ring

Hirohata A., Yang T., Kimura T., Otani Y.

Meeting Abstracts of the Physical Society of Japan　62.1.3　464　2007
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.62.1.3.0_464_1 　

eISSN： 2189-0803
Observation of coupled magnetic vortex structure dynamics by time-resolved magneto-optical Kerr effect microscopy Peer-reviewed

Roman Antos, Jaroslav Hamrle, Hiroaki Masaki, Takashi Kimura, Junya Shibata, Yoshichika Otani

QUANTUM SENSING AND NANOPHOTONIC DEVICES IV　6479　2007

DOI： 10.1117/12.696264 　

ISSN： 0277-786X
Observation of Current-Excited Magnetization Dynamics using Field-Emission Transmission Electron Microscope

Yoshihiko TOGAWA, Ken HARADA, Tsuyoshi MATSUDA, Akira TONOMURA, Tetsuya AKASHI, Takashi KIMURA, Yoshichika OTANI

Nihon Kessho Gakkaishi　49　(5)　307-312　2007
Publisher: The Crystallographic Society of Japan
DOI： 10.5940/jcrsj.49.307 　

ISSN： 0369-4585

eISSN： 1884-5576
Spin transfer switching in current-perpendicular-to-plane spin valve observed by magneto-optical Kerr effect using visible light Peer-reviewed

Ken Ichi Aoshima, Nobuhiko Funabashi, Kenji MacHida, Yasuyoshi Miyamoto, Norikazu Kawamura, Kiyoshi Kuga, Naoki Shimidzu, Fumio Sato, Takashi Kimura, Yoshichika Otani

Applied Physics Letters　91　(5)　2007

DOI： 10.1063/1.2767770 　

ISSN： 0003-6951
Domain nucleation and annihilation in uniformly magnetized state under current pulses in narrow ferromagnetic wires Peer-reviewed

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Tetsuya Akashi, Tsuyoshi Matsuda, Akira Tonomura, Yoshichika Otani

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　45　(46-50)　L1322-L1324　2006/12

DOI： 10.1143/JJAP.45.L1322 　

ISSN： 0021-4922
Control of domain wall pinning by a switchable magnetic gate Peer-reviewed

Masahiro Hara, Junya Shibata, Takashi Kimura, Yoshichika Otani

APPLIED PHYSICS LETTERS　89　(19)　2006/11

DOI： 10.1063/1.2385224 　

ISSN： 0003-6951
Current-excited magnetization dynamics in narrow ferromagnetic wires Peer-reviewed

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Tetsuya Akashi, Tsuyoshi Matsuda, Akira Tonomura, Yoshichika Otani

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　45　(24-28)　L683-L685　2006/07

DOI： 10.1143/JJAP.45.L683 　

ISSN： 0021-4922
Manipulation of the magnetic state of a small ferromagnetic particle by means of nonlocal spin-injection techniques (invited)

Takashi Kimura, Yoshichika Otani

Journal of Applied Physics　99　2006/04/15
Publisher: AIP Publishing
DOI： 10.1063/1.2162031 　

ISSN： 0021-8979

eISSN： 1089-7550

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<jats:p>Nonlocal spin-valve configuration is used for spin current injection into a nanoscale ferromagnetic particle to reverse its magnetization. The nonlocal spin injection aligns the magnetization of the nanoscale particle along the spin injector, whereas the reverse switching is hardly observed up to the available maximum exciting current of about 15 mA. This asymmetric behavior implies the presence of asymmetric barrier formed in the vicinity of the interface. The magnitude of the essential spin current for the reversal is determined to be about 160μA, on the reasonable order of magnitude compared with the experimental values for conventional pillar structures.</jats:p>
23pXH-1 Spin-Current Interference in a Cu Nano-Ring

Hirohata A., Yang T., Kimura T., Otani Y.

Meeting Abstracts of the Physical Society of Japan　61.2.3　344　2006
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.61.2.3.0_344_3 　

eISSN： 2189-0803
28pSC-6 Quantum Spin Interference in a Cu Nano-Ring

Hirohata A., Y. Tao, Kimura T., Otani Y.

Meeting Abstracts of the Physical Society of Japan　61.1.3　480　2006
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.61.1.3.0_480_4 　

eISSN： 2189-0803
Detection of magnetic state in a nanoscale ferromagnetic ring by using ballistic semiconductor two-dimensional electron gas Peer-reviewed

Masahiro Hara, Junya Shibata, Takashi Kimura, Yoshichika Otani

Applied Physics Letters　88　(8)　2006

DOI： 10.1063/1.2177358 　

ISSN： 0003-6951
Current distribution inside Py/Cu lateral spin-valve devices Peer-reviewed

J Hamrle, T Kimura, Y Otani, K Tsukagoshi, Y Aoyagi

PHYSICAL REVIEW B　71　(9)　094402　2005/03

DOI： 10.1103/PhysRevB.71.094402 　

ISSN： 1098-0121
Suppression of spin accumulation in nonmagnet due to ferromagnetic ohmic contact Peer-reviewed

T Kimura, J Hamrle, Y Otani, K Tsukagoshi, Y Aoyagi

APPLIED PHYSICS LETTERS　85　(17)　3795-3796　2004/10

DOI： 10.1063/1.1811801 　

ISSN： 0003-6951
Domain wall drag due to dc current injection into ferromagnetic nano-wires Peer-reviewed

T. Kimura, Y. Otani, I. Yagi, K. Tsukagoshi, Y. Aoyagi

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1347-E1348　2004/05

DOI： 10.1016/j.jmmm.2003.12.205 　

ISSN： 0304-8853
Non-local Hall resistance measured in submicron-scale non-magnetic/ferromagnetic junctions Peer-reviewed

T. Kimura, Y. Otani, K. Tsukagoshi, Y. Aoyagi

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1333-E1334　2004/05

DOI： 10.1016/j.jmmm.2003.12.197 　

ISSN： 0304-8853
Suppressed pinning field of a trapped domain wall due to direct current injection Peer-reviewed

T Kimura, Y Otani, Yagi, I, K Tsukagoshi, Y Aoyagi

JOURNAL OF APPLIED PHYSICS　94　(11)　7266-7269　2003/12

DOI： 10.1063/1.1618941 　

ISSN： 0021-8979
Spin-current-assisted domain-wall depinning in a submicron magnetic wire Peer-reviewed

T Kimura, Y Otani, K Tsukagoshi, Y Aoyagi

JOURNAL OF APPLIED PHYSICS　94　(12)　7947-7949　2003/12

DOI： 10.1063/1.1629150 　

ISSN： 0021-8979
1P-PSB-65 Surface observation of magnetic structure in FeNi martensites by means of MFM

Hirohata A., Otani Y., Miyajima H.

Meeting Abstracts of the Physical Society of Japan　51.3　199　1996
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyog.51.3.0_199_2 　

eISSN： 2433-1112
Magnetism in Body-Centered Tetragonal FeRh1-xPdx Alloys (II) Band Structure

Sakuma Akimasa, Yuasa Shinji, Miyajima Hideki, Otani Yoshichika

J Phys Soc Jpn　64　(12)　4914-4922　1995/12/15

DOI： 10.1143/JPSJ.64.4914 　

ISSN： 0031-9015
Change in the Resistivity of bcc and bct FeRh Alloys at First-Order Magnetic Phase Transitions

Yuasa Shinji, Akiyama Takashi, Miyajima Hideki, Otani Yoshichika

J Phys Soc Jpn　64　(10)　3978-3985　1995/10/15

DOI： 10.1143/JPSJ.64.3978 　

ISSN： 0031-9015
Magneto-Volume and Tetragonal Elongation Effects on Magnetic Phase Transitions of Body-Centered Tetragonal FeRh1-xPtx

Yuasa Shinji, Miyajima Hideki, Otani Yoshichika

J Phys Soc Jpn　63　(8)　3129-3144　1994/08/15

DOI： 10.1143/JPSJ.63.3129 　

ISSN： 0031-9015
First-Order Magnetic Phase Transition in bcc FeRh–Ir Alloy under High Pressures up to 6.2 GPa

Yuasa Shinji, Miyajima Hideki, Otani Yoshichika, Tsuji Kazuhiko, Katayama Yoshinori, Kusumi Kazuhisa, Yokoyama Hiroyuki, Yaoita Kenichi, Shimomura Osamu

J Phys Soc Jpn　63　(3)　855-858　1994/03/15

DOI： 10.1143/JPSJ.63.855 　

ISSN： 0031-9015
Magnetic Properties of bcc FeRh#D1-XM#DX Systems Peer-reviewed

Shinji Yuasa, Yoshichika Ohtani, Hideki Miyajima, Akimasa Sakuma

JOURNAL OF THE MAGNETIC SOCIETY OF JAPAN　18　(2)　235-240　1994

DOI： 10.3379/jmsjmag.18.235

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Misc. 26

Emergence of spin-charge conversion functionalities due to spatial and time-reversal asymmetries and chiral symmetry

Kouta Kondou, Yoshichika Otani

FRONTIERS IN PHYSICS　11　2023/03

DOI： 10.3389/fphy.2023.1140286 　

ISSN： 2296-424X
Towards magnonic devices based on voltage-controlled magnetic anisotropy

Bivas Rana, YoshiChika Otani

Communications Physics　2　(1)　2019/12/01
Publisher: Nature Research
DOI： 10.1038/s42005-019-0189-6 　

ISSN： 2399-3650
Skyrmion creation in Pt/Co/Ir trilayer by using surface acoustic waves

Yokouchi T., Sugimoto S., Rana B., Seki S., Ogawa N., Kasai S., Otani Y.

Meeting Abstracts of the Physical Society of Japan　74.1　1268-1268　2019
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.74.1.0_1268 　

eISSN： 2189-0803
カイラル反強磁性体Mn₃Snの超高速スピンダイナミクス

三輪真嗣, 三輪真嗣, 三輪真嗣, 飯浜賢志, 飯浜賢志, 野本拓也, 野本拓也, 冨田崇弘, 冨田崇弘, 肥後友也, 肥後友也, MUHAMMAD Ikhlas, 大谷義近, 大谷義近, 大谷義近, 水上成美, 水上成美, 水上成美, 有田亮太郎, 有田亮太郎, 有田亮太郎, 中辻知, 中辻知, 中辻知

日本物理学会講演概要集(CD-ROM)　74　(2)　2019

ISSN： 2189-079X
Effect of excitation power on voltage induced local magnetization dynamics in an ultrathin CoFeB film

Bivas Rana, Yasuhiro Fukuma, Katsuya Miura, Hiromasa Takahashi, Yoshichika Otani

Scientific Reports　7　(1)　2017/12/01
Publisher: Nature Publishing Group
DOI： 10.1038/s41598-017-02427-3 　

ISSN： 2045-2322

eISSN： 2045-2322
Excitation of coherent propagating spin waves in ultrathin CoFeB film by voltage-controlled magnetic anisotropy

Bivas Rana, Yasuhiro Fukuma, Katsuya Miura, Hiromasa Takahashi, YoshiChika Otani

APPLIED PHYSICS LETTERS　111　(5)　2017/07

DOI： 10.1063/1.4990724 　

ISSN： 0003-6951

eISSN： 1077-3118
Spin Current Generation by Using Surfaces and Interfaces

72　(5)　320-327,317　2017/05
Publisher: 日本物理学会
ISSN： 0029-0181
Voltage-induced magnetization dynamics in CoFeB/MgO/CoFeB magnetic tunnel junctions

Katsuya Miura, Shin Yabuuchi, Masaki Yamada, Masahiko Ichimura, Bivas Rana, Susumu Ogawa, Hiromasa Takahashi, Yasuhiro Fukuma, Yoshichika Otani

Scientific Reports　7　2017/02/17

DOI： 10.1038/srep42511 　

ISSN： 2045-2322

eISSN： 2045-2322
Tips for spintronics experiments : Spin current measurements

86　(2)　139-143　2017/02
Publisher: 応用物理学会
ISSN： 0369-8009
21pBC-7 Fermi level dependent charge-to-spin current conversion by Dirac surface state of topological insulators

Kondou K, Yoshimi R, Tsukazaki A, Fukuma Y, Matsuno J, Takahashi K. S, Kawasaki M, Tokura Y, Otani Y

日本物理学会講演概要集　71　(1)　1262-1262　2016/03/19
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/jpsgaiyo.71.1.0_1262 　

ISSN： 2189-079X
Spin transport in non-magnetic nano-structures induced by non-local spin injection

Hiroshi Idzuchi, Yasuhiro Fukuma, Yoshichika Otani

Physica E: Low-Dimensional Systems and Nanostructures　68　239-263　2015/04

DOI： 10.1016/j.physe.2014.11.023 　

ISSN： 1386-9477

eISSN： 1873-1759
17aCG-6 Non-reciprocity of Spin Wave Propagation in B20 Chiral Magnet

Takagi R., Otani Y., Tokura Y., Seki S., Okamura Y., Kondo K., Kanazawa N., Morikawa D., Shibata K., Kikkawa A., Tatara G.

Meeting Abstracts of the Physical Society of Japan　70　(0)　858-858　2015
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.70.2.0_858 　

ISSN： 2189-079X
28pAF-7 Estimation of spin diffusion length using spin-torque ferromagnetic resonance in NiFe/Cu/Pt trilayer film

Kondou K., Niimi Y., Otani Y.

Meeting abstracts of the Physical Society of Japan　69　(1)　517-517　2014/03/05
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
Temperature Evolution of Spin-Polarized Electron Tunneling in Silicon Nanowire-Permalloy Lateral Spin Valve System

Jean Tarun, Shaoyun Huang, Yasuhiro Fukuma, Hiroshi Idzuchi, YoshiChika Otani, Naoki Fukata, Koji Ishibashi, Shunri Oda

APPLIED PHYSICS EXPRESS　5　(4)　045001　2012/04

DOI： 10.1143/APEX.5.045001 　

ISSN： 1882-0778
Manipulation of spin currents in metallic systems

Yoshichika Otani, Takashi Kimura

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES　369　(1948)　3136-3149　2011/08

DOI： 10.1098/rsta.2011.0010 　

ISSN： 1364-503X
Spin Diffusion Characteristics in Magnesium Nanowires (vol 3, 063002, 2010)

Hiroshi Idzuchi, Yasuhiro Fukuma, Le Wang, YoshiChika Otani

APPLIED PHYSICS EXPRESS　4　(4)　2011/04

DOI： 10.1143/APEX.4.049202 　

ISSN： 1882-0778
Crystalline analysis of permalloy narrow wires subject to current pulses

Yoshihiko Togawa, Kazuya Takayanagi, Takashi Kimura, Ken Harada, Tetsuya Akashi, Akira Tonomura, Shigeo Mori, Yoshichika Otani

JOURNAL OF APPLIED PHYSICS　107　(9)　1954　2010/05

DOI： 10.1063/1.3356229 　

ISSN： 0021-8979

eISSN： 1089-7550
Lorentz microscopy and electron holography studies of current-excited magnetization dynamics in Permalloy nanowires

Yoshihiko Togawa, Takashi Kimura, Ken Harada, Tetsuya Akashi, Tsuyoshi Matsuda, Akira Tonomura, Yoshichika Otani

Spintronics (SPIE NanoScience and Engineering)　7036　703617-703620　2008/08/28
Publisher: SPIE
DOI： 10.1117/12.798102 　
Magnetic vortex dynamics

Roman Antos, YoshiChika Otani, Junya Shibata

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　77　(3)　031004-1-8　2008/03

DOI： 10.1143/JPSJ.77.031004 　

ISSN： 0031-9015
21pQG-13 Observation of magnetic vortex core dynamics in magneto statically coupled micron-sized magnetic disks

Arai K., Kakizaki A., Kinoshita T., Fukumoto K., Okuda T., Nakamura T., Kimura T., Matsushita T., Osawa H., Muro T., Otani Y.

Meeting Abstracts of the Physical Society of Japan　63　(0)　381-381　2008
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.63.2.3.0_381_3 　

ISSN： 1342-8349
18pZC-14 Dynamics of paired domain walls in a ferromagnetic ring under a pulsed magnetic field

Hara Masahiro, Otani Yoshichika

Meeting abstracts of the Physical Society of Japan　62　(1)　445-445　2007/02/28
Publisher: The Physical Society of Japan (JPS)
ISSN： 1342-8349
24aTK-10 Time-resolved XMCD-PEEM using femtosecond pulsed laser

Fukumoto K., Kinoshita T., Osawa H., Matsushita T., Arai K., Nakamura T., Muro T., Kimura T., Otani Y., Kakizaki A.

Meeting Abstracts of the Physical Society of Japan　62　(0)　788-788　2007
Publisher: The Physical Society of Japan
DOI： 10.11316/jpsgaiyo.62.2.4.0_788_2 　

ISSN： 1342-8349
Interplay between Magnetic Domain Walls and Electron Transport in Nano-Scale Ferromagnets

Otani Yoshichika, Kim Seung Gu, Fukamichi Kazuaki

54　(7)　528-535　1999
Publisher: The Physical Society of Japan (JPS)
DOI： 10.11316/butsuri1946.54.528 　

ISSN： 0029-0181
Magnetization Reversal Process in Submicron Epitaxial (10・0) Co Dot Arrays

T. Kohda, Y. Otani, S. G. Kim, K. Fukamichi, O. Kitakami, Y. Shimada

J. Magn. Soc. Jnp.　23　(4-1)　939-942　1999
Publisher: The Magnetics Society of Japan
DOI： 10.3379/jmsjmag.23.939 　

ISSN： 0285-0192 1880-4004

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Epitaxial arrays of (10·0) Co circular dots with diameters of 0.3 μm and 2.0 μm were prepared by electron-beam lithography and Ar ion etching. Magnetization reversal processes influenced by well-defined magnetocrystalline anisotropy were examined with a magnetic force microscope (MFM) and a vector SQUID magnetometer. The coercive force of both dot arrays is lower than that of an epitaxial Co film. From MFM and vector magnetization measurements, a magnetic vortex-like structure was found to be formed during the demagnetization process for a 0.3 μm circular dot array. In contrast, a symmetrical domain structure was formed during the demagnetization process for a 2.0 μm dot array.
Observation of magnetic domain structure in martensite by means of MFM

HIROHATA A., YUASA S., OTANI Y., MIYAJIMA H.

19　55　1995/09/01
Magnetism of Body-Centered Tetragonal FeRh1−xPdx Alloys (I) Magnetic Properties

Shinji Yuasa, Hideki Miyajima, Yoshichika Otani, Akimasa Sakuma

Journal of the Physical Society of Japan　64　(12)　4906-4913　1995

DOI： 10.1143/JPSJ.64.4906 　

ISSN： 1347-4073 0031-9015

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Research Projects 27

Chimera Quasiparticles: Physics

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Transformative Research Areas (A)

Institution: Keio University

2024/04 - 2029/03
人材育成と量子スピントロニクス技術の基盤確立に向けた日仏共同イニシアティブ

大谷義近

Offer Organization: 科学技術振興機構

Category: 国際的な科学技術共同研究などの推進/先端国際共同研究推進事業/ASPIRE/単独公募(トップ)

2024 - 2029

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日仏の世界をリードするトップ研究グループを集結することで、固体中の電荷、電子スピン、軌道モーメント、マグノン、カイラルフォノンなどの量子力学的準粒子のダイナミクス、量子伝導、超伝導や磁性との相互作用から発現する量子現象を製膜・素子作製から最先端測定・解析・素子応用まで一気通貫で研究する。これにより、量子スピントロニクス技術の学術的な発展と当該分野を国際的にリードする次世代研究者を育成する。東大物性研に新設された量子ナノラボを基軸として、世界最先端の非線形分光技術を有効に活用して一気通貫の研究を推進する。実験と理論で世界をリードするフランス人研究者が有機的に本連携研究を推進する。効率的な連携研究のために物性研とグルノーブルの研究所内に連携ハブ研究室を設ける。
Magnon-phonon coupling at the van der Waals interface and its heterostructure

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for JSPS Fellows

Institution: Institute of Physical and Chemical Research

2021/11/18 - 2024/03/31
Efficient spin current generation based on coherent magnetoelastic strong coupling state

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (S)

Institution: Institute of Physical and Chemical Research

2019/06/26 - 2024/03/31
Conversion Mechanism of Spin and Mechanical Rotation

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: Institute of Physical and Chemical Research

2020/04/01 - 2023/03/31
Summary of nano-spin conversion science project

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

Institution: The University of Tokyo

2019/04/01 - 2020/03/31
Formation of an international strategic base for the nano-spin conversion science

OTANI Yoshichika, SHIRAISHI Masashi, OIWA Akira, SAITOH Eiji, MURAKAMI Shuichi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

Institution: The University of Tokyo

2015/11/06 - 2019/03/31

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Based on international collaboration in this research field, we formed an international network among the researchers engaged in the research field of spin conversion science. We organized several international conferences including tutorial sessions on spintronics for young researchers. Moreover, in order to foster Asian young researchers specialized in spintronics, we have held the international school of spintronics every year during last 4 years in collaboration with Korean research institutes. This activity surely helped developing human resources who will lead the spin conversion research industrially as well as academically. Additionally, participation of young graduate students and staff members at the universities in the international collaboration bore fruit as an internationally recognized achievement.
Magnetic spin conversion

Otani Yoshichika, ONO Teruo

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

Institution: The University of Tokyo

2014/07/10 - 2019/03/31

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In this research project, we studied following two subjects, 1) development of non-linear spin charge currents conversion and 2) exploration of novel interfacial spin-charge currents conversion. As a result, we discovered strong suppression of the spin Hall effect in the spin grass state. We found a strong enhancement of the spin Hall effect in superconductors and clarified the mechanism experimentally and theoretically. Apart from the above, we realized highly efficient spin-charge conversion via Edelstein effect occurring at the surface and interface states. More interestingly, Weyl type bulk symmetry was found to result in the charge-spin conversion where magnetization is induced by passing charge current. Furthermore we demonstrated experimentally as well as experimentally that the novel magnetic spin Hall effect could take place in Weyl antiferromagnets.
Spin Conversion Steering Committee

Otani Yoshichika

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

Institution: The University of Tokyo

2014/07/10 - 2019/03/31

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The steering committee led collaborative research between 5 research groups. We demonstrated that the spin conversion is a universal principle based on the conservation law of angular momentum, that extends to solid-liquid, solid-gas interfaces as well as solid-solid interfaces. We also showed that it is a ubiquitous phenomenon. This collaborative research project has been highly evaluated and resulted in 87 awards, including Minister of Education, Culture, Sports, Science and Technology Commendation, i.e., 3 Young Scientists and 4 Science and Technology Awards. The member principal researchers have given 15 plenary talks, and 501 invited talks at various international conferences on spintronics. Besides, we organized three international meetings to raise the international recognition of the research field for forming a base for developing an international spin conversion collaborative research. These achievements resulted in the initiative for human resource and research development.
nano spin conversion science

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

2014/07/10 - 2019/03/31
Investigation of methods for controlling physical properties by using spin currents

OTANI Yoshichika, NIIMI Yasuhiro, FUKUMA Yasuhiro

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: The University of Tokyo

2011/04/01 - 2015/03/31

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We have investigated methods for controlling magnetic properties using spin currents and obtained following results: We have succeeded in fully describing spin current properties including the anisotropic spin absorption in lateral spin valves, which enables one to elucidate intrinsic spin relaxation mechanisms in nonmagnets. We have designed the best material exhibiting large spin Hall angle based on the first principle calculation and experimentally demonstrated that Cu-Bi dilute alloys exhibited a giant spin Hall angle, charge to spin currents interconversion efficiency of about 24%. Spin torque ferromagnetic resonance experiments demonstrated that the effective damping constant of Permalloy can be modulated 20% via the spin Hall effect of platinum. We have succeeded in injecting quasi particle mediated spin currents into superconducting niobium and discovered the spin lifetime was enhanced by 400%. This achievement led to the quasi-particle mediated giant spin Hall effect.
マグノニック結晶の創製:次世代マイクロ波通信技術のための新パラダイム

大谷義近

Offer Organization: 科学技術振興機構

Category: 国際的な科学技術共同研究などの推進/戦略的国際科学技術協力推進事業/SICP/インド

2009 - 2012

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本研究交流は、双極子結合したナノ磁性体格子配列から成るマグノニック結晶のマグノニックバンド構造を詳細に調べ、情報通信・処理や論理回路技術に資する新奇かつサブテラヘルツ帯域までを見据えた広い周波数帯域のマイクロ波技術を開拓することを目的とする。具体的には、日本側はマグノニック結晶構造の設計製作と予備的な電気伝導計測を担当し、インド側は、作製されたマグノニック結晶中に、パルス磁場・光あるいはスピン注入で励起されるスピン波の時間分解計測からマグノニックバンド構造を決定することを担当する。両国の研究チームが相互補完的に取り組むことで、マグノニック結晶の設計手法が確立され、将来の情報通信要素技術の1つとしての展望が開ける。また、この高周波対応スピン波技術は、パラレル情報処理、メモリーと論理回路の間の高速データ転送、低消費電力で再構成可能な論理回路にも資するところが大きいと考えられる。
Creation and control of spin current

TAKANASHI Koki, OTANI Yoshichika, OHNO Yuzo, ONO Teruo, TANAKA Masaaki, MAEKAWA Sadamichi

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 - 2011
面内スピン角運動量移行素子におけるブリュアン光散乱法によるスピン蓄積空間分布の観測

大谷義近

Offer Organization: 科学技術振興機構

Category: 国際的な科学技術共同研究などの推進/戦略的国際科学技術協力推進事業/SICP/ドイツ

2007 - 2010
Coordination of the research on spin current and nano-hetero structures

OTANI Yoshichika, NITTA Junsaku, AKINAGA Hiroyuki, INOUE Junichiro

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: The University of Tokyo

2007 - 2010

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Supporting systems were established for promoting collaboration among 4 independent research projects ; 1. "Establishing novel methods for spin current generation and manipulation using metallic nano-structures", 2. "Electrical detection and control of spin current by using spin orbit interaction in semiconductors", 3. "Optimization of spin injection efficiency in silicon based spintronic devices", "Theory of spin injection and accumulation in nano-hetero structures". To be more precise, we have organized 1) a shared data server, 2) a video conference system, 3) periodical meetings to exchange domestic and international research information and also support for travel to attend international conferences. By using above supporting systems, we successfully obtained demonstrative results on the intrinsic origin of spin Hall effects via collaboration between theoretical and experimental groups. Moreover the discussion at the international conferences promoted successful research collaboration of French and Japanese groups for the study of the extrinsic mechanism of the spin Hall effects, leading to an important achievement.
Establishing novel methods for spin current generation and manipulation

OTANI Yoshichika, NIIMI Yasuhiro, KIMURA Takashi, TOGAWA Yoshihiko

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: The University of Tokyo

2007 - 2010

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It is indispensable to establish effective means to generate, transfer, manipulate, and detect spin currents in order to develop spintronic devices based on spin dependent transport behaviors. In this project we set following three targets concerning generation and manipulation of the spin currents ; 1) exploration of materials which exhibit large spin Hall effects ; 2) establishing a means to rotate the spin accumulation vector ; 3) establishing a method to amplify the spin accumulation using superconductors. We have accomplished almost all the three targets as planned. More precisely we first demonstrated experimentally the intrinsic nature of the spin Hall conductance in 4d and 5d transition metals, exhibiting the d-electron number dependence, and also succeeded in inducing a large extrinsic spin Hall conductance in Cu by adding Ir impurities. Secondly we have succeeded in electronic manipulation of the spin accumulation vector. We have also found the MgO interface layer drastically enhances the spin injection efficiency and the spin accumulation. Finally we have established the way to inject the spin current non-locally into superconductors. Amplification of the spin current using superconductor remained to be accomplished.
Observation of ultra-fast magnetic response by a time-resolved photoemission electron microscope

KINOSHITA Toyohiko, MURO Takayuki, OHKOUCHI Takuo, KOTSUGI Masato, OHTANI Yoshichika, OKUDA Taichi, KOBAYASHI Keisuke, MATSUSHITA Tomohiro, GUO Fungchung, OHSAWA Hitoshi, NAKAMURA Tetsuya, FUKUMOTO Keiki, ARAI Kuniaki, KIMURA Takashi, MATSUI Shinji, HARUYAMA Yuuichi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (S)

Institution: Japan Synchrotron Radiation Research Institute

2006 - 2010

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We have successfully constructed pump&probe time-resolved photoemission electron microscope system (TRPEEM) at the soft-x-ray beamline of SPring-8. Combining TRPEEM with magnetic circular dichroism effect in absorption spectra, dynamics of the vortex structure of small magnetic dots could be observed in sub nsec regime in respond to magnetic field pulse. The interaction effect between the neighboring dots was also observed. Further, dynamical observation against the electric field pulse and laser beam pulse also became possible.
Development of the rectifying device for spin dynamics using asymmetric potential

OTANI Yoshichika, KIMURA Takashi, HAMRLE Jaroslav, HARA Masahiro, NORI Franco

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (S)

Institution: The University of Tokyo

2005 - 2009

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We have performed research projects related to 3 topics below : 1. Ratchet dynamics of paired domain walls in a magnetic elliptic ring. We have established the flashing ratchet which induces the rotary motion of paired magnetic domain walls in an elliptic ring structure and the local magnetometry based on the bend resistance measurement of 2 DEG cross beneath the ring. Thereby we tried to detect the spin motive force as an example of application. However the magnitude of the induced current by the spin motive force was too small to experimentally detect by using the technique established in the present study. The detection remained as a future task. 2. Control of domain wall pinning by a switchable magnetic gate. We have demonstrated experimentally and numerically a switchable magnetic gate whereby the domain wall pinning can be magnetostatically activated by altering the magnetic alignment of paired magnetic wires from parallel to antiparallel. This magnetic gate could be a building block of the domain wall ratchet and logic devices. 3. Spin rectifying device. We have demonstrated that spin rectification from unpolarized to polarized spin currents by using the spin Hall Effects. After optimizing the spin absorption technique applied to the lateral spin valve structure, we succeeded in observing at room temperature the spin Hall Effect in a platinum nano-wire which is 1000 times larger than the effect observed in semiconductors.
MAGNETIC PROPERTIES OF REGULARLY ARRAYED NANODOTS AND THEIR APPLICATION TO ULTRA-HIGH DENSITY

KITAKAMI Osamu, FUKAMICHI Kazuaki, SHIMADA Yutaka, OKAMOTO Satoshi

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 - 2003

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In a future ultra-high density magnetic memory, the size of each memory bit will be reduced down to 10×10 nm^2, indicating that each bit consists of one nanoparticle. Therefore, the magnetization reversal process and thermal stability of each nanoparticle have to be clarified for development for the future magnetic memory. However, it has been difficult to measure the magnetic properties of such a nanoparticle because of the very poor sensitivity of 10^<-6> emu for conventional magnetometers. To overcome this difficulty, we have developed a very sensitive Hall effect method for a very small nanoparticle. The sensitivity reaches 〜 10^<-14> emu for FePt. By using this technique, we have investigated the magnetic properties and thermal stability of a single crystal L1_0-FePt (001) nanodot by patterning an well characterized epitaxial film. For the particle diameter of D_m < 20 nm, all the magnetic properties, such as the angular dependence of the irreversible switching field H_r, the magnitude of coercivity H_c, and their temperature dependences, are completely explained by the coherent rotation model (Stoner-Wohlfarth model) taking thermal relaxation into account. As the particle size D_m exceeds 20 nm, the magnetic behaviors obviously deviate from the coherent rotation model, indicating that the magnetization reversal mode changes from coherent to incoherent rotation modes. For this incoherent region, the activation energy has been evaluated to be about 10^<-12> erg regardless of the dot size, which is much smaller than the product of the anisotropy energy and dot volume but nearly equal to γδ^2 (γ: domain wall energy density, δ: wall width), suggesting that the magnetization reversal is initiated by nucleation of a reversed embryo with the dimension of the exchange length. The critical diameter D_m 〜 20 nm at which the reversal mode changes almost agrees with the critical diameter predicted by the micromagnetic theory. Based on these results, we have successfully designed the detail specifications for a prospective ultra-high density magnetic memory with the area density of 1 terabits/inch^2.
Synthesis of metal alloy particles with high magnetic surface anisotropy and development of new functions

SHIMADA Yutaka, OHTANI Yosichika, KITAKAMI Osamu

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

1997 - 1999

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Ferromagnetic materials lose their magnetic functions if their sizes decrease down to several nanometers because of emerging of the superparamagnetism. High resolution observation of magnetic domains which has been our original purpose can be achieved if synthesis of nm size ferromagnetic particles with high magnetic energy which overcomes superparamagnetism is developed. In this research developing of high energy particles by alloying and producing a high surface energy was studied. The following are the results. Co particles were produced by condensation in rare gas with stable fcc phase with the size smaller than 10nm, but hcp phase is semi-stable for these sizes. The mechanism governing this process is from the surface free energy of the particles which takes a variety of crystal shapes. To stabilize hcp phase in the particles Co-Pt particles were produced in the same way. Higher condensation of hcp phase particles were confirmed. The anisotropy energy obtained by the direct measurement of these particles is extra-ordinarily high in comparison with that of the bulk material. This strongly suggests that a surface anisotropy associated with the particle surface is taking a dominant role. Rare earth-transition metal particles were produced and the magnetism was studied. However, the particles were not chemically stable due to oxidation. The rate of instability could be reduced appreciably by overcoating the particles, but high coercivity was not attained. The possible reason for this peculiar phenomena is invasion of oxygen into the particles bodies destroying the surface smoothness which is inevitable for high surface energy. The investigation was terminated at this stage because of the difficulty mentioned above. Multilayers and granular films consisting of transition metal and oxides were synthesized and a method to evaluate the genuine surface anisotropy was developed. One of the valuable results is that the interface of Co/MgO multilayer has a very high surface anisotropy. Summarizing these results, the high energy particles which have been a purpose of the research from the start were obtained in Co-Pt system with the size down to 10nm and a high surface energy was confirmed. This provides us with a valuable suggestion that particles with higher surface energy can be synthesized by chemical reconstruction of the particle surface.
Magnetic properties of micro-structured exchange coupled bilayers

OTANI Yoshichika, KITAKAMI Osamu, SHIMADA Yutaka, FUKAMICHI Kazuaki

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

1997 - 1999

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The purpose of this study is to fabricate 3 dimensionally micro-structured exchange coupled bilayers, and to clarify a responsible mechanism for the exchange coupling field in relation to formation of the antiferromagnetic domains and walls. Amongst transition metal alloys and oxides, Cr-Al or NiO was chosen as an antiferromagnet and FeィイD220ィエD2NiィイD280ィエD2 permalloy was chosen as a ferromagnet. After the structural analyses on the grain size and crystallographic orientations between the ferromagnetic and antiferromagnetic layers with using X-ray diffractometer, atomic force microscope and electron microscope, submicron sized exchange coupled bilayers were fabricated by means of electron-bean lithography. The magnetic domain structure as well as magneto-transport properties were then carefully examined with magnetic force microscope and 4 terminal methods. For the first time, the magnetization reversal processes occurring in the sub-micron region was obtained by analyzing the anisotropy magnetoresistance and the planar Hall effects. The results were compared with the demagnetization curves calculated by micromagnetic simulation. It was found that the exchange coupling field varies proportional to the inverse of the coupling area. Furthermore the slope of the variation was found to reflect the degree of roughness at the interface which determines the strength of the net exchange coupling due to the random exchange field. From this experimental study, the exchange coupling field was shown to be controlled by adjusting the coupling area in submicron scale, which determines the antiferromagnetic domain size.
ミクロ電界蒸発による微細磁気構造の形成とその結晶成長過程の研究

島田寛, 大谷義近, 深道和明, 北上修

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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磁性ドットおよび細線を形成できる原子間力顕微鏡のプローブ表面にAuおよびCoの薄膜を形成し、プローブ-基板間にパルス電圧を印加して、ドット形成実験を行った。その結果、以下の結果が得られた。 1) 従来、基板面にドットが形成される機構は、プローブ表面の高い電界による電界蒸発の機構であるとされてきたが、ドット形成時にプローブ-基板間に流れるパルス電流を測定した結果、電界蒸発ではなく、基板表面にある薄い絶縁層が絶縁破壊することによってパルス電流が流れ、そのジュウル熱によってプローブ表面の金属が基板上にドットとして形成されることがわかった。 2) これに基づいて、電圧印加用電源の電流値を制御することによって、10〜200nmサイズのAuおよびCoのドットを形成できた。このドットは、数100箇の形成が可能であったが、磁性測定、結晶構造同定に充分な量には至っていない。プローブ表面の原子移動を促すために高温での実験を試みたが、充分な量には至らなかった。 3) 次に、数nmスケールの微細パターンを形成するために、Siの表面を酸化し、電圧を印加しつつ走査すると、巾数nmのパターンが描けることがわかった。このパターンをマスクとして、電着による磁性膜パターンの形成を試みたが、未だ成功していない。本研究の成果は以下の通りである。 1) 原子間力顕微鏡による微小体形成機構は、電界蒸発とされてきたが、パルス電流による加熱効果であることが明らかとなった。 2) 導体基板の表面を酸化することにより、微細なマスクパターンが得られることがわかった。
Magneto-optical interference effect in metalic thin films with nano-structures

OTANI Yoshichika, KITAKAMI Osamu, SHIMADA Yutaka, FUKAMICHI Kazuaki

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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The purpose of this study is to establish a novel magneto-optical diffraction technique to evaluate magnetic state in a sub-micron scale ferromagnetic substance, and to study the correlation between the magnetic state and the electronic transport properties. For this purpose, systematic studies on the 2 dimensional submicron scale dot and wire arrays were carried out by using a newly constructed magneto-optical diffractometer, a SQUID magnetometer, a high precision resistivity measurement equipment, and a magnetic force microscope. As for magneto-optics, the different orders of the diffracted light due to the array structure was found to accomodate significant magneto-optical Kerr effects. The local magnetic domain structure was successfully evaluated by taking into account the Fourier transforms of the periodical magnetic and array structures. Furthermore the diffracted light in a conical diffraction geometry was found to show Kerr effect, which provided a possible method to obtain magnetic information in the wire without an analyser. The transport experiments for the first time demonstrated that a single domain wall can be trapped in either the submicron wide wire or paired circular dots. A clear change in resistivity was found to appear in association with the domain wall nucleation and annihilation. This new phenomenon can not be explained by considering the conventional anisotropy magnetoresistance. The suppression of weak localization is suggested to be a possible mechanism. The same type of systematical studies were performed on the epitaxial Fe and Co wires, demonstrating that periodical domain walls can be stabilized in the wire. In this case, the modulation of the internal field due to the periodical domain walls are found responsible for the reduction in resistivity, that is the reduction of the surface scattering.
Development of highly sensitive magnetometer

MIYAJIMA Hideki, OTANI Yoshichika, ONO Teruo

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: Keio University

1995 - 1997

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The purpose of this study is to develop and to construct the magnetometer which can detect the magnetic moment so small as 10^<-8> emu over the temperature range from 2K to 1100K under magnetic fields up to 16 kOe in a negative and positive sense. The operational principle of the magnetometer is as follows ; A pair of field gradient coil is fixed on the pole piece of a magnet. A sample is magnetized by static fields variable in magnitude. When the gradient coil generates an alternating magnetic field on the magnetic specimen, an alternating force, proportional to both the magnetic moment of the sample and the strength of the magnitude of the field gradient, exerts on the sample. The sample rod fixed on a plate spring vibrates sympathetically at the mechanical resonance frequency determined by the spring constant and that of the alternating magnetic field, resulting the enhancement of the vibration. The amplitude of the vibration is detected by means of a search coil and, then, is converted to the inductive voltage signal proportional to the magnetic moment. The voltage is detected by using a lock-in amplifier. This new type magnetometer is call as Resonating Sample Magnetometer (RSM). A gas flow type cryostat of liquid He and a furnace with non-inductive heater are also installed in the RSM,and the temperature range from 5K to 1000K is obtained. At the present stage of March 1998, the performance of the magnetometer is as follows ; The sensitivity : 3.5*10<@D1-7@>D1 emu, the temperature range : 5K-1000K,and the magnetic field range : 0-(]SY.+-。[)16 kOe. The further improvement of the magnetometer is now carried out so as to realize the high sensitivity of the order of l0^<-8> emu. TOEI Co. Ltd.in Japan will put the commercial base RSM on the market in 1999.
強磁性微細構造膜の磁化過程の解明

大谷義近

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

1995 - 1995

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強磁性微粒子2次元格子は、高い対称性と空間的均一性を有するために磁化反転機構を調べるのに好都合である。本研究においては微細加工技術を用いて強磁性2次元格子を作製し、粒子サイズ、粒子間距離、膜厚などを適切に選択して、磁区構造、形状磁気異方性、粒子間双極子相互作用を制御して、逆磁化の核発生、成長および伝搬を系統的に調べる。微細加工された強磁性の磁化曲線は加工されていない通常の薄膜の場合と比較すると保磁力が小さく、磁化反転が急峻になることが明らかになった。この磁化反転は格子の中心に位置する微粒子列の先頭粒子から開始する事も確認された。また、磁気微粒子は一磁区磁気異方性を持ち、180°磁壁によって分割されたことも明らかになった。磁気微粒子に光を照射すると、2次元平面に並んだ周期構造のために、次数の異なる一連のブラッグ反射が得られ、その強度から微粒子内の平均的磁区構造を求める事ができることも明らかになった。
強磁性・超伝導複合構造膜の磁気・超伝導特性の研究

大谷義近

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 慶応義塾大学

1994 - 1995

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高対称性と空間的均質性を有するミクロンまたはサブミクロンスケール強磁性微粒子2次元格子は、その格子点間の双極子相互作用を通じて単磁区微粒子配列を形成し、局所磁場を引加するマイクロディバイスとなる。このような2次元格子配列を、高解像電子線リソグラフィーとスパッタリング法を用いて、超伝導Nb薄膜上に作成し、超伝導薄膜に及ぼす局所磁場の効果について研究した。格子点物質は希土類遷移金属アモルファス合金(Sm_<33>Co_<67>)及びパ-マロイ(FeNi)を用いた。格子点の大きさは2μm×2μm×200nm、格子点間距離は4Umである。磁束量子の侵入過程を調べるために、この強磁性体-超伝導体複合膜の磁化測定をベクトルSQUID磁力計と振動試料型磁力計を用いて行った。その結果、磁束量子は磁気微粒子一個を含む単位胞あたり一本の割合で、周期性をもって超伝導体内に侵入すること等が分かった。これは、微粒子配列の作る局所磁場によってNb薄膜の超伝導秩序度が周期的に変調されるため、侵入磁束を超伝導秩序の低い部分に選択的に誘導するためである。更に、着磁された磁気微粒子は外部引加磁束を吸引し磁束ガイドとして振る舞い、超伝導状態を安定化させることも解った。以上の結果について日本物理学会(1994春年会、1994秋分科会)およびInternational Conference M^2S-HTSC IVにて口頭発表したほか論文として刊行した。
Hydrogenation and Interface Magnetic Properties of Fine Ni Particles Coated with Pd

MIYAJIMA Hideki, OTANI Yoshichika

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for General Scientific Research (C)

Institution: Keio University

1994 - 1995

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The hydrogenation characteristics and the interface magnetic propirties of ferromagnetic Ni fine particles coated with paramagnetic Pd were investigated. The average size of Ni Spheres is 0.7 mum in diameter, and five samples with different weight of Pd were prepared by a chemical reduction method. The measurement results are summarized as follws ; 1) The change in a lattice constant of Pd Shells by hydrogenation depends on the thickness of the Pd shell, and the lattice constant of the Pd and a hydrogen concentration are smaller for the thinner shell. The p-x-T curves for Ni/Pd particles and bulk Pd show that the width of the plateau of Ni/Pd becomes narrpwer and the plateau pressure becomes higher than those of bulk Pd. 2) The magnetic polarization of Pd is induced by an exchange enhacement of Ni. The Magnetization of Ni/Pd particles exhibits a broad maximum in the vicinity of 80 K,and considerably increases below 50K.This magentic polarization of Pd is suppressed by hydrogenation. 3) The sample exhibit relatively large coercive force of about 130 Oe. The interface anisotropy between the Ni core and the Pd Shell is Suppressed by hydrogenation, which is independent of the thickness of Pd shell. The coercive force also decreases by hydrogenation, which implies that the coercive force is caused by the interfacek anisotropy. The narrowing of the plateau and the high plateau pressure indicate that the strain in the Pd shell is larger than in bulk Pd and impedes the hydrogenation. The magnetic polarization of Pd is induced at the interface and does not extend over the Pd shell in room temperature. The magnetic moment of the polarized Pd is estimated to be about 0.3 mug. The temperature variation of the polarized Pd is qualitatively explained by the Stoner theory that when strong exchange enhancement acts on Pd, the susceptibility of Pd is enhanced with retaining a shape of thermal variation of Pramagnetic Pd.

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