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Hikaru Nomura

Section

International Center for Synchrotron Radiation Innovation Smart

Job title

Associate Professor

Degree

博士（工学）（大阪大学）
修士（工学）（大阪大学）

researchmap

https://researchmap.jp/URlyIV1ePZ

J-GLOBAL ID

201801009087913096

Research History 8

2023/01 - Present

Tohoku University　International Center for Synchrotron Radiation Innovation Smart
2022/04 - 2022/12

大阪大学基礎工学研究科物質創成専攻　准教授
2019/04 - 2022/03

Osaka University Graduate School of Engineering Science Department of Materials Engineering Science　Associate Professor
2018/12/01 - 2019/03/31

Osaka University Graduate School of Engineering Science　Associate Professor
2008/04/01 - 2018/11/30

Osaka University Graduate School of Engineering Division of Materials and Manufacturing Science　Assistant Professor
2006/04/01 - 2008/03/31

Osaka University Graduate School of Engineering Division of Precision Science & Technology and Applied Physics　Specially Appointed Researcher
2005/10/01 - 2006/03/31

Osaka University Graduate School of Engineering　Specially Appointed Researcher
2005/06/01 - 2005/09/30

Osaka University Graduate School of Engineering Division of Precision Science & Technology and Applied Physics　Specially Appointed Researcher

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Professional Memberships 1

The Magnetics Society of Japan

Research Areas 1

Nanotechnology/Materials / Metallic materials /

Papers 52

OpenLabSPM: Bare bone package of LabVIEW-based scanning probe microscope controller

Hikaru Nomura, Junsuke Yamanishi

AIP Advances　14　(9)　2024/09/01
Publisher: AIP Publishing
DOI： 10.1063/5.0211126 　

eISSN： 2158-3226

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With the extensive proliferation of scanning probe microscopy (SPM)-related technologies, there is a growing demand for a fully customizable SPM controller. In response, we have developed an SPM controller that allows users to incorporate additional functions using LabVIEW, a graphical programming language. This controller incorporates fundamental features such as one-dimensional and two-dimensional scanning, feedback control, and slope compensation. In addition, it includes capabilities to restrict the speed of probe movement and safeguard the probe. Our system consists of a host personal computer (PC) running the Windows operating system and a National Instruments Reconfigurable Input/Output board equipped with a field programmable gate array (FPGA). The FPGA supports real-time deterministic processing, including feedback and probe protection functions, operating asynchronously from the host PC through data exchange via direct memory access first-in-first-out. The system features a graphical user interface on the Windows OS, supplemented by a character-based user interface that utilizes command strings in JavaScript object notation format. Furthermore, we provide wrappers for these commands using the Python programming language. We anticipate that our fully customizable bare born package of LabVIEW-based controller will prove beneficial for researchers utilizing SPM and those managing instruments requiring scanning and feedback control.
Hysteresis-free voltage gating of the skyrmion

Mikito Kasagawa, Soma Miki, Ken Tanaka Hashimoto, Akifumi Shimmura, Ryo Ishikawa, Yoichi Shiota, Minori Goto, Hikaru Nomura, Yoshishige Suzuki

Applied Physics Letters　2024/03/18

DOI： 10.1063/5.0192981 　
Magnetoresistance ratio in magnetic tunnel junction with silicon diffused MgO barrier

Tatsuki Watanabe, Minori Goto, Yuichiro Ando, Tsubasa Watakabe, Hikaru Nomura, Yoshishige Suzuki

Applied Physics Express　17　(1)　013001-013001　2023/12/26
Publisher: IOP Publishing
DOI： 10.35848/1882-0786/ad0ba1 　

ISSN： 1882-0778

eISSN： 1882-0786

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Abstract We demonstrated a magnetic tunnel junction (MTJ) consisting of Fe/MgO-Si-MgO/Fe. Si layer was deposited at room temperature and at 700 °C; when deposited at 700 °C, Si diffused into the MgO layer. The MTJ with silicon deposited at 700 °C attained high MR ratios of up to 38.7 and 2.9% at t_Si = 0.19 and 1.3 nm, respectively. Low-temperature measurements established that the temperature dependence of the MR ratio and resistance between MTJs with and without diffused silicon are significantly different. This behavior confirms that the Si-MgO channel acts as an impurity semiconductor in the MTJ.
Magnetization Process of Stadium-Shaped Magnetic Tunnel Junction Cells for Artificial Spin Ice

Hitoshi Kubota, Sumito Tsunegi, Kay Yakushiji, Tomohiro Taniguchi, Shingo Tamaru, Tatsuya Yamamoto, Atsushi Sugihara, Ryo Matsuura, Hikaru Nomura, Yoshishige Suzuki

IEEE Transactions on Magnetics　59　(11)　1-4　2023/11
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/tmag.2023.3291380 　

ISSN： 0018-9464

eISSN： 1941-0069
Spatial control of skyrmion stabilization energy by low-energy Ga+ ion implantation Peer-reviewed

S. Miki, K. Hashimoto, J. Cho, J. Jung, C. Y. You, R. Ishikawa, E. Tamura, H. Nomura, M. Goto, Y. Suzuki

Applied Physics Letters　122　(20)　202401　2023/05/15

DOI： 10.1063/5.0153768 　
Annealing process of Co-Fe-B based multilayers showing skyrmion Brownian motion

Minori Goto, Ryo Ishikawa, Hikaru Nomura, Yoshishige Suzuki

AIP Advances　13　(2)　025216-025216　2023/02/01
Publisher: AIP Publishing
DOI： 10.1063/9.0000582 　

eISSN： 2158-3226

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Skyrmions are topological spin textures that exhibit Brownian motion in solids. They have attracted increasing research interest in terms of realizing a device that utilizing stochastic behavior and investigating new physical phenomena. However, skyrmions that exhibit Brownian motion are sensitive to changes in magnetic properties and are easily affected by aging variation. For instance, although skyrmions appear in a sample immediately after fabrication, they sometimes disappear after few weeks. This characteristic prevents the reproducibility experiment and affects device stability. In this study, we demonstrated that aging variation can be suppressed by annealing in air for only 3 min, which is an easy and rapid method. We investigated the change in the magnetic properties by annealing and air exposure and found that the main mechanism of aging variation is oxidation of the sample surface. The magnetic properties of samples with Pt and thick SiO₂ capping were analyzed, and we demonstrated that aging variation can be suppressed by avoiding surface oxidation. Our work accelerates the research of fundamental physics regarding skyrmion Brownian motion and of device applications utilizing stochastic system.
Controlling the creation/annihilation and distribution of magnetic skyrmions by manipulating an externally applied voltage

Ryo Ishikawa, Minori Goto, Hikaru Nomura, Yoshishige Suzuki

Applied Physics Letters　121　(25)　252402-252402　2022/12/19
Publisher: AIP Publishing
DOI： 10.1063/5.0128385 　

ISSN： 0003-6951

eISSN： 1077-3118

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Magnetic skyrmions are currently gaining attention owing to their potential to act as information carriers in spintronic devices. However, conventional techniques which rely on modulating the electric current to write or manipulate information using skyrmions are not energy efficient. Therefore, in this study, a Ta/Co–Fe–B/Ta/MgO junction that hosts a skyrmion was utilized to fabricate a device to investigate the effect of applying a voltage in the direction perpendicular to the film plane. Magneto-optical Kerr effect microscopy was performed in a polar configuration to observe the difference in the perpendicular magnetic anisotropy by observing the behavior of the magnetic domain structure and the skyrmions. Our findings suggest that voltage-induced magnetic domain structure modulation and the creation/annihilation of skyrmions are both possible. Furthermore, manipulation of skyrmions was realized by utilizing repulsive magnetic dipole interaction between the voltage-created skyrmion and skyrmion, exhibiting Brownian motion, outside the top electrode. Thus, our proposed method can enable controlling the creation and annihilation of skyrmions and their positions by manipulating the externally applied voltage. These findings can advance unconventional computing fields, such as stochastic and ultra-low-power computing.
Hybrid mode atomic force microscopy of phase modulation and frequency modulation

Tatsuya Yamamoto, Masato Miyazaki, Hikaru Nomura, Yan Jun Li, Yasuhiro Sugawara

Microscopy　72　(3)　236-242　2022/11/02
Publisher: Oxford University Press (OUP)
DOI： 10.1093/jmicro/dfac057 　

ISSN： 2050-5698

eISSN： 2050-5701

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Abstract We propose hybrid phase modulation (PM)/frequency modulation (FM) atomic force microscopy (AFM) to increase the imaging speed of AFM in high-Q environments. We derive the relationship between the phase shift, the frequency shift and the tip–sample interaction force from the equation of motion for the cantilever in high-Q environments. The tip–sample conservative force is approximately given by the sum of the conservative force with respect to the phase shift in the PM mode and that with respect to the frequency shift in the FM mode. We preliminarily demonstrate that the hybrid PM/FM-AFM is a new and very promising AFM operation mode that can increase imaging speed.
Heat transfer Performance of Two-Phase Immersion Cooling by Breathing Phenomena with Different Pore Structures of Lotus Copper Peer-reviewed

M. Terada, K. Yuki, N. Unno, R. Kibushi, T. Ogushi, M. Murakami, T. Numata, T. Ide, H. Nomura

Proceedings of 2022 International Conference on Electronics Packaging (ICEP 2022)　103-104　2022/05

DOI： 10.23919/ICEP55381.2022.9795624 　
Bi-stable toggle switching in magnetic tunnel junctions using sub-nanosecond Joule heat pulses Peer-reviewed

Yuma Kaneda, Minori Goto, Tomohito Mizuno, Takekazu Yamane, Naomichi Degawa, Tsuyoshi Suzuki, Atsushi Shimura, Susumu Aoki, Junichiro Urabe, Shinji Hara, Hikaru Nomura, Yoshishige Suzuki

JAPANESE JOURNAL OF APPLIED PHYSICS　61　(4)　2022/04

DOI： 10.35848/1347-4065/ac4c4f 　

ISSN： 0021-4922

eISSN： 1347-4065
Numerical simulation of reservoir computing with magnetic nanowire lattices without inversion symmetry Peer-reviewed

K. Hon, K. Takahashi, K. Enju, M. Goto, Y. Suzuki, H. Nomura

APPLIED PHYSICS LETTERS　120　(2)　2022/01

DOI： 10.1063/5.0073465 　

ISSN： 0003-6951

eISSN： 1077-3118
Junction size dependence of the heat controlled magnetic anisotropy in magnetic tunnel junctions Peer-reviewed

Minori Goto, Reika Kobayashi, Ryota Okuno, Tomohito Mizuno, Takekazu Yamane, Naomichi Degawa, Tsuyoshi Suzuki, Atsushi Shimura, Susumu Aoki, Junichiro Urabe, Shinji Hara, Hikaru Nomura, Yoshishige Suzuki

APPLIED PHYSICS EXPRESS　15　(1)　2022/01

DOI： 10.35848/1882-0786/ac3faf 　

ISSN： 1882-0778

eISSN： 1882-0786
Uncooled sub-GHz spin bolometer driven by auto-oscillation Peer-reviewed

Minori Goto, Yuma Yamada, Atsushi Shimura, Tsuyoshi Suzuki, Naomichi Degawa, Takekazu Yamane, Susumu Aoki, Junichiro Urabe, Shinji Hara, Hikaru Nomura, Yoshishige Suzuki

Nature Communications　12　(1)　2021/12

DOI： 10.1038/s41467-020-20631-0 　

eISSN： 2041-1723
Size-Independent Drive of One-Dimensional Skyrmion Motion Using Exchange Energy Control Peer-reviewed

Soma Miki, Eiiti Tamura, Hikaru Nomura, Minori Goto, Yoshishige Suzuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　90　(11)　2021/11

DOI： 10.7566/JPSJ.90.114703 　

ISSN： 0031-9015
Enhancement of the critical heat flux of saturated pool boiling by the breathing phenomenon induced by lotus copper in combination with a grooved heat transfer surface Peer-reviewed

Risako Kibushi, Kazuhisa Yuki, Noriyuki Unno, Tetsuro Ogushi, Masaaki Murakami, Tomiyuki Numata, Takuya Ide, Hikaru Nomura

International Journal of Heat and Mass Transfer　179　121663-121663　2021/11
Publisher: Elsevier BV
DOI： 10.1016/j.ijheatmasstransfer.2021.121663 　

ISSN： 0017-9310
Stochastic skyrmion dynamics under alternating magnetic fields Peer-reviewed

Minori Goto, Hikaru Nomura, Yoshishige Suzuki

Journal of Magnetism and Magnetic Materials　536　2021/10/15

DOI： 10.1016/j.jmmm.2021.167974 　

ISSN： 0304-8853
Implementation of skyrmion cellular automaton using Brownian motion and magnetic dipole interaction Peer-reviewed

Ryo Ishikawa, Minori Goto, Hikaru Nomura, Yoshishige Suzuki

Applied Physics Letters　119　(7)　2021/08/16

DOI： 10.1063/5.0053797 　

ISSN： 0003-6951
Brownian Motion of Magnetic Skyrmions in One- and Two-Dimensional Systems Peer-reviewed

Soma Miki, Yuma Jibiki, Eiiti Tamura, Minori Goto, Mikihiko Oogane, Jaehun Cho, Ryo Ishikawa, Hikaru Nomura, Yoshishige Suzuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　90　(8)　2021/08

DOI： 10.7566/JPSJ.90.083601 　

ISSN： 0031-9015
Numerical simulation of artificial spin ice for reservoir computing Peer-reviewed

Kwan Hon, Yuki Kuwabiraki, Minori Goto, Ryoichi Nakatani, Yoshishige Suzuki, Hikaru Nomura

Applied Physics Express　14　(3)　2021/03

DOI： 10.35848/1882-0786/abdcd8 　

ISSN： 1882-0778

eISSN： 1882-0786
Physically Unclonable Functions With Voltage-Controlled Magnetic Tunnel Junctions Peer-reviewed

Yuji Tanaka, Minori Goto, Amit Kumar Shukla, Kohei Yoshikawa, Hikaru Nomura, Shinji Miwa, Shigeki Tomishima, Yoshishige Suzuki

IEEE Transactions on Magnetics　57　(2)　1-6　2021/02
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
DOI： 10.1109/tmag.2020.3042715 　

ISSN： 0018-9464

eISSN： 1941-0069
Reservoir Computing with Dipole-Coupled Nanomagnets

Hikaru Nomura, Hitoshi Kubota, Yoshishige Suzuki

Natural Computing Series　361-374　2021
Publisher: Springer Science and Business Media Deutschland GmbH
DOI： 10.1007/978-981-13-1687-6_15 　

ISSN： 1619-7127
Evaluation of air cooling performance using breathing effect of lotus wavy fins

Inoue Hiroki, Yuki Kazuhisa, kibushi Risako, Ogou Ryou, Unno Noriyuki, Ogushi Tetsuro, Murakami Masaaki, Numata Tomiyuki, Ide Takuya, Nomura Hikaru

The Proceedings of the Thermal Engineering Conference　2021　0034　2021
Publisher: The Japan Society of Mechanical Engineers
DOI： 10.1299/jsmeted.2021.0034 　

eISSN： 2424-290X

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Air cooling technology is widely used for cooling electronic devices, air conditioning devices, and engines. In order to realize a highly information-oriented society in the near future, thermal management of many related electronic devices requires a new cooling technology that exhibits excellent cooling performance with much lower power consumption. In this study, we evaluate heat transfer performance of a new air-cooling technology with lotus copper wavy fins that introduces "breathing effect". The lotus fin has unidirectional pore structure that induces gas flow passing between the fins, which enhances the heat transfer performance.
Heat Transfer Performance of Gas Cooling Technology utilizing a Passing Flow between Lotus-fins

Yuki Kazuhisa, Matano Komei, Ogou Ryou, Kibushi Risako, Unno Noriyuki, Ogushi Tetsuro, Murakami Masaaki, Takai Kio, Numata Tomiyuki, Ide Takuya, Nomura Hikaru

The Proceedings of the Thermal Engineering Conference　2020　0053　2020/10/09
Publisher: The Japan Society of Mechanical Engineers
DOI： 10.1299/jsmeted.2020.0053 　

eISSN： 2424-290X
Manipulating 1-dimensional skyrmion motion by the external magnetic field gradient Peer-reviewed

Jaehun Cho, Eiiti Tamura, Chaozhe Liu, Soma Miki, Chun Yeol You, June Seo Kim, Hikaru Nomura, Minori Goto, Ryoichi Nakatani, Yoshishige Suzuki

New Journal of Physics　22　(10)　2020/10

DOI： 10.1088/1367-2630/abbead 　

ISSN： 1367-2630
Enhanced electric control of magnetic anisotropy via high thermal resistance capping layers in magnetic tunnel junctions Peer-reviewed

Ryota Okuno, Yuma Yamada, Minori Goto, Tomohito Mizuno, Takekazu Yamane, Naomichi Degawa, Tsuyoshi Suzuki, Atsushi Shimura, Susumu Aoki, Junichiro Urabe, Shinji Hara, Hikaru Nomura, Yoshishige Suzuki

JOURNAL OF PHYSICS-CONDENSED MATTER　32　(38)　2020/09

DOI： 10.1088/1361-648X/ab94f3 　

ISSN： 0953-8984

eISSN： 1361-648X
Skyrmion Brownian circuit implemented in continuous ferromagnetic thin film Peer-reviewed

Yuma Jibiki, Minori Goto, Eiiti Tamura, Jaehun Cho, Soma Miki, Ryo Ishikawa, Hikaru Nomura, Titiksha Srivastava, Willy Lim, Stephane Auffret, Claire Baraduc, Helene Bea, Yoshishige Suzuki

Applied Physics Letters　117　(8)　2020/08/24

DOI： 10.1063/5.0011105 　

ISSN： 0003-6951
Reservoir computing with two-bit input task using dipole-coupled nanomagnet array Peer-reviewed

Hikaru Nomura, Kazuki Tsujimoto, Minori Goto, Naoki Samura, Ryoichi Nakatani, Yoshishige Suzuki

Japanese Journal of Applied Physics　59　(SE)　SEEG02-SEEG02　2020/04/01
Publisher: IOP Publishing
DOI： 10.7567/1347-4065/ab4f0f 　

ISSN： 0021-4922

eISSN： 1347-4065
Thermal management of automotive SiC-based on-board inverter with 500 W/cm² in heat flux, and Two-phase immersion cooling by breathing phenomenon spontaneously induced by lotus porous copper jointed onto a grooved heat transfer surface Peer-reviewed

Kazuhisa YUKI, Risako KIBUSHI, Rikako TSUJI, Kio TAKAI, Noriyuki UNNO, Tetsuro OGUSHI, Masaaki MURAKAMI, Tomiyuki NUMATA, Hikaru NOMURA, Takuya IDE

Journal of Thermal Science and Technology　15　(1)　JTST0012-JTST0012　2020

DOI： 10.1299/jtst.2020jtst0012 　

ISSN： 1880-5566

eISSN： 1880-5566
Randomly generated node-state-update procedure for dipole-coupled magnetic reservoir computing with voltage control of the magnetism Peer-reviewed

Hikaru Nomura, Taishi Furuta, Kazuki Tsujimoto, Yuki Kuwabiraki, Naoki Samura, Eiiti Tamura, Minori Goto, Ryoichi Nakatani, Hitoshi Kubota, Yoshishige Suzuki

Journal of Physics D: Applied Physics　53　(9)　094001-094001　2020
Publisher: IOP Publishing
DOI： 10.1088/1361-6463/ab5a27 　

ISSN： 0022-3727

eISSN： 1361-6463
Heat Transfer Performance of Lotus-fin Gas Cooling utilizing a Passing Flow

Matano Komei, Yuki Kazuhisa, Kibushi Risako, Unno Noriyuki, Ogushi Tetsuro, Murakami Masaaki, Numata Tomiyuki, Ide Takuya, Nomura Hikaru

The Proceedings of the Thermal Engineering Conference　2019　0131　2019
Publisher: The Japan Society of Mechanical Engineers
DOI： 10.1299/jsmeted.2019.0131 　

eISSN： 2424-290X
Reservoir computing with dipole-coupled nanomagnets Peer-reviewed

Hikaru Nomura, Taishi Furuta, Kazuki Tsujimoto, Yuki Kuwabiraki, Ferdinand Peper, Eiiti Tamura, Shinji Miwa, Minori Goto, Ryoichi Nakatani, Yoshishige Suzuki

Japanese Journal of Applied Physics　58　(7)　070901-070901　2019
Publisher: IOP Publishing
DOI： 10.7567/1347-4065/ab2406 　

ISSN： 0021-4922

eISSN： 1347-4065
Stable contrast mode on TiO2(110) surface with metal-coated tips using AFM Peer-reviewed

Yan Jun Li, Huanfei Wen, Quanzhen Zhang, Yuuki Adachi, Eiji Arima, Yukinori Kinoshita, Hikaru Nomura, Zongmin Ma, Lili Kou, Yoshihiro Tsukuda, Yoshitaka Naitoh, Yasuhiro Sugawara, Rui Xu, Zhihai Cheng

Ultramicroscopy　191　51-55　2018/08/01
Publisher: Elsevier B.V.
DOI： 10.1016/j.ultramic.2018.04.003 　

ISSN： 1879-2723 0304-3991
Effect of Groove Size on Heat Transfer Performance of Two-phase Immersion Cooling with Lotus Copper Jointed onto a Grooved Heat Transfer Surface

Tsuji Rikako, Yuki Kazuhisa, Takai Kio, UNNO Noriyuki, Kibushi Risako, Ide Takuya, Ogushi Tetsuro, Murakami Masaaki, Numata Tomiyuki, Nomura Hikaru

The Proceedings of the Thermal Engineering Conference　2018　0187　2018
Publisher: The Japan Society of Mechanical Engineers
DOI： 10.1299/jsmeted.2018.0187 　

eISSN： 2424-290X

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This paper describes boiling heat transfer performance of a lotus-type porous copper plate attached onto a grooved heat transfer surface in a saturated pool. The boiling heat transfer experiments are conducted under atmospheric conditions using water as cooling liquid. The lotus copper has uni-directional pore structure in a perpendicular direction to the heated surface, and the average pore diameter and the thickness are 0.49 mm and 2.0 mm, respectively. The boiling curves prove that the utilization of larger size of groove leads to the improvement of the critical heat flux. The critical heat flux in the case of the groove width of 1.0 mm reach is 517 W/cm².
Controlling operation timing and data flow direction between nanomagnet logic elements with spatially uniform clock fields Peer-reviewed

Hikaru Nomura, Naomichi Yoshioka, Soichiro Miura, Ryoichi Nakatani

Applied Physics Express　10　(12)　123004-123004　2017/12
Publisher: IOP Publishing
DOI： 10.7567/APEX.10.123004 　

ISSN： 1882-0778

eISSN： 1882-0786
Switching of Perpendicular Exchange Bias in Pt/Co/Pt/alpha-Cr2O3/Pt Layered Structure Using Magneto-electric Effect Peer-reviewed

Kentaro Toyoki, Yu Shiratsuchi, Atsushi Kobane, Shotaro Harimoto, Satoshi Onoue, Hikaru Nomura, Ryoichi Nakatani

Journal of Applied Physics　117　17D902　2016/05
Growth models of coexisting p(2 x 1) and c(6 x 2) phases on an oxygen-terminated Cu(110) surface studied by noncontact atomic force microscopy at 78 K Peer-reviewed

Yan Jun Li, Seung Hwan Lee, Yukinori Kinoshita, Zong Min Ma, Huanfei Wen, Hikaru Nomura, Yoshitaka Naitoh, Yasuhiro Sugawara

Nanotechnology　27　(20)　205702-205702　2016/04/07
Publisher: Institute of Physics Publishing
DOI： 10.1088/0957-4484/27/20/205702 　

ISSN： 1361-6528 0957-4484

eISSN： 1361-6528
Magnetic force microscopy using tip magnetization modulated by ferromagnetic resonance Peer-reviewed

Eiji Arima, Yoshitaka Naitoh, Yan Jun Li, Satoru Yoshimura, Hitoshi Saito, Hikaru Nomura, Ryoichi Nakatani, Yasuhiro Sugawara

Nanotechnology　26　(12)　125701-125701　2015/03/27
Publisher: Institute of Physics Publishing
DOI： 10.1088/0957-4484/26/12/125701 　

ISSN： 1361-6528 0957-4484

eISSN： 1361-6528
Data input and output method for three dimensional array of magnetic bit with magnetic force microscopy

IWAKI Keisuke, WAKASA Ryouki, NOMURA Hikaru, Nakatani Ryoichi

ITE Technical Report　39　19-22　2015
Publisher: The Institute of Image Information and Television Engineers
DOI： 10.11485/itetr.39.37.0_19 　

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A magnetic quantum cellular automata (MQCA) is one of a promised candidate for future ultra-low power devices. Recently, the research for MQCA is shifted from two dimensional MQCA to three dimensional MQCA. To accelerate basic researches of 3D-MQCA, it is necessary to develop a digital information input method. Here, we propose and demonstrate magnetization manipulation method for 3D-MQCA with magnetic force microscopy. With this method, we can manipulate an individual magnetic layer of nano-dots. This method will accelerate basic researches of magnetic devices with magnetic multilayer such as 3D-MQCA.
Switching of perpendicular exchange bias in Pt/Co/Pt/alpha-Cr2O3/Pt layered structure using magneto-electric effect Peer-reviewed

Kentaro Toyoki, Yu Shiratsuchi, Atsushi Kobane, Shotaro Harimoto, Satoshi Onoue, Hikaru Nomura, Ryoichi Nakatani

Journal of Applied Physics　117　(17)　17D902-17D902　2015/01
Equilibrium surface magnetization of alpha-Cr2O3 studied through interfacial chromium magnetization in Co/alpha-Cr2O3 layered structures Peer-reviewed

Kentaro Toyoki, Yu Shiratsuchi, Tetsuya Nakamura, Chiharu Mitsumata, Shotaro Harimoto, Yuichiro Takechi, Takashi Nishimura, Hikaru Nomura, Ryoichi Nakatani

APPLIED PHYSICS EXPRESS　7　(11)　2014/11

DOI： 10.7567/APEX.7.114201 　

ISSN： 1882-0778

eISSN： 1882-0786
Magneto-electric effect of α-Cr₂O₃(0001) thin film on perpendicular exchange bias and influence of Pt spacer layer

Shiratsuchi Yu, Toyoki Kentaro, Nakamura Tetsuya, Suzuki Motohiro, Harimoto Shotaro, Onoue Satoshi, Nomura Hikaru, Mitsumata Chiharu, Nakatani Ryoichi

JSAP Annual Meetings Extended Abstracts　2014.2　1831-1831　2014/09/01
Publisher: The Japan Society of Applied Physics
DOI： 10.11470/jsapmeeting.2014.2.0_1831 　

eISSN： 2436-7613
Clock field in arrayed magnetic logic gates with a magnetic force microscope tip Peer-reviewed

H. Nomura, Y. Imanaga, Y. Hiratsuka, R. Nakatani

Journal of Physics: Conference Series　379　(1)　2012
Publisher: Institute of Physics Publishing
DOI： 10.1088/1742-6596/379/1/012019 　

ISSN： 1742-6596 1742-6588
Switching surface polarization of atomic force microscopy probe utilizing photoisomerization of photochromic molecules Peer-reviewed

Yoshihiro Aburaya, Hikaru Nomura, Masami Kageshima, Yoshitaka Naitoh, Yan Jun Li, Yasuhiro Sugawara

JOURNAL OF APPLIED PHYSICS　109　(6)　2011/03

DOI： 10.1063/1.3552926 　

ISSN： 0021-8979
NAND/NOR logical operation of a magnetic logic gate with canted clock-field Peer-reviewed

Hikaru Nomura, Ryoichi Nakatani

Applied Physics Express　4　(1)　13004　2011/01

DOI： 10.1143/APEX.4.013004 　

ISSN： 1882-0778 1882-0786
Effect of surface stress around the SA step of Si(001) on the dimer structure determined by noncontact atomic force microscopy at 5K Peer-reviewed

Yoshitaka Naitoh, Yan Jun Li, Hikaru Nomura, Masami Kageshima, Yasuhiro Sugawara

Journal of the Physical Society of Japan　79　(1)　2010/01

DOI： 10.1143/JPSJ.79.013601 　

ISSN： 0031-9015 1347-4073
Interface Magnetism of Au/Co/Cr2O3(0001) Epitaxial Film with Perpendicular Magnetic Anisotropy and Perpendicular Exchange Bias Peer-reviewed

Noboru Iwata, Yoshiteru Murakami, Akira Takahashi, Hikaru Nomura, Ryoichi Nakatani

Journal of the Magnetics Society of Japan　2009/06
Development of a magnetic force microscopy for magnetically soft materials Peer-reviewed

Hikaru Nomura, Tatsuro Nagayama, Daisuke Yokota, Ryoichi Nakatani

Journal of Physics: Conference Series　165　2009
Publisher: Institute of Physics Publishing
DOI： 10.1088/1742-6596/165/1/012036 　

ISSN： 1742-6596 1742-6588
Magnetic logic devices composed of permalloy dots Peer-reviewed

Ryoichi Nakatani, Hikaru Nomura, Yasushi Endo

Journal of Physics: Conference Series　165　2009
Publisher: Institute of Physics Publishing
DOI： 10.1088/1742-6596/165/1/012030 　

ISSN： 1742-6596 1742-6588
High-Speed phase-modulation atomic force microscopy in constant-amplitude mode capable of simultaneous measurement of topography and energy dissipation Peer-reviewed

Yan Jun Li, Naritaka Kobayashi, Hikaru Nomura, Yoshitaka Naitoh, Masami Kageshima, Yasuhiro Sugawara

Japanese Journal of Applied Physics　47　(7)　6121-6124　2008/07/18

DOI： 10.1143/JJAP.47.6121 　

ISSN： 0021-4922 1347-4065
Force microscopy imaging of rest atom on Si(111)7x7 surface under strong tip-surface interaction Peer-reviewed

Yoshitaka Naitoh, Kohji Momotani, Hikaru Nomura, Yan Jun Li, Masami Kageshima, Yasuhiro Sugawara

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　76　(3)　2007/03

DOI： 10.1143/JPSJ.76.033601 　

ISSN： 0031-9015
Dissipative force modulation Kelvin probe force microscopy applying doubled frequency ac bias voltage Peer-reviewed

Hikaru Nomura, Kenichiro Kawasaki, Takuma Chikamoto, Yan Jun Li, Yoshitaka Naitoh, Masami Kageshima, Yasuhiro Sugawara

Applied Physics Letters　90　(3)　2007

DOI： 10.1063/1.2432281 　

ISSN： 0003-6951
Origin of p (2 × 1) Phase on Si(001) by Noncontact Atomic Force Microscopy at 5 K

Yan Jun Li, Hikaru Nomura, Naoyuki Ozaki, Yoshitaka Naitoh, Masami Kageshima, Yasuhiro Sugawara, Chris Hobbs, Lev Kantorovich

Physical Review Letters　96　(10)　2006/03/16
Publisher: American Physical Society
DOI： 10.1103/physrevlett.96.106104 　

ISSN： 1079-7114 0031-9007

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Misc. 7

Magnetic quantum cellular automata circuit : MQCA shift register

NOMURA Hikaru, MORITA Akihiro, NAKATANI Ryoichi

IEICE technical report. Magnetic recording　113　(407)　35-40　2014/01/24
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN： 0913-5685

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Magnetic quantum cellular automata (MQCA) is one of a logic-in-memory devices. The MQCA is composed of nano-magnets. Binary state of "0" and "1" are stored as a direction of a magnetization of the nano-magnets, and a logic operation is executed via magneto-static interaction between the nano-magnets. In general, a logic operation in MQCA is executed after an elimination of binary-state of nano-magnets. However, with this method, it is difficult to define a data flow direction without using a localized magnetic field. Here we introduce an MQCA element which can define a data flow direction by a shape of the element. We propose a data-dot and buffer-dot that easy axes make an angle of 45 degrees. We also propose a clock field for these dots. And with these methods, we demonstrate MQCA shift registers by micro-magnetics simulation. By combining these methods with general MQCA logic gate, a high-functional MQCA circuit will be realized in near future.
Magnetic quantum cellular automata circuit : MQCA shift register

38　(3)　35-40　2014/01
Publisher: 映像情報メディア学会
ISSN： 1342-6893
Magnetization manipulation method for magnetic nanodots with magnetic force microscopy

MAEHARA Kei, TOYOKI Kentaro, YOKOTA Daisuke, NOMURA Hikaru, NAKATANI Ryoichi

IEICE technical report. Magnetic recording　112　(416)　21-24　2013/01/18
Publisher: The Institute of Electronics, Information and Communication Engineers

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Magnetic force microscopy (MFM) is a member of scanning probe microscopy family. The MFM is a powerful tool, which can measure and manipulate a magnetization of a sample surface by scanning a magnetic tip. However, a threshold position of the magnetic tip for the magnetization manipulation has not clarified yet. Here, we propose a vertical magnetization manipulation method, and clarify the threshold magnetic tip position for magnetization manipulation. By selecting the magnetic tip position, we can create single-domain state, clockwise vortex state and counterclockwise vortex state on an elliptic nanodot.
Kelvin Probe Force Microscopy and Its Application to Evaluation of Thin Film Growth

SUGAWARA Yasuhiro, NOMURA Hikaru, NAITOH Yoshitaka, LI Yan Jun

47　(1)　18-21　2012/03/30
Publisher: 日本顕微鏡学会
ISSN： 1349-0958
NAND/NOR Logical Operation with Magnetic Logic Gate

NOMURA H., NAKATANI R.

Magnetics Japan　6　(1)　29-36　2011/02/01
Publisher: 日本磁気学会
ISSN： 1880-7208
New magnetic logic devices

63　(4)　52-56　2011
Publisher: 生産技術振興協会
ISSN： 0387-2211
Evaluation of Domain-Wall's behavior in Ni-Fe magnetic nanowire with constriction

NAGAYAMA Tatsuro, NOMURA Hikaru, ENDO Yasushi, NAKATANI Ryoichi

IEICE technical report　108　(380)　17-21　2009/01/08
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN： 0913-5685

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In this study, we investigate the magnetization switching process of the Ni-20at%Fe nanowire with constriction through the motion of the domain wall. The motions of the domain wall in the nanowire have been clarified by Magnetic field sweeping magnetic force microscopy (MFS-MFM). MFS-MFM is directly measure the motion of the domain structure of the sample, without a disturbance of the magnetic structure of the sample by MFM tip stray field. The magnetization switching processes ware found to be strongly dependent on the thickness and the geometry of the nanowire.

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Books and Other Publications 2

Practical Programming by Fortran90/95

Kiyokazu Yasuda

Osaka University Press　2014/03
Fortran90/95による実践プログラミング

安田清和他

大阪大学出版会　2014/03

ISBN: 9784872594737

Industrial Property Rights 4

演算装置

野村光, 鈴木義茂, 地引勇磨, 後藤穣

Property Type: Patent
情報処理装置及び情報処理方法

野村光, 鈴木義茂, 田村英一, 三輪真嗣, 後藤穣, F. Peper

Property Type: Patent
情報処理装置及び情報処理方法

野村光, 鈴木義茂, 田村英一, 三輪真嗣, 後藤穣, F. Peper

Property Type: Patent
磁性演算素子

野村光, 中谷亮一

Property Type: Patent

Research Projects 10

Development of artificial intelligence hardware using magnetic tunnel junctions

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: National Institute of Advanced Industrial Science and Technology

2020/08/31 - 2025/03/31
Magnetoelectric effect based magnetization reversal towards high-density magnetic storage

Nakatani Ryoichi

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: Osaka University

2016/04/01 - 2020/03/31

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In this project, we focused on the magnetoelectric induced antiferromagnetic spin/domain reversal and the elucidation of the microscopic mechanism toward the high-density magnetic storage as a final goal. Starting from the relalization of the magnetoelectric effect in Cr2O3 thin film, we developed this to the following main results; (1) Realization of isothermal and reversible switching of ferromagnetic magnetization, which is a marker of the magnetoelectric antiferromagnetic domain/spin, and elucidation of the switching energy condition, (2) Switching process of the antiferromagnetic domain driven by the magnetoelectric effect, (3) Mechanism of high perpendicular exchange bias in ferromagnetic layer/Cr2O3 layer stacking, (4) Reduction of Cr2O3 layer thickness exhibitign the magnetoelectirc effect
探索・分析する自然言語系AIシステムを用いた知見・教訓の利活用に関する研究 Other

Offer Organization: 宇宙航空研究開発機構

2020 -
Electric-field driven antiferromagnetic domain dynamics

Shiratsuchi Yu

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: Osaka University

2016/04/01 - 2019/03/31

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Magnetic domain and magnetization reversal process of the magnetoelectric antiferromagmet, Cr2O3 was investigated. In particular, magnetoelectric (ME, static magnetic field + dynamic electric field) driven reversal was focused. Main findings of this work are (1) Magnetization reversal was proceeded by nucleation of the reversed magnetic domain and propagation of the magnetic domain wall, similar to the ordinal ferromagnet. (2) By using the pulsed voltage as a driving force, we clarified the antiferromagnetic domain wall velocity quantitatively.
探索・分析する自然言語系AIシステムを用いた知見・教訓の利活用に関する研究 Other

Offer Organization: 宇宙航空研究開発機構

2019 -
フレキシブルスピンデバイスを用いた完全無電力IoTレジスタ・論理演算素子の創製 Collaborative (industry/university)

Offer Organization: 文部科学省

2019 -
Study of visualization of nano-magnetic dynamics and the development of the experimental techniques using synchrotron radiation

Nakamura Tetsuya

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: Japan Synchrotron Radiation Research Institute

2015/04/01 - 2018/03/31

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We have studied the synchrotron X-ray magnetic circular dichroism (XMCD) measurement techniques using the nano-focused X-ray beam and the application to magnetic thins films. The time resolved XMCD signals have been successfully observed for the local area of about 100 nm in a Co/Pt multilayered film, where the applied magnetic fields were generated and synchronized with the pulsed X-rays. As a further advanced technical challenge, we have developed a scanning probe microscope (SPM) measurement technique combined with the synchrotron soft X-rays, which is so called SR-SPM. In the SR-SPM apparatus equipped with an X-ray focusing unit using a Fresnel zone plate, the higher density soft X-ray beam of about 1000 times compared to the previous studies irradiates the sample surface just below the SPM needle. XMCD signals from permalloy dots of the magnetite has been successfully recorded using the SR-SPM system with the special resolution of about 70 nm.
Logic operation with three dimensional magnetic cellular automata

Nomura Hikaru

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: Osaka University

2014/04/01 - 2016/03/31

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In this study, we proposed NAND/NOR gates based on a three dimensional magnetic quantum cellular automata (3D-MQCA). The 3D-MQCA NAND/NOR gates were composed of nanodots with magnetic multilayer. The MQCA gates have advantage of information non-volatility and high resistivity to an ionized particle. In previous studies, MQCA NAND/NOR gates were only demonstrated with two dimensional structures. Therefore, a number of input/output was limited. With 3D-MQCA, we can increase the number of input/output and create a more functional gate in a near future. To demonstrate the 3D-MQCA gates, we developed a reading and writing method for an individual magnetic layer in nanodots by magnetic force microscopy (MFM). This method will become a powerful tool for basic researches with magnetic multilayer structure.
Pependicular magnetic anisotropy at metarl/insulater interface toward spintronics devicies with low power consumption

NAKATANI Ryoichi, SHIRATSUCHI Yu, NOMURA Hikaru

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: Osaka University

2012/04/01 - 2015/03/31

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Toward spintronic devices with low power consumption, we investigated the interface magnetic anisotropy of metallic ferromagnet (FM)/oxide antiferromagnet stacked film. In particular we focused on the microscopic mechanism and the electric-field control of the exchange anisotropy at the FM/Cr2O3 interface. Main results are (1) the exchange anisotropy energy density changes with the ferromagnetic layer composition and the crystalline quality of the Cr2O3 layer, (2) the new type of temperature dependence of exchange anisotropy, i.e. the high temperature regeneration was found in the Pt/Co/0.2-nm-thick Pt/Cr2O3/Pt stacked film, (3) the interfacial uncompensated Cr spins are un-reversed with the FM spin reversal. We also developed the electric-field induced switching of the exchange anisotropy based on the magneto-electric effect of Cr2O3.
Domain wall propagation condition in nanowire under a localized magnetic field

NOMURA Hikaru

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Young Scientists (B)

Institution: Osaka University

2010 - 2011

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Here, we propose a programmable pinning site for racetrack memory. In racetrack memory, a notch structure is used to control domain wall propagation. However, with the notch structure, a condition of domain wall propagation is fixed at the design stage. With nanomagnets adjacent to a nanowire, the condition of domain wall propagation shows different value associated with combination of magnetization directions of the nanomagnets.

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Teaching Experience 16

A Door to Academia
Introduction to magnetism and spintronics
Advanced magnetism and spintronics
Solids in Nano-scale
Introduction to Engineering Science
Materials Science and Engineering Seminar I
Materials Science and Engineering Seminar II
Mechanics II
A Door to Academia
Introduction to magnetism and spintronics
Advanced magnetism and spintronics
Solids in Nano-scale
Materials Science and Engineering Seminar I
Materials Science and Engineering Seminar II
Mechanics II
Physics Experiments

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