Hiroaki Sukegawa
Group Leader, Spintronics Group,
Research Center for Magnetic and Spintronic Materials
Email: SUKEGAWA.Hiroaki[at]nims.go.jp


SHORT BIOGRAPHY
Hiroaki Sukegawa received his Ph.D. in materials science from Tohoku University in 2007 and has been a Researcher in (2007-2014), Senior Researcher (2014-2018), Principal Researcher (2018-2023), and Group Leader (2023-present) at NIMS.
His research interests are in the development of magnetic thin films/nanostructures and spintronic devices. Especially, he has been developing new materials and structures of magnetic tunnel junctions (MTJs) for more than 20 years. He and his Gr members developed spinel oxide thin films (e.g. MgAl₂O₄ [Details] and MgGa₂O₄ [Details]) as alternative MTJ barriers exhibiting the giant tunnel magnetoresistance (TMR) effect since 2009. In 2023, he and his Gr members successfully demonstrated the world record TMR ratio of 631% at room temperature for the first time in 15 years [Details].

The figure below shows the history of room temperature TMR ratios for each barrier material. The NIMS Spintronics Group holds the largest values for MgO barrier, spinel barrier, and gallium spinel barrier (as of 2025).


(Fugure) Trends in room temperature TMR ratio and reported values of Spintronics Group


EDUCATION

Dr. Eng. Materials Science, Tohoku Univeristy, 2007

M.S. Materials Science, Tohoku Univeristy, 2004

B.S. Materials Science, Tohoku University, 2002

PROFESSIONAL EXPERIENCE

2023.4 - present: Group Leader, National Institute for Materials Science

2018.4 - 2023.3: Principal researcher, National Institute for Materials Science

2014.4 - 2018.3: Senior researcher, National Institute for Materials Science

2007.4 - 2014.3: Researcher, National Institute for Materials Science

2006.4－2007.3: Fellowships from Japan Society for Promotion of Science (DC2)

RESEARCH INTEREST

Spintronics

Microfabrication of Magnetic Thin Films

Magnetic tunnel junction

Co-based Heusler alloys

Spinel barrier

Recent Publications, Presentations and Patents

https://samurai.nims.go.jp/profiles/sukegawa_hiroaki/publications

Google Scholar

Selected Publications All publications (ResearchGate)

1. Rombang Rizky Sihombing, Thomas Scheike, Jun Uzuhashi, Tadakatsu Ohkubo, Zhenchao Wen, Seiji Mitani, and Hiroaki Sukegawa (corresponding author),
   "Enhanced tunnel magnetoresistance of Fe/MgGa₂O₄/Fe(001) magnetic tunnel junctions by interface-tuning with atomic scale MgO insertion layers"
   Appl. Phys. Lett. 126, 022407-1~7 (2025).
   Selected as Editor's Pick
   Open access


2. Explanation in Research page
   Jieyuan Song (corresponding author), Thomas Scheike, Cong He, Zhenchao Wen, Tadakatsu Ohkubo, Kwangseok Kim, Hiroaki Sukegawa (corresponding author), and Seiji Mitani,
   "Incommensurate superlattice modulation surviving down to an atomic scale in sputter-deposited Co/Pt(111) epitaxial multilayered films"
   APL Mater. 12, 101120-1~7 (2024).
   Open access
   


3. Cong He, Keisuke Masuda, Jieyuan Song, Thomas Scheike, Zhenchao Wen; Yoshio Miura, Tadakatsu Ohkubo, Kazuhiro Hono, Seiji Mitani, and Hiroaki Sukegawa,
   "Nano-crystal domains in Co-based fcc(111) epitaxial magnetic junctions and their impact on tunnel magnetoresistance"
   Acta Mater. 261, 119394-1~14 (2023).


4. Explanation in Research page
   Thomas Scheike, Zhenchao Wen, Hiroaki Sukegawa (corresponding author), and Seiji Mitani,
   "631% room temperature tunnel magnetoresistance with large oscillation effect in CoFe/MgO/CoFe(001) junctions"
   Appl. Phys. Lett. 122, 112404-1~6 (2023).
   Selected as Featured Article
   Open access
   


5. Thomas Scheike, Zhenchao Wen, Hiroaki Sukegawa (corresponding author), and Seiji Mitani,
   "Enhanced tunnel magnetoresistance in Fe/Mg₄Al-Ox/Fe(001) magnetic tunnel junctions"
   Appl. Phys. Lett. 120, 032404-1~4 (2022).
   Selected as Editor's Pick
   Open access


6. Muftah Al-Mahdawi, Qingyi Xiang, Yoshio Miura, Mohamed Belmoubarik, Keisuke Masuda, Shinya Kasai, Hiroaki Sukegawa, and Seiji Mitani,
   "Quantum-well tunneling anisotropic magnetoresistance above room temperature"
   Phys. Rev. B 103, L180408-1~6 (2021).


7. Thomas Scheike, Qingyi Xiang, Zhenchao Wen, Hiroaki Sukegawa (corresponding author), Tadakatsu Ohkubo, Kazuhiro Hono, and Seiji Mitani,
   "Exceeding 400% tunnel magnetoresistance at room temperature in epitaxial Fe/MgO/Fe(001) spin-valve-type magnetic tunnel junctions"
   Appl. Phys. Lett. 118, 042411-1~6 (2021).
   Selected as Featured Article
   Selected as Scilight


8. Q. Y. Xiang, H. Sukegawa, M. Belmoubarik, M. Al-Mahdawi, T. Scheike, S. Kasai, Y. Miura, and S. Mitani,
   "Realizing Room-Temperature Resonant Tunnel Magnetoresistance in Cr/Fe/MgAl₂O₄ Quasi-Quantum Well Structures"
   Adv. Sci. 6, 1901438-1~7 (2019).


9. Ikhtiar, Hiroaki Sukegawa (corresponding author), Xiandong Xu, Mohamed Belmoubarik, Hwachol Lee, Shinya Kasai, and Kazuhiro Hono,
   "Giant tunnel magnetoresistance in polycrystalline magnetic tunnel junctions with highly-textured MgAl₂O₄(001) based barriers"
   Appl. Phys. Lett. 112, 022408-1~5 (2018).
   Selected as Featured article


10. Hiroaki Sukegawa, Yushi Kato, Mohamed Belmoubarik, P.-H. Cheng, Tadaomi Daibou, Naoharu Shimomura, Yuuzo Kamiguchi, Junichi Ito, Hiroaki Yoda, Tadakatsu Ohkubo, Seiji Mitani, and Kazuhiro Hono,
    "MgGa₂O₄ spinel barrier for magnetic tunnel junctions: Coherent tunneling and low barrier height"
    Appl. Phys. Lett. 110, 122404-1~5 (2017).
    Selected as AIP in the news


11. Hiroaki Sukegawa, Jason Paul Hadorn, Zhenchao Wen, Tadakatsu Ohkubo, Seiji Mitani, and Kazuhiro Hono,
    "Perpendicular magnetic anisotropy at lattice-matched Co₂FeAl/MgAl₂O₄(001) epitaxial interfaces"
    Appl. Phys. Lett. 110, 112403-1~4 (2017).


12. Thomas Scheike, Hiroaki Sukegawa (corresponding author), Koichiro Inomata, Tadakatsu Ohkubo, Kazuhiro Hono, and Seiji Mitani,
    "Chemical ordering and large tunnel magnetoresistance in Co₂FeAl/MgAl₂O₄/Co₂FeAl(001) junctions"
    Appl. Phys. Express 9, 053004-1~4 (2016).
    Selected as Spotlights2016


13. Mohamed Belmoubarik, Hiroaki Sukegawa (corresponding author), Tadakatsu Ohkubo, Seiji Mitani, and Kazuhiro Hono,
    "MgAl₂O₄(001) based magnetic tunnel junctions made by direct sputtering of a sintered spinel target"
    Appl. Phys. Lett. 108, 132404-1~5 (2016).
    Selected as APL Editor's pick


14. Zhenchao Wen, Hiroaki Sukegawa, Takao Furubayashi, Jungwoo Koo, Koichiro Inomata, Seiji Mitani, Jason Paul Hadorn, Tadakatsu Ohkubo, and Kazuhiro Hono,
    "A 4-Fold-Symmetry Hexagonal Ruthenium for Magnetic Heterostructures Exhibiting Enhanced Perpendicular Magnetic Anisotropy and Tunnel Magnetoresistance"
    Adv. Mater. 26, 6483-6490 (2014).


15. Hiroaki Sukegawa, Yoshio Miura, Shingo Muramoto, Seiji Mitani, Tomohiko Niizeki, Tadakatsu Ohkubo, Kazutaka Abe, Masafumi Shirai, Koichiro Inomata, and Kazuhiro Hono,
    "Enhanced tunnel magnetoresistance in a spinel oxide barrier with cation site disorder",
    Phys. Rev. B 86, 184401-1~5 (2012).


16. Hiroaki Sukegawa, Huixin Xiu, Tadakatsu Ohkubo, Takao Furubayashi, Tomohiko Niizeki, Wenhong Wang, Shinya Kasai, Seiji Mitani, Koichiro Inomata, and Kazuhiro Hono,
    "Tunnel Magnetoresistance with Improved Bias Voltage Dependence in Lattice-Matched Fe/Spinel MgAl₂O₄/Fe(001) Junctions"
    Appl. Phys. Lett. 96, 212505-1~3 (2010).


17. R. Shan, H. Sukegawa, W. H. Wang, M. Kodzuka, T. Furubayashi, T. Ohkubo, S. Mitani, K. Inomata, and K. Hono,
    "Demonstration of Half-Metallicity in Fermi-Level-Tuned Heusler Alloy Co₂FeAl_0.5Si_0.5 at Room Temperature"
    Phys. Rev. Lett. 102, 246601-1~4 (2009).


18. H. Sukegawa, S. Nakamura, A. Hirohata, N. Tezuka and K. Inomata,
    "Significant Magnetoresistance Enhancement Due to a Cotunneling Process in a Double Tunnel Junction with Single Discontinuous Ferromagnetic Layer Insertion"
    Phys. Rev. Lett. 94, 068304-1~4 (2005).

Review papers

1. Yukio Nozaki, Hiroaki Sukegawa, Shinichi Watanabe, Seiji Yunoki, Taisuke Horaguchi, Hayato Nakayama, Kazuto Yamanoi, Zhenchao Wen, Cong He, Jieyuan Song, Tadakatsu Ohkubo, Seiji Mitani, Kazuki Maezawa, Daichi Nishikawa, Shun Fujii, Mamoru Matsuo, Junji Fujimoto, and Sadamichi Maekawa,,
   "Gyro-spintronic material science using vorticity gradient in solids"
Sci. Technol. Adv. Mater. 26, 2428153-1~39 (2025).
Open access


2. Kelvin Elphick, William Frost, Marjan Samiepour, Takahide Kubota, Koki Takanashi, Hiroki Sukegawa, Seiji Mitani, and Atsufumi Hirohata,
   "Heusler alloys for spintronic devices: review on recent development and future perspectives"
Sci. Technol. Adv. Mater. 22, 235-271 (2021).
STAM Altmetrics Award for 2021
Open access


3. M. Coll, J. Fontcuberta, M. Althammer, M. Bibes, H. Boschker, A. Calleja, G. Cheng, M. Cuoco, R. Dittmann, B. Dkhil, I. El Baggari, M. Fanciulli, I. Fina, E. Fortunato, C. Frontera, S. Fujita, V. Garcia, S.T.B. Goennenwein, C.-G. Granqvist, J. Grollier, R. Gross, A. Hagfeldt, G. Herranz, K. Hono, E. Houwman, M. Huijben, A. Kalaboukhov, D.J. Keeble, G. Koster, L.F. Kourkoutis, J. Levy, M. Lira-Cantu, J.L. MacManus-Driscoll, J. Mannhart, R. Martins, S. Menzel, T. Mikolajick, M. Napari, M.D. Nguyen, G. Niklasson, C. Paillard, S. Panigrahi, G. Rijnders, F. Sanchez, P. Sanchis, S. Sanna, D.G. Schlom, U. Schroeder, K.M. Shen, A. Siemon, M. Spreitzer, H. Sukegawa, R. Tamayo, J. van den Brink, N. Pryds, and F.M. Granozio,
   "Towards Oxide Electronics: a Roadmap"
   Appl. Surf. Sci. 482, 1~92 (2019).
   Open access
   


4. Atsufumi Hirohata, Hiraoki Sukegawa, Hideto Yanagihara, Igor Zutic, Takeshi Seki, Shigemi Mizukami, and Raja Swaminathan,
   "Roadmap for Emerging Materials for Spintronic Device Applications"
   IEEE Trans. Magn. 51, 0800511-1~11 (2015).
   Open access
   


5. H. Sukegawa, Z. C. Wen, S. Kasai, K. Inomata, and S. Mitani,
   "Spin transfer torque switching and perpendicular magnetic anisotropy in full Heusler alloy Co₂FeAl-based tunnel junctions"
   SPIN 4, 1440023-1~15 (2014).

（date of update: Feb. 2025）