Updated on 2021/11/05

写真a

 
OSHIMA Daiki
 
Organization
Graduate School of Engineering Electronics 2 Assistant Professor
Graduate School
Graduate School of Engineering
Undergraduate School
School of Engineering Electrical Engineering, Electronics, and Information Engineering
Title
Assistant Professor

Degree 1

  1. 博士(工学) ( 2014.3   名古屋大学 ) 

Research Interests 2

  1. スピンデバイス

  2. 磁気記録

Professional Memberships 2

  1. The Institute of Electrical and Electronics Engineers

  2. 日本磁気学会

Awards 1

  1. 電気学会 基礎・材料・共通部門 平成28年優秀論文発表賞

    2016   電気学会   MnGa膜を用いたイオン照射型ビットパターン媒体の高密度化の検討

    大島大輝

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

 

Papers 28

  1. Enhancement of spin-orbit torques by change in uniaxial in-plane magnetic anisotropy of Py/Pt bilayers on single crystal 128 degrees Y-Cut LiNbO3 substrate Reviewed

    Ito Masayoshi, Yamaguchi Akinobu, Oshima Daiki, Kato Takeshi, Shima Mutsuhiro, Yamada Keisuke

    APPLIED PHYSICS LETTERS   Vol. 119 ( 15 )   2021.10

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    Language:Japanese  

    DOI: 10.1063/5.0063207

    Web of Science

  2. Topotactic crystal structure transformation from spinet ferrite to wustite in epitaxial Fe3O4 films via Kr ion irradiation Reviewed

    Liu Yang, Hisamatsu Yuki, Sharmin Sonia, Oshima Daiki, Iwata Satoshi, Kato Takeshi, Sekiba Daiichiro, Kita Eiji, Yanagihara Hideto

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A   Vol. 39 ( 3 )   2021.5

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    Language:Japanese  

    DOI: 10.1116/6.0000885

    Web of Science

  3. Progress on efficient current-induced magnetization switching

    Kato Takeshi, Iwata Satoshi, Oshima Daiki

    ELECTRICAL ENGINEERING IN JAPAN   Vol. 212 ( 1-4 ) page: 3 - 10   2020.9

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    Language:Japanese  

    DOI: 10.1002/eej.23278

    Web of Science

  4. Spin orbit torques in ferrimagnetic GdFeCo with various compositions Reviewed

    Kawakami Keisuke, Kato Takeshi, Oshima Daiki, Iwata Satoshi

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 59   2020.4

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    Language:Japanese  

    DOI: 10.7567/1347-4065/ab51b5

    Web of Science

  5. Highly (001) oriented MnAl thin film fabricated on CoGa buffer layer Reviewed

    Oshima Daiki, Kato Takeshi, Iwata Satoshi

    AIP ADVANCES   Vol. 10 ( 2 )   2020.2

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    Authorship:Lead author, Corresponding author   Language:Japanese  

    DOI: 10.1063/1.5130452

    Web of Science

  6. Spin transfer torque switching of hybrid memory layers with low Curie temperature CoPd/Pd multilayers Reviewed

    Zhao Wangzhen, Kimura Takumi, Kato Takeshi, Oshima Daiki, Sonobe Yoshiaki, Takahashi Shigeki, Iwata Satoshi

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   Vol. 493   2020.1

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  7. Patterned arrays of assembled nanoparticles prepared by interfacial assembly and femtosecond laser fabrication

    Jiang Chengpeng, Oshima Daiki, Iwata Satoshi, Pong Philip W. T., Kato Takeshi

    JOURNAL OF NANOPARTICLE RESEARCH   Vol. 22 ( 1 )   2019.12

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    Language:Japanese  

    DOI: 10.1007/s11051-019-4718-8

    Web of Science

  8. MnGa (001)-Textured Film Fabricated on Thermally Oxidized Si Substrate for Application to Ion Beam Bit Patterned Media

    Ishikawa Toru, Miwa Yoshitsugu, Oshima Daiki, Kato Takeshi, Iwata Satoshi

    IEEE TRANSACTIONS ON MAGNETICS   Vol. 55 ( 7 )   2019.7

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    Language:Japanese  

    DOI: 10.1109/TMAG.2018.2889499

    Web of Science

  9. Ion Irradiation for Planar Patterning of Magnetic Materials

    Kato Takeshi, Oshima Daiki, Iwata Satoshi

    CRYSTALS   Vol. 9 ( 1 )   2019.1

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    Language:Japanese  

    DOI: 10.3390/cryst9010027

    Web of Science

  10. Variation of Magnetization Dynamics of Co/Ni Multilayer by Capturing Magnetic Nanoparticles Reviewed

    Otaki Y., Kato T., Okamoto S., Kikuchi N., Oshima D., Iwata S., Kitakami O.

    IEEE TRANSACTIONS ON MAGNETICS   Vol. 54 ( 11 )   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TMAG.2018.2832660

    Web of Science

  11. Hybrid Memory Layer With Low Curie Temperature CoPd/Pd Multilayer for High-Density Magnetic Random-Access Memory Cells Reviewed

    Zhao W., Dong X., Kimura T., Kato T., Oshima D., Sonobe Y., Kawato Y., Iwata S.

    IEEE TRANSACTIONS ON MAGNETICS   Vol. 54 ( 11 )   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TMAG.2018.2828138

    Web of Science

  12. Spin transfer torque switching of Co/Pd multilayers and Gilbert damping of Co-based multilayers

    Kimura Takumi, Dong Xiayin, Adachi Kanta, Oshima Daiki, Kato Takeshi, Sonobe Yoshiaki, Okamoto Satoshi, Kikuchi Nobuaki, Kawato Yoshiaki, Kitakami Osamu, Iwata Satoshi

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 57 ( 9 )   2018.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.7567/JJAP.57.09TD01

    Web of Science

  13. Femtosecond resonant magneto-optical Kerr effect measurement on an ultrathin magnetic film in a soft X-ray free electron laser Reviewed

    Yamamoto Shingo, Kubota Yuya, Yamamoto Kohei, Takahashi Yoshinobu, Maruyama Kohei, Suzuki Yuta, Hobara Rei, Fujisawa Masami, Oshima Daiki, Owada Shigeki, Togashi Tadashi, Tono Kensuke, Yabashi Makina, Hirata Yasuyuki, Yamamoto Susumu, Kotsugi Masato, Wadati Hiroki, Kato Takeshi, Iwata Satoshi, Shin Shik, Matsuda Iwao

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 57 ( 9 )   2018.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.7567/JJAP.57.09TD02

    Web of Science

  14. Spin-valve giant magneto-resistance film with magnetostrictive FeSiB amorphous layer and its application to strain sensors Reviewed

    Hashimoto Y., Yamamoto N., Kato T., Oshima D., Iwata S.

    JOURNAL OF APPLIED PHYSICS   Vol. 123 ( 11 )   2018.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.5018467

    Web of Science

  15. Switching Field Distribution of MnGa Bit Patterned Film Fabricated by Ion Beam Irradiation Reviewed

    Oshima D., Kato T., Iwata S.

    IEEE TRANSACTIONS ON MAGNETICS   Vol. 54 ( 2 )   2018.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TMAG.2017.2733765

    Web of Science

  16. Hybrid memory layer with low Curie temperature CoPd/Pd multilayer for high-density magnetic random access memory cells

    Zhao W., Kimura T., Kato T., Oshima D., Sonobe Y., Kawato Y., Iwata S.

    2018 IEEE INTERNATIONAL MAGNETIC CONFERENCE (INTERMAG)     2018

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    Language:Japanese  

    Web of Science

  17. Nano spin-diodes using FePt-NDs with huge on/off current ratio at room temperature Reviewed

    K. Makihara, T. Kato, Y. Kabeya, Y. Mitsuyuki, A. Ohta, D. Oshima, S. Iwata, Y. Darma, M. Ikeda, S. Miyazaki

    Scientific Reports   Vol. 6   page: 33409   2016.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/srep33409

  18. Ferromagnetic Resonance of a Single Magnetochiral Metamolecule of Permalloy Reviewed

    T. Kodama, S. Tomita, T. Kato, D. Oshima, S. Iwata, S. Okamoto, N. Kikuchi, O. Kitakami, N. Hosoito, H. Yanagi

    Physical Review Applied   Vol. 6   page: 024016-1-9   2016.8

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    Language:English   Publishing type:Research paper (scientific journal)  

  19. Effective Damping Constant and Current Induced Magnetization Switching of GdFeCo/TbFe Exchange-Coupled Bilayers Reviewed

    T. Higashide, B. Dai, T. Kato, D. Oshima, S. Iwata

      Vol. 7   page: 3505605   2016.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/LMAG.2016.2595502

  20. Nanoscale patterning of CrPt3 magnetic thin films by using ion beam irradiation Reviewed

    E. Suharyadi, D. Oshima, T. Kato, S. Iwata

    Results in Physics   Vol. 6   page: 186-188   2016.4

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.rinp.2016.03.010

  21. Ion irradiation induced magnetic transition of MnGa alloy films studied by X-ray magnetic circular dichroism and low-temperature hysteresis loops Reviewed

    D. Oshima, M. Tanimoto, T. Kato, Y. Fujiwara, T. Nakamura, Y. Kotani, S. Tsunashima, S. Iwata

    IEEE Transactions on Magnetics   Vol. 52 ( 7 ) page: 3201804-1-4   2016.2

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TMAG.2016.2527050

  22. Structure and Magnetic Properties of (001) Oriented CoPt-Ag and CoPd-Ag Alloy Films Reviewed

    T. Nagata, Y. Tokuoka, T. Kato, D. Oshima, S. Iwata

    Journal of Magnetics Society of Japan   Vol. 40 ( 1 ) page: 13-17   2016.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3379/msjmag.1512R003

  23. Anomalous structural behavior in the metamagnetic transition of FeRh thin films from a local viewpoint Reviewed

    Y. Wakisaka, Y. Uemura, T. Yokoyama, H. Asakura, H. Morimoto, M. Tabuchi, D. Oshima, T. Kato, S. Iwata

    Physical Review B   Vol. 92   page: 184408   2015.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevB.92.184408

  24. Magnetization control for bit pattern formation of spinel ferromagnetic oxides by Kr ion implantation Reviewed

    E. Kita, K. Z. Suzuki, Y. Liu, Y. Utsumi, J. Morishita, D. Oshima, T. Kato, T. Niizeki, K. Mibu, H. Yanagihara

    Journal of Applied Physics   Vol. 115   page: 17B907   2014

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  25. Control of magnetic properties of MnGa films by Kr+ ion irradiation for application to bit patterned media Reviewed

    D. Oshima, T. Kato, S. Iwata, S. Tsunashima

    IEEE Transactions on Mgnetics   Vol. 49 ( 7 ) page: 3608-3611   2013

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  26. Observation of ferri-nonmagnetic boundary in CrPt3 line-and-space patterned media using a dark-field transmission electron microscope Reviewed

    D. Oshima, E. Suharyadi, T. Kato, S. Iwata

    Journal of Magnetism and Magnetic Materials   Vol. 324   page: 1617-1621   2012

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  27. Switching field distribution of planar-patterned CrPt3 nanodots fabricated by ion irradiation Reviewed

    E. Suharyadi, D. Oshima, T. Kato, S. Iwata

    Journal of Applied Physics   Vol. 109   page: 07B771   2011

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  28. Fabrication of L12-CrPt3 Alloy Using Rapid Thermal Annealing for Planar Bit Patterned Media Reviewed

    T. Kato, D. Oshima, Y. Yamauchi, S. Iwata, S. Tsunashima

    IEEE Transactions on Magnetics   Vol. 46 ( 6 ) page: 1671-1674   2010

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    Language:English   Publishing type:Research paper (scientific journal)  

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Presentations 16

  1. ビットパターン媒体に用いるSi基板上MnGa (001)配向膜の作製

    三輪佳嗣,石川徹,大島大輝,加藤剛志,岩田聡

    第42回日本磁気学会学術講演会 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  2. 低キュリー温度CoPd/Pd系多層膜を用いたMRAM用交換結合ハイブリッドメモリ層

    趙望臻,木村匠,董夏茵,大島大輝,加藤剛志,園部義明,川戸良昭,岩田聡

    第42回日本磁気学会学術講演会 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  3. Co/Pd多層膜のスピン注入磁化反転臨界電流の層厚比依存性

    趙望臻,木村匠,大島大輝,加藤剛志,園部義明,川戸良昭,岩田聡

    第42回日本磁気学会学術講演会 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  4. CoGa下地層を用いた極薄L10-MnGa膜の磁気パターニング

    堀江祐貴,三輪佳嗣,大島大輝,加藤剛志,岩田聡

    第42回日本磁気学会学術講演会 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  5. Fe3O4 / Cr 多層膜における垂直磁気異方性

    大島大輝,加藤剛志,岩田聡

    第42回日本磁気学会学術講演会 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  6. Ion beam patterning of ultrathin L10-MnGa (001) film grown on CoGa buffer layer International conference

    Y. Horie, D. Oshima, T. Kato, S. Iwata

    IEEE International Magnetics Conference 2018 

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    Event date: 2018.4

    Language:English   Presentation type:Poster presentation  

    Country:Singapore  

  7. Scanning X-ray magnetic circular dichroism observation of magnetic state of ion-irradiation bit patterned L10-MnGa films International conference

    T. Ishikawa, K. Fukuta, D. Oshima, T. Kato, T. Nakamura, Y. Kotani, K. Toyoki, S. Iwata

    International Conference on Materials and Systems for Sustainability 

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    Event date: 2017.9 - 2017.10

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  8. 走査型XMCD顕微鏡によるイオン照射型L10-MnGaビットパターン膜の局所的磁気状態の評価

    石川徹,福田憲吾,大島大輝,加藤剛志,中村哲也,小谷佳範,豊木研太郎,岩田聡

    第41回日本磁気学会学術講演会 

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    Event date: 2017.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  9. イオン照射により作製したMnGaビットパターン膜のFORC解析

    大島大輝,加藤剛志,岩田聡

    第41回日本磁気学会学術講演会 

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    Event date: 2017.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  10. Ion Beam Bit Patterned Media Using MnGa Alloy Films Invited International conference

    D. Oshima, T. Kato, S. Iwata

    The 28th Magnetic Recording Conference 

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    Event date: 2017.8

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Tsukuba, Japan   Country:Japan  

  11. First order reversal curve diagram analysis of ion irradiated bit patterned MnGa film International conference

    D. Oshima, T. Kato, S. Iwata

    IEEE International Magnetics Conference 2017 

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    Event date: 2017.4

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Dublin, Ireland   Country:Japan  

  12. Ion irradiation induced magnetic transition of MnGa alloy films studied by X-ray magnetic circular dichroism and low-temperature hysteresis loops International conference

    D. Oshima, M. Tanimoto, T. Kato, Y. Fujiwara, T. Nakamura, Y. Kotani, S. Tsunashima, S. Iwata

    2016 Joint MMM-Intermag Conference 

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    Event date: 2016.1

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  13. Control of Magnetic Inactivation Layer Thickness in MnGa Film by Kr Ion Irradiation International conference

    D. Oshima, T. Kato, S. Takahashi, Y. Sonobe, S. Iwata, S. Tsunashima

    20th International Conference on Magnetism 

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    Event date: 2015.7

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  14. (001) Oriented MnGa Film Grown on Si Substrate for Ion Beam Patterned Media International conference

    D. Oshima, T. Negoro, T. Kato, S. Iwata, S. Tsunashima

    20th International Conference on Magnetism 

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    Event date: 2015.7

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  15. Anisotropic X-ray magnetic circular dichroism spectra of (001) oriented L10-MnGa film International conference

    D. Oshima, M. Tanimoto, T. Kato, Y. Fujiwara, T. Nakamura, Y. Kotani, S. Tsunashima, S. Iwata

    IEEE International Magnetics Conference 2015 

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    Event date: 2015.5

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  16. Magnetic circular dichroism measurement of ion irradiated MnGa films International conference

    D. Oshima, M. Tanimoto, T. Kato, Y. Fujiwara, T. Nakamura, Y. Kotani, S. Tsunashima, S. Iwata

    IEEE International Magnetics Conference 2014 

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    Event date: 2014.5

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

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KAKENHI (Grants-in-Aid for Scientific Research) 7

  1. 高密度スキルミオン流の流体力学的輸送特性の研究

    Grant number:21H01029  2021.4 - 2024.3

    科学研究費助成事業  基盤研究(B)

    長尾 全寛, 大島 大輝

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    Authorship:Coinvestigator(s) 

    磁気スキルミオンは安定な粒子として振る舞い、超低密度電流駆動を示すことからスキルミオンを情報キャリアとして利用する応用的価値に注目が集まっている。特に、スキルミオン間相互作用が存在する高密度スキルミオンの集団的運動は、非圧縮性トポロジカル粒子流という分野横断的な舞台を提供する可能性があり、デバイス応用を目指す上でもその解明は重要である。本研究では、高密度スキルミオンの集団的運動の特性を流体力学的アプローチによって解明する。特に、高密度スキルミオンの集団的運動はスキルミオン間相互作用に起因するスキルミオン粘性流の発現が見込まれ、超高速駆動やホール粘性などの新規輸送特性の観測が期待される。

  2. 空間対称性の破れの制御によるスピン軌道トルクの増強と3次元メモリへの展開

    Grant number:20H02182  2020.4 - 2023.3

    科学研究費助成事業  基盤研究(B)

    加藤 剛志, 大島 大輝

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    Authorship:Coinvestigator(s) 

    スピン軌道トルク(SOT)磁化反転は磁性層に隣接する非磁性層に電流を流すことで磁化反転を行なうもので,既存のスピン移行トルク(STT)磁化反転に比べ1/5程度の消費電力で10倍高速に磁化反転ができると考えら,今後のSociety 5.0を支える大容量磁気ランダムアクセスメモリ(MRAM)への応用研究が進められている.本研究は磁性材料に空間反転対称性の破れを人工的に導入することで,SOT磁化反転の高効率化を図るとともに,これを利用した3次元メモリの原理実証を行なう.

  3. 強磁性酸化物を用いた人工積層膜の電圧駆動メモリデバイスへの応用

    Grant number:19K15044  2019.4 - 2021.3

    科学研究費助成事業  若手研究

    大島 大輝

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    Authorship:Principal investigator 

    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    現在のスピントロニクスデバイスにおいては,電流誘起の磁化反転手法が主流であるが,省電力化のためには電圧誘起の磁化反転手法が望ましい.本研究課題では,電圧誘起磁化反転手法に適する材料として,【強磁性絶縁体 / 強磁性金属 / 非磁性金属】の繰り返し構造を有する人工積層膜を提案し,その基礎的特性・動作に関する研究を行う.
    本年度は、強磁性絶縁体/強磁性金属/非磁性金属を繰り返した人工積層膜の作製を試み、垂直磁気異方性を生じる作製条件の検討を行った。強磁性絶縁体としてNiフェライト、強磁性金属としてFeCo、非磁性金属としてCrを選択し、マグネトロンスパッタリング法を用いてサンプルの成膜を行った。Niフェライト、FeCo、Crの膜厚はそれぞれ、3、0.6、10 nmとした。成膜後、真空中で熱処理を行いサンプルの磁気特性を測定した。熱処理温度により垂直磁気異方性の大きさは変化し、200もしくは250度のときに垂直磁気異方性が大きくなるという結果が得られた。これは、熱処理により強磁性絶縁体と強磁性金属の界面状態が変化したためと考えられる。ただし、得られた垂直磁気異方性エネルギーは反磁界エネルギーより僅かに小さく、結果としてサンプル全体では面内磁化膜となってしまっている。この一因はNiフェライトにあると推測される。過去の報告によると、Niフェライトは磁歪により負の垂直磁気異方性を持つとされており、それが膜全体の垂直磁気異方性を低くしてしまった可能性がある。そのため、磁化が比較的小さく、絶縁性の高いZnフェライトを用いて実験を行うことを予定している。また、非磁性金属としてCrを選択したが、スピントルク磁化反転を行うには、スピン軌道相互作用の大きなPt等が望ましい。次年度はZnフェライトやPtを用いた膜構成の検討も行う。
    以上のように、サンプルは面内磁化膜になってしまったものの、比較的垂直磁気異方性の大きなサンプルが作製できたため、電圧印加を試すことができるサンプルの作製に成功したと言える。
    所望の磁気特性には少し届かなかったものの、初年度で計画していた電圧印加を試すサンプルの作製には成功し、次年度に予定していた実験は開始可能である。
    次年度では予定していた、電圧印加により磁気特性を制御する実験を行う。微細加工技術により数μm幅のホールクロスを作製し、その上に絶縁層を介して電圧印加用の電極を形成する。電極に電圧を印加した際の磁気特性の変化をホール測定もしくはKerr効果測定により測定するが、電極はそれぞれの測定に合わせてAl、もしくは透明電極であるITOとする予定である。この実験を積層膜の繰り返し回数を変化させて行うことで、繰り返し数が多くなっても、電圧印加による磁気特性の変調が有効かを調べる。
    次に、電圧アシスト磁化反転の実験を試みる予定であるが、そのためには膜構成の検討が必要であると考えている。Crによりスピンホール効果が生じるかは不明だが一般的にはその効果は大きくないと考えられるため、Crをスピン軌道相互作用の大きなPtにすることが望ましい。併せて、NiフェライトからZnフェライトへの変更も検討する。負の垂直磁気異方性を有すると報告されているNiフェライトは膜全体の垂直磁気異方性を低減させる原因になる可能性があるため、Znフェライトに変更し、垂直磁気異方性の向上を狙う。電圧アシスト磁化反転実験を行う素子の検討も行う。膜をホールクロスに加工しただけでは形状異方性の影響によりサンプルは面内磁化膜になりやすいが、サンプルを数百から数十nmのドット状に加工すれば、形状磁気異方性の効果が小さくなり、サンプルは垂直磁化を保ちやすいと考えられる。膜構成の検討、素子構造の検討を行うことにより、無磁場で磁化が基板法線方向を向くサンプルの作製を試みる。その後、電圧アシスト磁化反転を試みる。

  4. Magnetization switching by spin current induced by ultra short pulse laser

    Grant number:17K18878  2017.6 - 2019.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Research (Exploratory)

    Kato Takeshi

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    Authorship:Coinvestigator(s) 

    In order to observe spin current generation by the ultra short pulse laser and the magnetization switching by the spin current, two experiments, 1) spin current injection to Au from 3d transition metal Fe and 2) magnetization switching of GdFeCo by injecting the spin current, were carried out. Fe thickness dependence of the damping constant of Fe showed the Au layer has useful properties as a spin current conductor. When the spin current injected to GdFeCo, the moment of GdFeCo feels large equivalent magnetic field around the compensation composition. Moreover, it was found that the injected spin current exerts a torque to only FeCo moment.

  5. Local magnetization control using spin Hall effect and its application to GMR magnetic sensors

    Grant number:17H03249  2017.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Iwata Satoshi

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    Authorship:Coinvestigator(s) 

    In this research project, we have developed strain-sensor using giant magnetoresistance effect, where inverse magneto-striction effect is applied to the magnetic free layer in a spin valve structure. In order to avoid from influence of magnetic stray field, we employ sinusoidal signal detection method, where the magnetization direction of the magnetic free layer was modulated by alternative magnetic field by flowing AC current through Al strip line formed on GMR element. In next stage, we have investigated magnetization control by spin-Hall effect. The sensor device is composed from Ta/FeCo layer for producing spin current, a magnetoresistive spin-valve element and anti-ferromagneic NiO layer which magnetically connects Ta/FeCo and spin-valve layers. In this device, magnetization reversal by spin Hall effect was observed.

  6. Control of spin dynamics by electric field and electric-field-assisted spin Hall switching

    Grant number:16H04328  2016.4 - 2019.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Kato Takeshi

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    Authorship:Coinvestigator(s) 

    Spin Hall switching is considered as a promising way of the next generation writing scheme of the magnetic random access memories. This study focused on the effect of the applied electric field on the spin Hall switching of Co and Fe ultrathin films, where the electric field was applied thorough HfO2/MgO insulation layer. Moreover, the effect of the electric field on the spin dynamics was also studied. The coercivity and current density of the spin Hall switching were modified by the electric field as 43 %/(V/m) and 20 %/(V/m), respectively. The modifications of the coercivity and the current density of the spin Hall switching by the electric field were found to be sensitive to the deposition condition of the insulation layer.

  7. Control of magnonic crystal by voltage

    Grant number:16K18091  2016.4 - 2018.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    OSHIMA Daiki

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    Authorship:Principal investigator 

    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    Development of materials was carried out in order to control spin wave by using periodic nano-sized electrodes. First, voltage was applied to the fabricated samples, however, the voltage effect was not obtained. Thinning the sample was tried because it was effective to obtain a voltage effect. As a result, thinning the sample without degrading the property of the sample was successful. In addition, a multilayered structure of ferromagnetic insulator / ferromagnetic metal / nonmagnetic metal was suggested as a new system for voltage application, and the prototype of the structure was fabricated. It was found that the fabricated structure had a perpendicular magnetic anisotropy. In the future, micro-fabrication process will be optimized and the experiment for voltage application will be carried out.

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Teaching Experience (On-campus) 4

  1. 電気磁気学基礎演習

    2015

  2. 電気電子工学実験

    2015

  3. 電気磁気学基礎演習

    2014

  4. 電気電子工学実験

    2014