Details of the Researcher

PHOTO

Nobuki Tezuka
Section
Graduate School of Engineering
Job title
Professor
Degree

  • 博士（工学）（東北大学）

  • 修士（工学）（東北大学）

Committee Memberships 6

  • 日本磁気学会　現地実行委員

    2007/10 - 2008/09

  • 日本磁気学会　現地実行委員

    2007/10 - 2008/09

  • 19th International Colloquium on Magnetic Films and Surfaces現地実行委員　現地実行委員

    2006/08 -

  • 19th International Colloquium on Magnetic Films and Surfaces現地実行委員　現地実行委員

    2006/08 -

  • 第65 回応用物理学会学術講演会現地実行委員　現地実行委員

    2004/09 -

  • 第65 回応用物理学会学術講演会現地実行委員　現地実行委員

    2004/09 -

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Professional Memberships 4

  • 日本応用物理学会

  • 日本金属学会

  • 日本物理学会

  • 日本応用磁気学会

Research Areas 3

  • Nanotechnology/Materials / Crystal engineering /

  • Nanotechnology/Materials / Applied materials /

  • Nanotechnology/Materials / Structural and functional materials /

Papers 171

  1. Increase of energy products of Zn-bonded Sm-Fe-N magnets with low oxygen content. Peer-reviewed

    Masashi Matsuura, Yuki Nishijima, Nobuki Tezuka, Satoshi Sugimoto, Tetsuya Shoji, Noritsugu Sakuma

    Journal of Magnetism and Magnetic Materials　467　64-68　2018/12

    Publisher: Elsevier BV

    DOI： 10.1016/j.jmmm.2018.07.064 　

    ISSN： 0304-8853

  2. Voltage control of a magnetic switching field for magnetic tunnel junctions with low resistance and perpendicular magnetic anisotropy Peer-reviewed

    N. Tezuka, S. Oikawa, M. Matsuura, S. Sugimoto, K. Nishimura, T. Irisawa, Y. Nagamine, K. Tsunekawa

    AIP Advances　8　(5)　55922-1-55922-5　2018/05/01

    Publisher: American Institute of Physics Inc.

    DOI： 10.1063/1.5006398 　

    ISSN： 2158-3226

    eISSN： 2158-3226

  3. High coercive Zn-bonded Sm-Fe-N magnets prepared using fine Zn particles with low oxygen content Peer-reviewed

    Masashi Matsuura, Tomoki Shiraiwa, Nobuki Tezuka, Satoshi Sugimoto, Tetsuya Shoji, Noritsugu Sakuma, Kazuaki Haga

    Journal of Magnetism and Magnetic Materials　452　243-248　2018/04/15

    Publisher: Elsevier B.V.

    DOI： 10.1016/j.jmmm.2017.12.059 　

    ISSN： 0304-8853

  4. Interfacial crystal structures and non-local spin signals of Co2FeAl0.5Si0.5/n-GaAs junctions Peer-reviewed

    Kohei Kataoka, Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    IEEE Transactions on Magnetics　54　(1)　4400103-1-4400103-3　2018/01/01

    Publisher: Institute of Electrical and Electronics Engineers Inc.

    DOI： 10.1109/TMAG.2017.2756986 　

    ISSN： 0018-9464

  5. Effect of hydrogenation disproportionation conditions on magnetic anisotropy in Nd-Fe-B powder prepared by dynamic hydrogenation disproportionation desorption recombination Peer-reviewed

    Masao Yamazaki, Takashi Horikawa, Chisato Mishima, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    AIP ADVANCES　7　(5)　056220　2017/05

    DOI： 10.1063/1.4975697 　

    ISSN： 2158-3226

  6. Effect of hydrogenation disproportionation conditions on magnetic anisotropy in Nd-Fe-B powder prepared by dynamic hydrogenation disproportionation desorption recombination. Peer-reviewed

    TEZUKA Nobuki

    AIP Advances　7　(5)　056220-1-056220-8　2017/02

  7. Study of an Al-Ca Alloy with Low Young's Modulus Peer-reviewed

    Jun Yu, Yasuo Ishiwata, Yoshihiro Taguchi, Daisuke Shimosaka, Ryosuke Taniguchi, Takutoshi Kondo, Nobuki Tezuka

    LIGHT METALS 2017　167-171　2017

    DOI： 10.1007/978-3-319-51541-0_23 　

    ISSN： 2367-1181

  8. Improvement of Coercivity of Nd-Fe-B Powder by Nd-Cu Sputtering Peer-reviewed

    Ami Iijima, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa

    MATERIALS TRANSACTIONS　58　(5)　825-828　2017

    DOI： 10.2320/matertrans.M2016448 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  9. Effect of post annealing on spin accumulation and transport signals in Co2FeSi/MgO/n(+)-Si on insulator devices Peer-reviewed

    Ajay Tiwari, Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Nobuki Tezuka, Yoshiaki Saito

    AIP ADVANCES　6　(7)　075119　2016/07

    DOI： 10.1063/1.4960210 　

    ISSN： 2158-3226

  10. High-Coercivity Fe-Co Nanoparticles Prepared by Pulsed Arc Plasma Deposition Peer-reviewed

    Daiki Horiyama, Masashi Matsuura, Tetsuro Yamamoto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　57　(2)　207-211　2016/02

    DOI： 10.2320/matertrans.MAW201510 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  11. Spin Injection, Transport, and Detection in a Lateral Spin Transport Devices with Co2FeAl0.5Si0.5/n-GaAs, Co2FeSi/MgO/n-Si, and CoFe/MgO/n-Si Junctions Peer-reviewed

    Nobuki Tezuka, Yoshiaki Saito

    MATERIALS TRANSACTIONS　57　(6)　767-772　2016

    DOI： 10.2320/matertrans.ME201502 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  12. Perpendicular Magnetic Tunnel Junctions With Low Resistance-Area Product: High Output Voltage and Bias Dependence of Magnetoresistance Peer-reviewed

    N. Tezuka, S. Oikawa, I. Abe, M. Matsuura, S. Sugimoto, K. Nishimura, T. Seino

    IEEE MAGNETICS LETTERS　7　3104104-3104204　2016

    DOI： 10.1109/LMAG.2016.2584582 　

    ISSN： 1949-307X

  13. Influence of Swaging on the Magnetic Properties of Zn-Bonded Sm-Fe-N Magnets Peer-reviewed

    Kohei Kataoka, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　56　(10)　88-92　2015/10

    DOI： 10.2320/matertrans.M2015190 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  14. Increased uniaxial perpendicular anisotropy in tetragonally distorted FeCo-Ti-N films Peer-reviewed

    Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    JOURNAL OF APPLIED PHYSICS　117　(17)　17A738　2015/05

    DOI： 10.1063/1.4916763 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  15. Correlation between amplitude of spin accumulation signals investigated by Hanle effect measurement and effective junction barrier height in CoFe/MgO/n(+)-Si junctions Peer-reviewed

    Y. Saito, M. Ishikawa, H. Sugiyama, T. Inokuchi, K. Hamaya, N. Tezuka

    JOURNAL OF APPLIED PHYSICS　117　(17)　17C707　2015/05

    DOI： 10.1063/1.4907242 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  16. Effects of Hydrogenation-Disproportionation-Desorption-Recombination Processing Parameters on the Particle Size of Ultrafine Jet-Milled Nd-Fe-B Powders Peer-reviewed

    Michihide Nakamura, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa

    MATERIALS TRANSACTIONS　56　(1)　129-134　2015/01

    DOI： 10.2320/matertrans.M2014273 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  17. Comparison of Spin Signals Between 3T Hanle and 4T Non-Local Methods for Co2Fe(Al,Si)/n-GaAs Junctions Peer-reviewed

    Nobuki Tezuka, Tatsuya Saito, Masashi Matsuura, Satoshi Sugimoto

    IEEE TRANSACTIONS ON MAGNETICS　50　(11)　2600204　2014/11

    DOI： 10.1109/TMAG.2014.2325942 　

    ISSN： 0018-9464

    eISSN： 1941-0069

  18. Effect of Annealing on Magnetic Properties of Ultrafine Jet-Milled Nd-Fe-B Powders Peer-reviewed

    Michihide Nakamura, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa

    MATERIALS TRANSACTIONS　55　(10)　1582-1586　2014/10

    DOI： 10.2320/matertrans.MAW201402 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  19. Microstructure and coercivity of nitrided Mn-Sn-based alloys Peer-reviewed

    Masashi Matsuura, Keita Isogai, Keita Shinaji, Nobuki Tezuka, Satoshi Sugimoto

    JOURNAL OF ALLOYS AND COMPOUNDS　605　208-212　2014/08

    DOI： 10.1016/j.jallcom.2014.03.158 　

    ISSN： 0925-8388

    eISSN： 1873-4669

  20. Large spin-accumulation signal in Si for epitaxial CoFe/highly (100)-textured MgO/Si devices Peer-reviewed

    H. Sugiyama, M. Ishikawa, T. Inokuchi, T. Tanamoto, Y. Saito, N. Tezuka

    SOLID STATE COMMUNICATIONS　190　49-52　2014/07

    DOI： 10.1016/j.ssc.2014.03.019 　

    ISSN： 0038-1098

    eISSN： 1879-2766

  21. Local magnetoresistance through Si and its bias voltage dependence in ferromagnet/MgO/silicon-on-insulator lateral spin valves Peer-reviewed

    Y. Saito, T. Tanamoto, M. Ishikawa, H. Sugiyama, T. Inokuchi, K. Hamaya, N. Tezuka

    JOURNAL OF APPLIED PHYSICS　115　(17)　17C514　2014/05

    DOI： 10.1063/1.4866699 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  22. Maximum magnitude in bias-dependent spin accumulation signals of CoFe/MgO/Si on insulator devices Peer-reviewed

    M. Ishikawa, H. Sugiyama, T. Inokuchi, T. Tanamoto, K. Hamaya, N. Tezuka, Y. Saito

    JOURNAL OF APPLIED PHYSICS　114　(24)　243904　2013/12

    DOI： 10.1063/1.4856955 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  23. Influence of Heat Treatment on the Microstructure and Magnetic Properties of Mn-Sn-Co-N Alloys Peer-reviewed

    Keita Shinaji, Tsuyoshi Mase, Keita Isogai, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　54　(10)　2007-2010　2013/10

    DOI： 10.2320/matertrans.MAW201312 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  24. Spin injection, transport, and detection at room temperature in a lateral spin transport device with Co2FeAl0.5Si 0.5/n-GaAs schottky tunnel junctions Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    Applied Physics Express　6　(10)　103006　2013/10

    DOI： 10.7567/APEX.6.103006 　

    ISSN： 1882-0778 1882-0786

  25. Four-terminal nonlocal signals in lateral spin transport devices with variously ordered Co2FeAl0.5Si0.5 full-Heusler alloy electrodes Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    Applied Physics Letters　103　(12)　122401　2013/09/16

    DOI： 10.1063/1.4821451 　

    ISSN： 0003-6951

  26. Crystal Structures and Spin Injection Signals of Si/Mg/MgO/Co2FeAl0.5Si0.5 Junctions Peer-reviewed

    Takashi Onodera, Masahiro Yoshida, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto, Yoshiaki Saito

    MATERIALS TRANSACTIONS　54　(8)　1392-1395　2013/08

    DOI： 10.2320/matertrans.M2013139 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  27. Preparation of ultrafine jet-milled powders for Nd-Fe-B sintered magnets using hydrogenation-disproportionation-desorption-recombination and hydrogen decrepitation processes Peer-reviewed

    Michihide Nakamura, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa

    APPLIED PHYSICS LETTERS　103　(2)　22404　2013/07

    DOI： 10.1063/1.4813399 　

    ISSN： 0003-6951

  28. Non-Local and Local Spin Signals in a Lateral Spin Transport Device With Co2FeAl0.5Si0.5/n-GaAs Schottky Tunnel Junctions Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    IEEE TRANSACTIONS ON MAGNETICS　49　(7)　4327-4330　2013/07

    DOI： 10.1109/TMAG.2013.2248053 　

    ISSN： 0018-9464

    eISSN： 1941-0069

  29. Microwave absorption properties of polymer composites with amorphous Fe-B and Ni-Zn-Co ferrite nanoparticles Peer-reviewed

    Kazuaki Shimba, Shozo Yuki, Nobuki Tezuka, Satoshi Sugimoto

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY　62　(12)　2123-2127　2013/07

    DOI： 10.3938/jkps.62.2123 　

    ISSN： 0374-4884

  30. Preparation of ultrafine jet-milled powders for Nd-Fe-B sintered magnets using hydrogenation-disproportionation-desorption-recombination and hydrogen decrepitation processes Peer-reviewed

    Michihide Nakamura, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa

    APPLIED PHYSICS LETTERS　103　(2)　022404　2013/07

    DOI： 10.1063/1.4813399 　

    ISSN： 0003-6951

  31. Three-Terminal Hanle Signals in Schottky Tunnel Junctions with Co2FeAl0.5Si0.5 Full-Heusler Alloy Electrodes Deposited at Various Temperatures Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    JAPANESE JOURNAL OF APPLIED PHYSICS　52　(6)　UNSP 063001　2013/06

    DOI： 10.7567/JJAP.52.063001 　

    ISSN： 0021-4922

    eISSN： 1347-4065

  32. Three-Terminal Hanle Signals in Schottky Tunnel Junctions with Co2FeAl0.5Si0.5 Full-Heusler Alloy Electrodes Deposited at Various Temperatures Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Masashi Matsuura, Satoshi Sugimoto

    JAPANESE JOURNAL OF APPLIED PHYSICS　52　(6)　2013/06

    DOI： 10.7567/JJAP.52.063001 　

    ISSN： 0021-4922

    eISSN： 1347-4065

  33. Crystal structure and spin conduction property of Co2FeAl 0.5Si0.5 full-heusler alloy thin films deposited on Si substrates Peer-reviewed

    Masahiro Yoshida, Takashi Onodera, Nobuki Tezuka, Satoshi Sugimoto, Yoshiaki Saito

    Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals　77　(3)　85-88　2013/03

    DOI： 10.2320/jinstmet.77.85 　

    ISSN： 0021-4876

  34. Non-local and Local Spin Signals in a Lateral Spin Transport Device with Schottky Tunnel Junctions Peer-reviewed

    T. Saito, N. Tezuka, M. Matsuura, S. Sugimoto

    IEEE Trans.Magn.　40　(7)　0-0　2013

    DOI： 10.1109/TMAG.2013.2248053 　

  35. Si基板上への(001)配向MgO薄膜の作製 Peer-reviewed

    小野寺学史, 吉田昌弘, 手束展規, 杉本諭, 斉藤好昭

    日本金属学会誌　77　(3)　89-93　2013

    DOI： 10.2320/jinstmet.77.89 　

  36. Si上に作製したCo2FeAl0.5Si0.5フルホイスラー合金薄膜の結晶構造とスピン伝導特性 Peer-reviewed

    吉田昌弘, 小野寺学史, 手束展規, 杉本諭, 斉藤好昭

    日本金属学会誌　77　(3)　85-88　2013

    DOI： 10.2320/jinstmet.77.85 　

  37. Fabrication of (001)-Oriented MgO Thin Films on Si Substrates Peer-reviewed

    Onodera, Takashi Yoshida, Masahiro Tezuka, Nobuki Sugimoto, Satoshi Saito, Yoshiaki

    J. Jpn. Inst. Met.　77　(3)　89-93　2013

    DOI： 10.2320/jinstmet.77.89 　

  38. Magnetic properties of mnbi fine particles fabricated using hydrogen plasma metal reaction Peer-reviewed

    Keita Isogai, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    Materials Transactions　54　(9)　1673-1677　2013

    DOI： 10.2320/matertrans.MAW201306 　

    ISSN： 1345-9678

  39. Fabrication of (001)-Oriented MgO Thin Films on Si Substrates Peer-reviewed

    Takashi Onodera, Masahiro Yoshida, Nobuki Tezuka, Satoshi Sugimoto, Yoshiaki Saito

    JOURNAL OF THE JAPAN INSTITUTE OF METALS　77　(3)　89-93　2013

    DOI： 10.2320/jinstmet.77.89 　

    ISSN： 0021-4876

    eISSN： 1880-6880

  40. Microstructure and magnetic properties of Mn-Sn-N and Mn-Sn-Co-N alloys Peer-reviewed

    Keita Isogai, Keita Shinaji, Tsuyoshi Mase, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    Materials Transactions　54　(7)　1236-1239　2013

    DOI： 10.2320/matertrans.M2013113 　

    ISSN： 1345-9678

  41. Spin-Based MOSFETs for Logic and Memory Applications and Spin Accumulation Signals in CoFe/Tunnel Barrier/SOI Devices Peer-reviewed

    Yoshiaki Saito, Mizue Ishikawa, Tomoaki Inokuchi, Hideyuki Sugiyama, Tetsufumi Tanamoto, Kohei Hamaya, Nobuki Tezuka

    IEEE TRANSACTIONS ON MAGNETICS　48　(11)　2739-2745　2012/11

    DOI： 10.1109/TMAG.2012.2202277 　

    ISSN： 0018-9464

    eISSN： 1941-0069

  42. New materials research for high spin polarized current Invited Peer-reviewed

    Nobuki Tezuka

    Journal of Magnetism and Magnetic Materials　324　(21)　3588-3592　2012/10

    DOI： 10.1016/j.jmmm.2012.02.097 　

    ISSN： 0304-8853

  43. New materials research for high spin polarized current Invited Peer-reviewed

    Nobuki Tezuka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　324　(21)　3588-3592　2012/10

    DOI： 10.1016/j.jmmm.2012.02.097 　

    ISSN： 0304-8853

    eISSN： 1873-4766

  44. Microstructure evaluation for Dy-free Nd-Fe-B sintered magnets with high coercivity Peer-reviewed

    R. Goto, M. Matsuura, S. Sugimoto, N. Tezuka, Y. Une, M. Sagawa

    JOURNAL OF APPLIED PHYSICS　111　(7)　07A739　2012/04

    DOI： 10.1063/1.3680190 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  45. Spin injection and detection between CoFe/AlOx junctions and SOI investigated by Hanle effect measurements Peer-reviewed

    Tomoaki Inokuchi, Mizue Ishikawa, Hideyuki Sugiyama, Yoshiaki Saito, Nobuki Tezuka

    JOURNAL OF APPLIED PHYSICS　111　(7)　07C316　2012/04

    DOI： 10.1063/1.3677930 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  46. Temperature and Bias Voltage Dependencies of Spin Injection Signals for CO2FeAl0.5Si0.5/n-GaAs Schottky Tunnel Junction Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　53　(4)　641-644　2012/04

    DOI： 10.2320/matertrans.MBW201113 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  47. Tunnel magnetoresistance effect in magnetic tunnel junctions with epitaxial Co 2FeAl 0.5Si 0.5 Heusler electrodes on MgO (110) single substrates Peer-reviewed

    N. Tezuka, F. Mitsuhashi, S. Sugimoto

    Journal of Applied Physics　111　(7)　07C718　2012/04/01

    DOI： 10.1063/1.3678586 　

    ISSN： 0021-8979

  48. Magnetic and microwave absorption properties of polymer composites with amorphous Fe-B/Ni-Zn ferrite nanoparticles Peer-reviewed

    Kazuaki Shimba, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS　177　(2)　251-256　2012/02

    DOI： 10.1016/j.mseb.2011.12.002 　

    ISSN： 0921-5107

  49. アモルファスFe-B 粒子樹脂複合体の電磁波吸収特性 Peer-reviewed

    結城翔三, 榛葉和晃, 手束展規, 杉本諭

    日本金属学会誌　76　(4)　278　2012

    DOI： 10.2320/jinstmet.76.278 　

  50. Nd-Fe-B薄膜におけるNd2Fe14B/Nd-Rich界面組織と保磁力 Peer-reviewed

    松浦昌志, 後藤龍太, 手束展規, 杉本諭

    日本金属学会誌　76　(1)　65　2012

    DOI： 10.2320/jinstmet.76.65 　

  51. Correlation between symmetry-selective transport and spin-dependent resonant tunneling in fully epitaxial Cr/ultrathin-Fe/MgO/Fe(001) magnetic tunnel junctions Peer-reviewed

    Tomohiko Niizeki, Hiroaki Sukegawa, Seiji Mitani, Nobuki Tezuka, Koichiro Inomata

    APPLIED PHYSICS LETTERS　99　(18)　182508　2011/10

    DOI： 10.1063/1.3647578 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  52. Transmission Electron Microscopy Study on Nd-Rich Phase at the Surface of Nd2Fe14B Phase in Nd-Fe-B Films Peer-reviewed

    Masashi Matsuura, Ryota Goto, Nobuki Tezuka, Satoshi Sugimoto

    IEEE TRANSACTIONS ON MAGNETICS　47　(10)　3273-3275　2011/10

    DOI： 10.1109/TMAG.2011.2148111 　

    ISSN： 0018-9464

  53. Electrical Transport Properties and Spin Injection in Co2FeAl0.5Si0.5/GaAs Junctions Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Satoshi Sugimoto

    IEEE TRANSACTIONS ON MAGNETICS　47　(10)　2447-2450　2011/10

    DOI： 10.1109/TMAG.2011.2153189 　

    ISSN： 0018-9464

  54. Microwave Absorption Properties of Polymer Modified Ni-Zn Ferrite Nanoparticles Peer-reviewed

    Kazuaki Shimba, Kiyotaka Furuta, Nobuyuki Morimoto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　52　(4)　740-745　2011/04

    DOI： 10.2320/matertrans.MBW201013 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  55. Magnetoresistance effect of tunnel junctions using Co-2(Ti, Mn)Z (Z = Al, Si) Heusler alloys Peer-reviewed

    A. Sasaki, N. Tezuka, L. Jiang, S. Sugimoto

    JOURNAL OF APPLIED PHYSICS　109　(7)　07C736　2011/04

    DOI： 10.1063/1.3556778 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  56. Magnetic Properties of Nanoparticle-Polymer Composites Prepared Using Surface Modification and Cross-Linking Reaction Peer-reviewed

    Kazuaki Shimba, Kiyotaka Furuta, Nobuyuki Morimoto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　52　(3)　486-490　2011/03

    DOI： 10.2320/matertrans.MAW201020 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  57. Structural and Magnetic Properties of Co2FeAl0.5Si0.5 Full-Heusler Alloy Thin Films on GaAs Substrates Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　52　(3)　370-373　2011/03

    DOI： 10.2320/matertrans.MBW201004 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  58. Structural and Magnetic Properties of Co2FeAl0.5Si0.5 Full-Heusler Alloy Thin Films Deposited on Si Substrates by Molecular Beam Epitaxy Peer-reviewed

    Tatsuya Saito, Ken Kano, Nobuki Tezuka, Satoshi Sugimoto

    JOURNAL OF THE JAPAN INSTITUTE OF METALS　75　(3)　141-145　2011/03

    DOI： 10.2320/jinstmet.75.141 　

    ISSN： 0021-4876

    eISSN： 1880-6880

  59. MBEによりSi基板上に成膜されたCo2FeAl0.5Si0.5薄膜の結晶構造と磁気特性 Peer-reviewed

    Tatsuya Saito, Nobuki Tezuka, Satoshi Sugimoto

    日本金属学会誌　75　(3)　141　2011

    DOI： 10.2320/jinstmet.75.141 　

  60. Spin injection and detection between CoFe/AlOx junctions and SOI investigates by Hanle effect measurements Peer-reviewed

    TTT

    JOURNAL OF THE JAPAN INSTITUTE OF METALSfff　75　141-145　2011

  61. Influence of Nd Oxide Phase on the Coercivity of Nd-Fe-B Thin Films Peer-reviewed

    Masashi Matsuura, Ryota Goto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　51　(10)　1901-1904　2010/10

    DOI： 10.2320/matertrans.MAW201019 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  62. 溶融硝酸鉄の還元による窒化鉄Fe16N2 微粒子の作製 Peer-reviewed

    榛葉和晃, 手束展規, 杉本 諭

    日本金属学会誌　74　(3)　209-213　2010/03

    DOI： 10.2320/jinstmet.74.209 　

  63. Coフェライト複合ナノ粒子の作製 Peer-reviewed

    深町七奈, 手束展規, 杉本諭

    日本金属学会誌　74　(6)　2010

    DOI： 10.2320/jinstmet.74.345 　

  64. 表面修飾された磁性ナノ粒子によるナノコンポジット粉末の作製 Peer-reviewed

    榛葉和晃, 深町七奈, 手束展規, 杉本諭

    電気学会研究会資料 MAGマグネティックス研究会　71　2010

  65. Microstructural Evaluation of Nd-Fe-B Jet-Milled Powders Peer-reviewed

    Takashi Hattori, Hiroki Ishihara, Satoshi Sugimoto, Ryota Goto, Nobuki Tezuka, Yasuhiro Une, Masato Sagawa

    MATERIALS TRANSACTIONS　50　(10)　2347-2350　2009/10

    DOI： 10.2320/matertrans.MAW200915 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  66. Magnetoresistance Effect of Magnetic Tunnel Junction with Co2Ti0.5Mn0.5Al Full-Heusler Alloy Thin Film Peer-reviewed

    佐々木陽光, 手束展規, 杉本 諭, 大久保亮成, 梅津理恵, 貝沼亮介

    日本金属学会誌　73　(9)　2009/09

    DOI： 10.2320/jinstmet.73.670 　

  67. Influences of Oxidation State of Nd-Rich Phase on the Coercivity of Nd-Fe-B/Nd Thin Films Peer-reviewed

    Masashi Matsuura, Togo Fukada, Ryota Goto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　50　(9)　2139-2142　2009/09

    DOI： 10.2320/matertrans.MAW200913 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  68. Effect of Cu Addition on the Phase Equilibria in Nd-Fe-B Sintered Magnets Peer-reviewed

    Shota Nishio, Satoshi Sugimoto, Ryota Goto, Masashi Matsuura, Nobuki Tezuka

    MATERIALS TRANSACTIONS　50　(4)　723-726　2009/04

    DOI： 10.2320/matertrans.MBW200824 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  69. Interfacial state and magnetic properties of Nd-Fe-B/Nd thin films Peer-reviewed

    Masashi Matsuura, Satoshi Sugimoto, Ryota Goto, Nobuki Tezuka

    JOURNAL OF APPLIED PHYSICS　105　(7)　07A741-1-07A741-3　2009/04

    DOI： 10.1063/1.3076050 　

    ISSN： 0021-8979

  70. The Magnetoresistance of Fe/MgO/GaAs/MgO/Fe Junctions Peer-reviewed

    Fuminori Mitsuhash, Nobuki Tezuka, Satoshi Sugimoto

    JOURNAL OF THE JAPAN INSTITUTE OF METALS　73　(4)　251-254　2009/04

    DOI： 10.2320/jinstmet.73.251 　

    ISSN： 0021-4876

    eISSN： 1880-6880

  71. Improved tunnel magnetoresistance of magnetic tunnel junctions with Peer-reviewed

    N. Tezuka, N. Ikeda, F. Mitsuhashi, S. Sugimoto

    APPLIED PHYSICS LETTERS　94　162504-1-162504-3　2009/04

    DOI： 10.1063/1.3116717 　

  72. Microstructural Evaluation of Nd-Fe-B Strip Cast Alloys Peer-reviewed

    Takashi Hattori, Nana Fukamachi, Ryota Goto, Nobuki Tezuka, Satoshi Sugimoto

    MATERIALS TRANSACTIONS　50　(3)　479-482　2009/03

    DOI： 10.2320/matertrans.MBW200821 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  73. Tunnel magnetoresistance for magnetic tunnel junctions with Co2FeAl0.5Si0.5 Peer-reviewed

    N. Tezuka, N. Ikeda, F. Mitsuhashi, S. Sugimoto

    JOURNAL OF APPLIED PHYSICS　105　07C925-1-07C925-3　2009

    DOI： 10.1063/1.3072448 　

  74. Wettability and Interfacial Microstructure Between Nd2Fe14B and Nd-Rich Phases in Nd-Fe-B Alloys Peer-reviewed

    Ryota Goto, Shota Nishio, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto

    IEEE TRANSACTIONS ON MAGNETICS　44　(11)　4232-4234　2008/11

    DOI： 10.1109/TMAG.2008.2001544 　

    ISSN： 0018-9464

  75. Site disorder in Co2Fe(Al,Si) Heusler alloys and its influence on junction tunnel magnetoresistance Peer-reviewed

    K. Inomata, M. Wojcik, E. Jedryka, N. Ikeda, N. Tezuka

    PHYSICAL REVIEW B　77　(21)　214425-1-214425-9　2008/06

    DOI： 10.1103/PhysRevB.77.214425 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  76. Energy barrier and reversal mechanism in Co/Pt multilayer nanodot Peer-reviewed

    S. Okamoto, T. Kato, N. Kikuchi, O. Kitakami, N. Tezuka, S. Sugimoto

    JOURNAL OF APPLIED PHYSICS　103　(7)　07C501-1-07C501-3　2008/04

    DOI： 10.1063/1.2831785 　

    ISSN： 0021-8979

  77. Magnetization reversal process and bistability of Co/Pt multilayer dot Peer-reviewed

    N. Kikuchi, T. Kato, S. Okamoto, O. Kitakami, N. Tezuka, S. Sugimoto

    JOURNAL OF APPLIED PHYSICS　103　(7)　07C510-1-07C510-3　2008/04

    DOI： 10.1063/1.2838288 　

    ISSN： 0021-8979

  78. Enhanced tunnel magnetoresistance due to spin dependent quantum well resonance in specific symmetry states of an ultrathin ferromagnetic electrode Peer-reviewed

    Tomohiko Niizeki, Nobuki Tezuka, Koichiro Inomata

    PHYSICAL REVIEW LETTERS　100　(4)　047207-1-047207-4　2008/02

    DOI： 10.1103/PhysRevLett.100.047207 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  79. Nd-Fe-B系合金におけるNd2Fe14B相とNd-rich相間の濡れ性 Peer-reviewed

    西尾翔太, 後藤龍太, 松浦昌志, 手束展規, 杉本 諭

    日本金属学会誌　72　(12)　1010-1014　2008

    DOI： 10.2320/jinstmet.72.1010 　

  80. Highly spin-polarized materials and devices for spintronics Peer-reviewed

    Koichiro Inomata, Naomichi Ikeda, Nobuki Tezuka, Ryogo Goto, Satoshi Sugimoto, Marek Wojcik, Eva Jedryka

    SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS　9　(1)　014101　2008/01

    DOI： 10.1088/1468-6996/9/1/014101 　

    ISSN： 1468-6996

    eISSN： 1878-5514

  81. Fabrication and characterization of Co-ferrite thin films for a ferromagnetic barrier in a spin-filtering device operating at room temperature Peer-reviewed

    R. Goto, Y. K. Takahashi, N. Tezuka, K. Inomata, S. Sugimoto, K. Hono

    IEEE TRANSACTIONS ON MAGNETICS　43　(6)　2797-2799　2007/06

    DOI： 10.1109/TMAG.2007.893696 　

    ISSN： 0018-9464

  82. Transmission electron microscopy of Co-2(Cr1-xFex)Al sputtered films and their magnetic tunneling junctions Peer-reviewed

    Y. K. Takahashi, T. Ohkubo, K. Hono, S. Okamura, N. Tezuka, K. Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　313　(2)　378-382　2007/06

    DOI： 10.1016/j.jmmm.2006.09.023 　

    ISSN： 0304-8853

  83. Giant tunnel magnetoresistance at room temperature for junctions using full-heusler Co2FeAl0.5Si0.5 electrodes Peer-reviewed

    Nobuki Tezuka, Naomichi Ikeda, Satoshi Sugimoto, Koichiro Inomata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS　46　(17-19)　L454-L456　2007/05

    DOI： 10.1143/JJAP.46.L454 　

    ISSN： 0021-4922

  84. Tunnel magnetoresistance in magnetic tunnel junctions with Co2Fe (Al, Si) full-Heusler films Peer-reviewed

    N. Tezuka, N. Ikeda, A. Miyazaki, S. Okamura, M. Kikuchi, S. Sugimoto, K. Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　1940-1942　2007/03

    DOI： 10.1016/j.jmmm.2006.10.812 　

    ISSN： 0304-8853

  85. Preparation of Fe/Ni-Zn-Cu ferrite stacked films by aerosol deposition method Peer-reviewed

    S. Sugimoto, V. Chan, M. Noguchi, N. Tezuka, K. Inomata, J. Akedo

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　310　(2)　2549-2551　2007/03

    DOI： 10.1016/j.jmmm.2006.11.146 　

    ISSN： 0304-8853

  86. Coercivity and microstructure of Mn-Ni-N sintered alloys Invited Peer-reviewed

    S. Sugimoto, K. Isogai, T. Hattori, H. Matsumoto, S. Yoshida, N. Tezuka

    Phys. Stat. Sol.　4　4573-4576　2007

    DOI： 10.1002/pssc.200777401 　

  87. プラズマ酸化法により作製したCoフェライト薄膜の構造と磁気特性 Peer-reviewed

    後藤龍太, 高橋有紀子, 中村新一, 手束展規, 猪俣浩一郎, 杉本諭, 宝野和博

    日本応用磁気学会誌　31　(4)　351-355　2007

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.31.351 　

    ISSN： 0285-0192

    More details Close

    For the development of room temperature spin-filtering devices with a ferromagnetic barrier, very thin ferromagnetic barrier films were required. Co-ferrite thin films are prepared by the surface plasma oxidization of a CoFe2 underlayer deposited on MgO (001) single crystal substrates. During oxidization, the substrate temperature was varied from 523 K to 673 K. The plasma oxidized CoFe2 films had a spinel structure, 4-fold symmetry in the plane, and an epitaxial relationship with the CoFe2 underlayer. The lattice parameter of Co-ferrite thin film was 0.828 nm, which is 1.2% less than that of bulk. The interface between the CoFe2 and its oxide was relatively smooth. When the substrate temperature during plasma oxidization was lower than 623 K, magnetization of CoFe2 and Co-ferrite rotated independently. XPS and MOKE measurements identified that the hard and soft phases as Co-ferrite and CoFe2, respectively. Measurements of the magnetic properties showed that the magnetization of the Co-ferrite thin films was about 1100 emu/cm3, which is 2.6 times more than that of bulk (420 emu/cm3). This phenomenon may be explained by the exchange of Co and Fe cation distribution in our Co-ferrite films.

  88. プラズマ酸化法により作製したCoフェライト薄膜の構造、磁気およびバリア特性 Peer-reviewed

    後藤龍太, 高橋有紀子, 手束展規, 猪俣浩一郎, 杉本諭, 宝野和博

    日本金属学会誌　2007

    DOI： 10.2320/jinstmet.71.258 　

  89. Current-driven resistance oscillation in exchange-biased spin valves with a low aspect ratio Peer-reviewed

    Y. Jiang, N. Tezuka, K. Inomata

    APPLIED PHYSICS LETTERS　89　(12)　122514-1-122514-3　2006/09

    DOI： 10.1063/1.2356376 　

    ISSN： 0003-6951

  90. Tunnel magnetoresistance for junctions with epitaxial full-Heusler Co2FeAl0.5Si0.5 electrodes with B2 and L2(1) structures Peer-reviewed

    N. Tezuka, N. Ikeda, A. Miyazaki, S. Sugimoto, M. Kikuchi, K. Inomata

    APPLIED PHYSICS LETTERS　89　(11)　112514-1-112514-3　2006/09

    DOI： 10.1063/1.2354026 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  91. Spin polarization of Co2FeSi full-Heusler alloy and tunneling magnetoresistance of its magnetic tunneling junctions Peer-reviewed

    Z. Gercsi, A. Rajanikanth, Y. K. Takahashi, K. Hono, M. Kikuchi, N. Tezuka, K. Inomata

    APPLIED PHYSICS LETTERS　89　(8)　082512-1-082512-3　2006/08

    DOI： 10.1063/1.2338025 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  92. Indirect exchange spring between FePt and Fe with a Ru interlayer Peer-reviewed

    J Jiang, N Tezuka, K Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　302　(1)　40-46　2006/07

    DOI： 10.1016/j.jmmm.2005.08.009 　

    ISSN： 0304-8853

  93. Structural dependence of the tunnel magnetoresistance for magnetic tunnel junctions with a full-Heusler Co2Fe(Al,Si) electrode Peer-reviewed

    N. Tezuka, S. Okamura, A. Miyazaki, M. Kikuchi, K. Inomata

    JOURNAL OF APPLIED PHYSICS　99　(8)　08T314 -1-08T314 -3　2006/04

    DOI： 10.1063/1.2167069 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  94. Structural and magnetic properties and tunnel magnetoresistance for Co-2(Cr,Fe)Al and Co2FeSi full-Heusler alloys Peer-reviewed

    K Inomata, S Okamura, A Miyazaki, M Kikuchi, N Tezuka, M Wojcik, E Jedryka

    JOURNAL OF PHYSICS D-APPLIED PHYSICS　39　(5)　816-823　2006/03

    DOI： 10.1088/0022-3727/39/5/S07 　

    ISSN： 0022-3727

    eISSN： 1361-6463

  95. Quantum oscillation of the tunneling conductance in fully epitaxial double barrier magnetic tunnel junctions Peer-reviewed

    T Nozaki, N Tezuka, K Inomata

    PHYSICAL REVIEW LETTERS　96　(2)　027208-1-027208-4　2006/01

    DOI： 10.1103/PhysRevLett.96.027208 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  96. ナノドットFe中間層を有するエピタキシャル強磁性２重トンネル接合におけるコンダクタンスの振動現象 Peer-reviewed

    野崎 隆行, 中村 新一, 手束 展規, 杉本 諭, 猪俣 浩一郎

    日本応用磁気学会誌　30　(2)　180-183　2006

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.30.180 　

    ISSN： 0285-0192

    More details Close

    Double-barrier magnetic tunnel junctions (DMTJs) with an Fe(001) / MgO(001) / Fe(001) / MgO(001) / Fe(001) structure were deposited upon MgO(001) substrates by using molecular beam epitaxy. The DMTJs were found to show the TMR ratio of up to 110% and an extremely small bias voltage dependence (V1/2 = 1.4 V under a positive bias application) at room temperature. We also investigated the middle-layer thickness dependence of the conductance curve in the DMTJs. Clear oscillations of the conductance were observed in a parallel magnetization configuration. This oscillation is thought to originate in the modulation of the tunneling conductance by the spin-polarized quantum well states created in the middle Fe layer.

  97. MgO基板上に作製したCo2V0.67Fe0.33Al薄膜の構造と磁性およびトンネル磁気抵抗 Peer-reviewed

    宮崎彩, 岡村進, 杉本諭, 手束展規, 猪俣浩一郎

    日本応用磁気学会誌　30　(3)　378-382　2006

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.30.378 　

    ISSN： 0285-0192

    More details Close

    Co2V0.67Fe0.33Al full-Heulser alloy films were fabricated on an MgO (100) single crystalline substrate by using two different heat treatments: substrate heating and post-annealing. Ultra-high-vacuum dc magnetron sputtering was used to prepare the sample. The L21 structure was obtained when the substrate temperature (Ts) was 500°C. For the same sample, the magnetic moment per formula unit showed the highest value of 2.4 μB at 5 K. There were small differences between the samples fabricated by substrate heating and post-annealing in terms of their structural and magnetic properties. A magnetic tunnel junction (MTJ) using Co2V0.67Fe0.33Al as a bottom electrode was fabricated. A larger tunnel magnetoresistance (TMR) was obtained by substrate heating than post-annealing with a maximum value of 28% at RT and 50% at 5 K when the Co2V0.67Fe0.33Al was sputtered at Ts = 500°C. We found that there is an intimate relationship between the lattice constant of Co2V0.67Fe0.33Al and the TMR.

  98. 不規則構造を有するCo2(Cr1-xFex)Alを用いた強磁性トンネル接合のTMR特性 Peer-reviewed

    岡村進, 宮崎彩, 手束展規, 杉本諭, 猪俣浩一郎, 高橋有紀子, 宝野和博

    日本応用磁気学会誌　30　(3)　366-369　2006

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.30.366 　

    More details Close

    Polycrystalline and single crystalline thin films of Co2(Cr1-xFex)Al (x = 0.6, 1) full-Heusler alloys with different disordering were prepared on thermally oxidized Si and MgO(001) substrates, respectively, by the dc magnetron sputtering method. The magnetic tunnel junctions with a polycrystalline and single crystalline B2 type Co2FeAl (x =1) electrode demonstrate TMR of 70% and 75% at 5 K, respectively, which is larger than that of 65% at 5 K for Co75Fe25, indicating that the spin polarization for Co2FeAl is larger than that for Co75Fe25. The TMR for Co2FeAl with both the A2 and the B2, which is controlled by substrate heating, is almost the same, whereas for Co2(Cr0.4Fe0.6)Al the TMR increases with increasing the degree of ordering, corresponding to the first-principles calculations.

  99. 不規則構造を有するCo2(Cr1-xFex)Alフルホイスラー合金を用いた強磁性トンネル接合の磁気抵抗効果 Peer-reviewed

    岡村進, 宮崎彩, 手束展規, 杉本諭, 猪俣浩一郎, 高橋有紀子, 宝野和博

    電気学会論文誌A　126　276-280　2006

    DOI： 10.1541/ieejfms.126.276 　

  100. エアロゾル・デポジッション法により作製したFe/Ni-Zn-Cuフェライト複合膜における組成制御と電磁ノイズ抑制効果 Peer-reviewed

    チャンビサル, 杉本諭, 猪俣浩一郎, 手束展規, 明度純

    日本応用磁気学会誌　30　(5)　505-509　2006

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.30.505 　

    ISSN： 0285-0192

  101. L21構造を持つCo2CrGaフルホイスラー合金薄膜の作製とそれを用いた強磁性トンネル接合素子のトンネル磁気抵抗 Peer-reviewed

    正木達章, 菊地麻樹, 手束展規, 杉本諭, 猪俣浩一郎, 貝沼亮介, 石田清仁

    日本応用磁気学会誌　30　(4)　455-458　2006

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.30.455 　

    ISSN： 0285-0192

    More details Close

    We have investigated that the structural and magnetic properties of Co2CrGa full-Heusler alloy films and researched the tunnel magnetoresistance (TMR) in magnetic tunnel junctions (MTJs) using a Co2CrGa electrode on a MgO(100) substrate. Co2CrGa films were fabricated with substrate heating (RT ≤ Ts ≤ 500°C) or post-annealing (RT ≤ Ta ≤ 500°C) after the deposition using an ultrahigh vacuum dc magnetron sputtering system. L21-ordered Co2CrGa thin films were obtained at Ts ≥ 300°C or Ta ≥ 200°C. The maximum magnetic moment per formula unit measured at 5 K were 2.8 μB and 2.6 μB for TS and Ta = 400°C, respectively, which are over 85% of the theoretical value. The maximum TMR of 18% at RT and 42% at 5 K are obtained for the MTJ using the L21-structured Co2CrGa film as a bottom electrode. It is expected that the TMR can be enhanced by optimizing the interface of Co2CrGa/AlOx.

  102. Magnetic properties of epitaxial Co2Cr1-xFexAl full Heusler alloy thin films with the L2(1) structure Peer-reviewed

    A Hirohata, H Kurebayashi, S Okamura, N Tezuka, K Inomata

    IEEE TRANSACTIONS ON MAGNETICS　41　(10)　2802-2804　2005/10

    DOI： 10.1109/TMAG.2005.854831 　

    ISSN： 0018-9464

    eISSN： 1941-0069

  103. Magnetic transport mechanism in double ferromagnetic tunnel junctions with two-dimensional ferromagnetic particles Peer-reviewed

    H Sukegawa, A Hirohata, S Nakamura, N Tezuka, S Sugimoto, K Inomata

    IEEE TRANSACTIONS ON MAGNETICS　41　(10)　2679-2681　2005/10

    DOI： 10.1109/TMAG.2005.855292 　

    ISSN： 0018-9464

  104. Exchange coupling between FePt and Fe through Ru interlayer Peer-reviewed

    JH Jiang, N Tezuka, K Inomata

    JOURNAL OF APPLIED PHYSICS　98　(6)　063902-1-063902-3　2005/09

    DOI： 10.1063/1.2058189 　

    ISSN： 0021-8979

  105. Large tunnel magnetoresistance at room temperature with a Co2FeAl full-Heusler alloy electrode Peer-reviewed

    S Okamura, A Miyazaki, S Sugimoto, N Tezuka, K Inomata

    APPLIED PHYSICS LETTERS　86　(23)　232503-1-232503-3　2005/06

    DOI： 10.1063/1.1944893 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  106. Distinctive current-induced magnetization switching in a current-perpendicular-to-plane giant-magnetoresistance nanopillar with a synthetic antiferromagnet free layer Peer-reviewed

    T Ochiai, Y Jiang, A Hirohata, N Tezuka, S Sugimoto, K Inomata

    APPLIED PHYSICS LETTERS　86　(24)　242506-1-242506-3　2005/06

    DOI： 10.1063/1.1949709 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  107. Structural and magnetic properties of epitaxial L2(1)-structured Co-2(CrFe)Al films grown on GaAs(001) substrates Peer-reviewed

    A Hirohata, H Kurebayashi, S Okamura, M Kikuchi, T Masaki, T Nozaki, N Tezuka, K Inomata

    JOURNAL OF APPLIED PHYSICS　97　(10)　103714-1-103714-8　2005/05

    DOI： 10.1063/1.1888050 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  108. Spin transfer in antisymmetric exchange-biased spin-valves Peer-reviewed

    Y Jiang, GH Yu, YB Wang, J Teng, T Ochiai, N Tezuka, K Inomata

    APPLIED PHYSICS LETTERS　86　(19)　192515-1-192515-3　2005/05

    DOI： 10.1063/1.1927694 　

    ISSN： 0003-6951

  109. CPP-GMR enhancement in spin valves using a thin Ru layer Peer-reviewed

    N Tezuka, S Abe, Y Jiang, K Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　290　1150-1153　2005/04

    DOI： 10.1016/j.jmmm.2004.11.499 　

    ISSN： 0304-8853

  110. Significant magnetoresistance enhancement due to a cotunneling process in a double tunnel junction with single discontinuous ferromagnetic layer insertion Peer-reviewed

    H Sukegawa, S Nakamura, A Hirohata, N Tezuka, K Inomata

    PHYSICAL REVIEW LETTERS　94　(6)　068304-1-068304-4　2005/02

    DOI： 10.1103/PhysRevLett.94.068304 　

    ISSN： 0031-9007

  111. Bias voltage effect on tunnel magnetoresistance in fully epitaxial MgO double-barrier magnetic tunnel junctions Peer-reviewed

    T Nozaki, A Hirohata, N Tezuka, S Sugimoto, K Inomata

    APPLIED PHYSICS LETTERS　86　(8)　082501-1-082501-3　2005/02

    DOI： 10.1063/1.1867559 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  112. Magnetic properties of L21-structured Co2(Cr,Fe)Al films grown on GaAs(001) substrates Peer-reviewed

    A. Hirohata, H. Kurebayashi, S. Okamura, T. Masaki, T. Nozaki, M. Kikuchi, N. Tezuka, K. Inomata, J.S. Claydon, Y.B. Xu

    JOURNAL OF APPLIED PHYSICS　97　10C308-1-10C308-3　2005

    DOI： 10.1063/1.1854256 　

  113. L21構造を有するCo2Cr1-xFexAl薄膜の結晶構造と磁気特性 Peer-reviewed

    廣畑 貴文, 紅林 秀和, 岡村 進, 菊地 麻樹, 正木 達章, 野崎 隆行, 手束 展規, 猪俣 浩一郎

    日本応用磁気学会誌　29　(2)　124-127　2005

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.29.124 　

    ISSN： 0285-0192

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    We successfully grew Co2Cr1-xFexAl full Heusler films (0 ≤ x ≤ 1) with the L21 structure onto GaAs(001) substrates by achieving stoichiometry in an ultrahigh-vacuum molecular beam epitaxy chamber. The films develop epitaxial crystallinity with the relationship of Co2Cr1-xFexAl(001)‹110›||GaAs(001)‹110›, which induces very strong uniaxial magnetocrystalline anisotropy, except for x = 0. For x = 1, in particular, the film is almost a single phase and its magnetic moment per formula unit exhibits Slater-Pauling behavior. Films of this type were used to fabricate magnetic tunnel junctions with 8.8% and 4.9% tunnel magnetoresistance (TMR) ratios at room temperature for x = 1 with an Al-O tunnel barrier and x = 0.6 with a MgO barrier, respectively. The TMR ratio can be further enhanced by both realizing an L21 single phase and eliminating lattice distortion.

  114. 強磁性ナノドット層を有する二重トンネル接合におけるTMRの増大 Peer-reviewed

    介川 裕章, 中村 新一, 廣畑 貴文, 手束 展規, 猪俣 浩一郎, 杉本 諭

    日本応用磁気学会誌　29　(3)　274-277　2005

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.29.274 　

    ISSN： 0285-0192

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    We observed spin-dependent tunneling in Co90Fe10/AlOx/Co90Fe10/AlOx/Co90Fe10 ferromagnetic double tunnel junctions. A middle Co90Fe10 layer, which is inserted between two AlOx layers, is discontinuous due to the difference in the surface energy of these layers. The average diameter of Co90Fe10 particles was estimated to be 2.0-4.5 nm from cross-sectional transmission electron microscopy (TEM) images. At low temperature (< 50 K), a Coulomb gap is observed in current-voltage (I-V) curves, and the tunnel magnetoresistance (TMR) ratio within the gap enhances significantly with decreasing temperature, which indicates that the dominant electron transport is inelastic co-tunneling within the Coulomb gap. These observations in a ferromagnetic tunnel junction with 2-dimensional magnetic nano-particle layer insertion accord well with theoretical predictions by Takahashi and Maekawa [Phys. Rev. Lett. 80, 1758 (1998)].

  115. Co2CrGaフルホイスラー合金薄膜の結晶構造と磁気・電気伝導特性 Peer-reviewed

    菊地 麻樹, 正木 達章, 手束 展規, 杉本 諭, 猪俣 浩一郎

    日本応用磁気学会誌　29　(4)　455-458　2005

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.29.455 　

    ISSN： 0285-0192

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    We investigated the structural, magnetic and electrical transport properties of Co2CrGa full Heusler alloy films, and optimized the growth conditions, achieving stoichiometric films. The crystalline structures and the magnetic and electrical transport properties were found to depend on the film thickness, tCCG. An ordered L21 structure was obtained for tCCG≥100 nm. The saturation magnetization decreases with decreasing film thickness and vanishes below tCCG=23 nm, indicating the existence of a magnetically dead layer in the vicinity of the substrates. For tCCG=150 nm, the saturation magnetization is 602 emu/cm3 (3.1 μB) at 5 K, which agrees very well with the theoretical value. The resistivity of the samples with tCCG≤150 nm decreases with increasing temperature, while that with tCCG=300 nm increases. By using films with tCCG=100 nm and 300 nm as bottom electrodes, forming an L21 structure, magnetic tunnel junctions (MTJs) were also fabricated, showing 5.0% and 1.4% tunnel magnetoresistance (TMR) at RT, respectively.

  116. Structural, magnetic, and transport properties of full-Heusler alloy Co-2(Cr1-xFex)Al thin films Peer-reviewed

    S Okamura, R Goto, S Sugimoto, N Tezuka, K Inomata

    JOURNAL OF APPLIED PHYSICS　96　(11)　6561-6564　2004/12

    DOI： 10.1063/1.1810207 　

    ISSN： 0021-8979

  117. Tunnel magneto resistance using full-Heusler alloys Peer-reviewed

    K Inomata, S Okamura, N Tezuka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　282　269-274　2004/11

    DOI： 10.1016/j.jmmm.2004.04.063 　

    ISSN： 0304-8853

    eISSN： 1873-4766

  118. Spin-dependent quantum oscillations in magnetic tunnel junctions with Ru quantum wells Peer-reviewed

    T Nozaki, Y Jiang, Y Kaneko, A Hirohata, N Tezuka, S Sugimoto, K Inomata

    PHYSICAL REVIEW B　70　(17)　172401-172401　2004/11

    DOI： 10.1103/PhysRevB.70.172401 　

    ISSN： 1098-0121

  119. Effect of the soft/hard exchange interaction on natural resonance frequency and electromagnetic wave absorption of the rare earth-iron-boron compounds Peer-reviewed

    T Maeda, S Sugimoto, T Kagotani, N Tezuka, K Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　281　(2-3)　195-205　2004/10

    DOI： 10.1016/j.jmmm.2004.04.105 　

    ISSN： 0304-8853

  120. Influence of synthetic antiferromagnet free layer on current-perpendicular-to-plane spin-valves Peer-reviewed

    Y Jiang, S Abe, T Nozaki, N Tezuka, K Inomata

    IEEE TRANSACTIONS ON MAGNETICS　40　(4)　2245-2247　2004/07

    DOI： 10.1109/TMAG.2004.830231 　

    ISSN： 0018-9464

  121. Magnetoresistance in tunnel junctions using Co-2(Cr,Fe)Al full Heusler alloys Peer-reviewed

    K Inomata, N Tezuka, S Okamura, H Kurebayashi, A Hirohata

    JOURNAL OF APPLIED PHYSICS　95　(11)　7234-7236　2004/06

    DOI： 10.1063/1.1651813 　

    ISSN： 0021-8979

    eISSN： 1089-7550

  122. Substantial reduction of critical current for magnetization switching in an exchange-biased spin valve Peer-reviewed

    Y Jiang, T Nozaki, S Abe, T Ochiai, A Hirohata, N Tezuka, K Inomata

    NATURE MATERIALS　3　(6)　361-364　2004/06

    DOI： 10.1038/nmat1120 　

    ISSN： 1476-1122

    eISSN： 1476-4660

  123. Magnetic domain structures and switching properties in submicron size synthetic antiferromagnets Peer-reviewed

    N. Tezuka, N. Koike, K. Sakurada, K. Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　272　E1289-E1291　2004/05

    DOI： 10.1016/j.jmmm.2003.12.403 　

    ISSN： 0304-8853

  124. Magnetic switching properties of magnetic tunnel junctions using a synthetic ferrimagnet free layer Peer-reviewed

    T Nozaki, Y Jiang, H Sukegawa, N Tezuka, A Hirohata, K Inomata, S Sugimoto

    JOURNAL OF APPLIED PHYSICS　95　(7)　3745-3748　2004/04

    DOI： 10.1063/1.1669053 　

    ISSN： 0021-8979

  125. Effective reduction of critical current for current-induced magnetization switching by a Ru layer insertion in an exchange-biased spin valve Peer-reviewed

    Y Jiang, S Abe, T Ochiai, T Nozaki, A Hirohata, N Tezuka, K Inomata

    PHYSICAL REVIEW LETTERS　92　(16)　167204-1-167204-4　2004/04

    DOI： 10.1103/PhysRevLett.92.167204 　

    ISSN： 0031-9007

  126. Co2Cr1-xFexAlフルホイスラー合金の構造と磁気・伝導特性 Peer-reviewed

    岡村進, 後藤龍太, 手束展規, 杉本諭, 猪俣浩一郎

    日本金属学会誌　68　114-117　2004

    DOI： 10.2320/jinstmet.68.114 　

  127. Zn0.4Fe2.6O4薄膜を用いた強磁性トンネル接合の磁気抵抗効果 Peer-reviewed

    西村和正, 手束展規, 杉本諭, 猪俣浩一郎

    日本金属学会誌　68　81-85　2004

    DOI： 10.2320/jinstmet.68.82 　

  128. スピン二重トンネル接合の磁気抵抗効果 Peer-reviewed

    介川裕章, 手束展規, 猪俣浩一郎, 杉本諭

    日本金属学会誌　68　74-77　2004

    DOI： 10.2320/jinstmet.68.74 　

  129. Co2(Cr1-xFex)Alフルホイスラー合金を用いたMTJの磁気抵抗効果 Peer-reviewed

    岡村 進, 後藤龍太, 手束展規, 杉本 諭, 猪俣浩一郎

    日本応用磁気学会誌　28　(2)　172-175　2004

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.28.172 　

    ISSN： 0285-0192

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    Co2CrAl (x = 0) films were found to form a B2 structure, and when Fe was substituted for Cr (x = 0.4−0.6), the films crystallized B2+A2 structures, while an A2 structure was stable in the case of Co2FeAl (x = 1) films deposited on thermally oxidized Si substrates at room temperature. The magnetic moments of the films containing Fe tended to increase with increasing x, while those of the films containing Cr were far from the values calculated with an assumption of the L21 structure ordering.<BR>Spin-valve-type tunneling junctions with a Co2(Cr1-xFex) Al film were also fabricated, which demonstrated large tunneling magnetoresistance of 19.1% (x= 0.4) at room temperature and 27.2% at 5 K in spite of atomic site disorder.

  130. 極薄Ruキャップ層を用いたスピンバルブ素子のCPP-GMR特性 Peer-reviewed

    阿部 慎也, 山口 正彦, 手束 展規, 猪俣 浩一郎

    日本応用磁気学会誌　28　(9)　987-990　2004

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.28.987 　

    ISSN： 0285-0192

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    We have studied the current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) of single spin-valve (SV) films with two different free layers : one is a single ferromagnet layer (conventional), and the other is a ferromagnetic layer with a ruthenium cap layer (Ru cap). When the spacer Cu layer thickness is 2.5 nm and the Ru layer is 0.45 nm, the Ru cap-type greatly enhances the CPP-GMR, with increasing its value up to 4.3%. We argue that the MR enhancement is probably caused by the spin-dependent scattering due to the strong reflection of majority spins at the Co90Fe10/Ru interface.

  131. Enhanced Current-perpendicular-to-plane Giant Magnetoresistance in Single Spin-valve with Synthetic Antiferromagnet Free Layers Peer-reviewed

    Y. Jiang, S. Abe, T. Nozaki, N. Tezuka, K. Inomata

    Transactions of the Materials Research Society of Japan　29　1531-1533　2004

  132. Perpendicular giant magnetoresistance and magnetic switching properties of a single spin valve with a synthetic antiferromagnet as a free layer Peer-reviewed

    Y Jiang, S Abe, T Nozaki, N Tezuka, K Inomata

    PHYSICAL REVIEW B　68　(22)　224426-1-224426-7　2003/12

    DOI： 10.1103/PhysRevB.68.224426 　

    ISSN： 1098-0121

  133. Enhancement of current-perpendicular-to-plane giant magnetoresistance by synthetic antiferromagnet free layers in single spin-valve films Peer-reviewed

    Y Jiang, S Abe, T Nozaki, N Tezuka, K Inomata

    APPLIED PHYSICS LETTERS　83　(14)　2874-2876　2003/10

    DOI： 10.1063/1.1616974 　

    ISSN： 0003-6951

  134. Improved thermal stability of ferromagnetic tunnel junctions with a CoFe/CoFeOX/CoFe pinned layer Peer-reviewed

    T Ochiai, N Tezuka, K Inomata, S Sugimoto, Y Saito

    IEEE TRANSACTIONS ON MAGNETICS　39　(5)　2797-2799　2003/09

    DOI： 10.1109/TMAG.2003.815715 　

    ISSN： 0018-9464

  135. Magnetization reversal and domain structure of antiferromagnetically coupled submicron elements Peer-reviewed

    N Tezuka, N Koike, K Inomata, S Sugimoto

    JOURNAL OF APPLIED PHYSICS　93　(10)　7441-7443　2003/05

    DOI： 10.1063/1.1539074 　

    ISSN： 0021-8979

  136. Size-independent spin switching field using synthetic antiferromagnets Peer-reviewed

    K Inomata, N Koike, T Nozaki, S Abe, N Tezuka

    APPLIED PHYSICS LETTERS　82　(16)　2667-2669　2003/04

    DOI： 10.1063/1.1568823 　

    ISSN： 0003-6951

  137. Large tunneling magnetoresistance at room temperature using a Heusler alloy with the B2 structure Peer-reviewed

    K Inomata, S Okamura, R Goto, N Tezuka

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS　42　(4B)　L419-L422　2003/04

    DOI： 10.1143/JJAP.42.L419 　

    ISSN： 0021-4922

  138. ZnxFe3-xO4薄膜の構造および磁気・電気特性 Peer-reviewed

    西村和正, 手束展規, 猪俣浩一郎, 杉本諭

    日本応用磁気学会誌　27　(4)　340-343　2003

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.27.340 　

    ISSN： 0285-0192

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    The structural, magnetic, and electrical properties of sputtered ZnxFe3-xO4 thin films were investigated. A spinel structure was obtained for samples annealed above 673 K. The magnetization at 10 kOe of a sample sputtered in Ar and annealed at 873 K was 450 emu/cm3. Magnetization decreased in samples annealed above 873 K, as a result of evaporation of Zn and an increase in the thickness of the insulating layer. A MR ratio of about 4.3 % was observed at T = 300 K in a sample sputtered in Ar and O2 mixed gas, and MR curve was of a granular type. However, because the Zn was completely evaporated at this sample, the MR was associated with the Fe3O4 grains and the α-Fe2O3 boundary.

  139. 微細反平行結合素子の磁化状態とスピン反転磁場 Peer-reviewed

    小池伸幸, 手束展規, 猪俣浩一郎, 杉本諭

    日本応用磁気学会誌　27　(4)　316-319　2003

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.27.316 　

    ISSN： 0285-0192

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    Arrays of synthetic antiferromagnetic (SyAF) patterned elements were successfully fabricated with micron to submicron sizes. Their magnetic domain structures and spin-switching fields were investigated by using magnetic force microscopy (MFM) and the magnetic optical Kerr effect (MOKE), respectively. A single-domain structure was observed in Co9Fe/Ru/Co9Fe SyAF bits for even a small aspect ratio of 1, while Co9Fe monolayer bits showed a multi-domain structure for aspect ratios below 2. The spin-switching field of Co9Fe (6 nm)/Ru (0.45 nm)/Co9Fe (10 nm) SyAF exhibited independence of element size, while that of Co9Fe (10 nm) single elements was strongly dependent on element size. These results indicate the predominance of SyAF for ultrahigh-bit-density MRAM devices.

  140. ピン層にCoFe/CoFeOx/CoFeを用いた強磁性トンネル接合の耐熱性の改善 Peer-reviewed

    落合隆夫, 手束展規, 猪俣浩一郎, 杉本諭, 斉藤好昭

    日本応用磁気学会誌　27　(4)　307-310　2003

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.27.307 　

    ISSN： 0285-0192

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    The annealing temperature dependence of the tunnel magnetoresistance (TMR) ratio for ferromagnetic tunnel junctions with CoFeOx inserted in the pinned layer was investigated. A junction with a CoFe/CoFeOx/CoFe as the pinned layer exhibited TMR ratios of 47 % and 43 % after annealing at 350°C and at 375°C respectively, The reason for the improvement of the thermal stability is related to oxygen diffusion from CoFeOx layer, and there is a possibility that CoFeOx plays a role of Mn (in MnIr exchange layer) diffusion barrier.

  141. Single domain observation for synthetic antiferromagnetically coupled bits with low aspect ratios Peer-reviewed

    N Tezuka, N Koike, K Inomata, S Sugimoto

    APPLIED PHYSICS LETTERS　82　(4)　604-606　2003/01

    DOI： 10.1063/1.1539549 　

    ISSN： 0003-6951

  142. Magnetic switching field and giant magnetoresistance effect of multilayers with synthetic antiferromagnet free layers Peer-reviewed

    K Inomata, T Nozaki, N Tezuka, S Sugimoto

    APPLIED PHYSICS LETTERS　81　(2)　310-312　2002/07

    DOI： 10.1063/1.1490149 　

    ISSN： 0003-6951

  143. A thermodynamic study of the HDDR conditions in the Sm2Fe17Nx compound Peer-reviewed

    S Ohga, S Sugimoto, N Tezuka, T Kagotani, K Inomata

    MATERIALS TRANSACTIONS　43　(3)　459-461　2002/03

    DOI： 10.2320/matertrans.43.459 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  144. Magnetic properties and microwave absorption properties of polymer-protected cobalt nanoparticles Peer-reviewed

    Y Kato, S Sugimoto, K Shinohara, N Tezuka, T Kagotani, K Inomata

    MATERIALS TRANSACTIONS　43　(3)　406-409　2002/03

    DOI： 10.2320/matertrans.43.406 　

    ISSN： 1345-9678

    eISSN： 1347-5320

  145. Magnetic properties of the Cr(001) surface studied by spin-polarized scanning tunneling spectroscopy Peer-reviewed

    M Kleiber, M Bode, R Ravlic, N Tezuka, R Wiesendanger

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　240　(1-3)　64-69　2002/02

    ISSN： 0304-8853

  146. Improvement of coercivity of anisotropic Nd-Fe-BHDDR powders by Ga addition Peer-reviewed

    S Sugimoto, H Murai, N Koike, H Nakamura, D Book, N Tezuka, T Kagotani, M Okada, M Homma, K Inomata

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　239　(1-3)　444-446　2002/02

    DOI： 10.1016/S0304-8853(01)00620-5 　

    ISSN： 0304-8853

  147. Switching field behavior in antiparallely coupled sub-micrometer scale magnetic elements Peer-reviewed

    N Tezuka, E Kitagawa, K Inomata, S Sugimoto, N Kikuchi, Y Shimada

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　240　(1-3)　294-296　2002/02

    DOI： 10.1016/S0304-8853(01)00782-X 　

    ISSN： 0304-8853

  148. 反平行結合フリー層を用いたGMRスピンバルブ膜の磁化反転特性 Peer-reviewed

    野崎隆行, 阿部慎也, 手束展規, 猪俣浩一郎, 杉本諭

    日本金属学会誌　66　1078-1082　2002

    DOI： 10.2320/jinstmet1952.66.11_1078 　

  149. Thickness and Oxidation Time Dependence of Tunnel Magnetoresistance in Ni-Fe/Co/Al-O/Co Junctions Peer-reviewed

    H. Kubota, S. Otsuka, M. Kamijo, N. Tezuka, Y. Ando, C.C. Yu, T. Miyazaki

    Journal of the Magnetics Society of Japan　24　(4)　595-598　2000

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.24.595 　

    ISSN： 0285-0192

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    Ni-Fe/Co/Al-O/Co tunnel junctions with small active areas down to 3 x 3 μm2 were fabricated by the micro-fabrication technique. The Al-O insulating layer was prepared by plasma oxidation of a thin sputtered Al film. The dependences of the tunnel magnetoresistance on the thickness of the Al film and the oxidation time were investigated. The interface structure of the junction was observed by using high-resolution electron microscopy. The relationship between the magnetoresistive properties and the interface structure is discussed.

  150. Characterization of the Barrier Layer in Al1-xCox/{ Al1-xCox -Oxide}/Al Tunnel Junctions Peer-reviewed

    X.F. Han, J. Murai, M. Hayashi, N. Tezuka, Y. Ando, T. Miyazaki

    Journal of the Magnetics Society of Japan　24　(4)　603-606　2000

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.24.603 　

    ISSN： 0285-0192

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    Oxides of Al1-xCox (x = 0, 0.25, 0.50, 0.75, and 1.0) alloys were chosen as barrier materials in this work. The tunnel junctions consisted of a bottom electrode Al1-xCox and a top electrode Al with an insulating layer {Al1-xCox-oxide} formed by natural oxidation in a baking-box at 333 K. The oxidation time for forming an Al1-xCox-oxide layer on the surface of the bottom Al1-xCox layers was optimized. When tunnel resistances were between 105 and 107 &Omega;&mu;m2 measured at 1 mV and at 4.2 K, the effective barrier height and width of the insulating layers of Al1-xCox-oxide (x = 0.25, 0.5, and 0.75) varied between 0.7 and 2.2 eV and between 1.4 and 1.7 nm, respectively. It is shown that the thin oxide layer of Al1-xCox alloys can be used as a barrier.

  151. Ni80Fe20/Co/N(N=Ta,Cu,Al)/Al-oxide/Co接合における磁気抵抗効果 Peer-reviewed

    大坊忠臣, 手束展規, 久保田均, 安藤康夫, 林将光, 宮崎照宣, Changkyung Kim, Ohsung Song

    日本応用磁気学会誌　24　(4)　599-602　2000

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.24.599 　

    ISSN： 0285-0192

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    The effect on the tunneling magnetoresistance (TMR) of inserting the nonmagnetic metals (NMs) Al, Cu, and Ta between the insulator and ferromagnetic layer of a tunnel junctions was investigated. The TMR ratio for a junction with Ta decreased rapidly with increasing Ta thickness, while that for a junction with Al remained more than 50 Å of the thickness. From cross-sectional TEM and AFM measurement, it was found that a junction with thick Al has an insulating layer on both sides of the metallic Al; that is, it would be a double-barrier tunnel junction. We compared the experimental result for the metallic Al thickness dependence of the TMR ratio with the theory of double tunnel junctions. Consequently, the spin diffusion length of Al was estimated to be sub-micrometer.

  152. Applied voltage and temperature dependence of tunneling magnetoresistance Peer-reviewed

    N Tezuka, M Oogane, T Miyazaki

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　198-99　149-151　1999/06

    DOI： 10.1016/S0304-8853(98)01056-7 　

    ISSN： 0304-8853

  153. Influence of interlayer roughness on magnetoresistive effect of ferromagnetic tunneling junctions Peer-reviewed

    Y Ando, M Yokota, N Tezuka, T Miyazaki

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　198-99　155-157　1999/06

    DOI： 10.1016/S0304-8853(98)01053-1 　

    ISSN： 0304-8853

  154. Arイオンミリングによる強磁性トンネル接合の微細加工 Peer-reviewed

    大塚茂樹, 上條誠, 手束展規, 久保田均, 宮崎照宣

    日本応用磁気学会誌　23　(4)　1305-1308　1999

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.23.1305 　

    ISSN： 0285-0192

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    The effect of the Ar ion milling process on tunnel magneto-resistance was investigated by using Ar ion milling to make a small hole at the center of the active area of a junction prepared by means of metal masks. Metallic short-circuiting through the material redeposited during Ar ion milling was evaluated by comparing the tunnel resistance before and after the process. The amount of redeposited material was small in the samples produced by the milling process with a higher incident angle of Ar ions. Small Ni-Fe/Co/Al-O/Co junctions with various active area ranged from 9 to 104 μm2 were also fabricated. The tunnel resistance increased in inverse proportion to the active area. Many junctions showed a TMR ratio of 9%-13%, which was as large as the value for junctions prepared by means of metal masks.

  155. 強磁性体/Al－Oxide/Co接合のトンネル磁気抵抗効果の印加電圧及び温度依存性 Peer-reviewed

    大兼幹彦, 手束展規, 宮崎照宣

    日本応用磁気学会誌　23　(4)　1297-1300　1999

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.23.1297 　

    ISSN： 0285-0192

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    Ferromagnetic tunneling junctions with various thicknesses of the first ferromagnetic layer were fabricated. Co and Ni80Fe20 were used as the first ferromagnetic layer, and their thicknesses were varied between 10 and 200 Å. The voltage and temperature dependence of the tunneling magnetoresistance (TMR) ratio and conductance characteristic were investigated for these junctions. A drastic decrease in the conductance near the zero bias in the conductance-voltage characteristics (zero-bias anomaly) was observed in some junctions. A rapid decrease in the TMR ratio below 5 mV and 50 K was also observed in the same junctions. A slight decrease in the TMR ratio above 10 mV and 100 K was observed in all junctions. We investigated the origin of the voltage and temperature dependence of the TMR ratio by taking account of the magnetic impurity and magnon effect.

  156. Ni80Fe20/Al－Oxide/Co接合におけるトンネル磁気抵抗比のNi80Fe20膜厚依存性 Peer-reviewed

    大兼幹彦, 手束展規, 宮崎照宣

    日本応用磁気学会誌　23　(4)　1309-1312　1999

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.23.1309 　

    ISSN： 0285-0192

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    Ferromagnetic tunneling junctions with various thicknesses of the first ferromagnetic layer were fabricated. Ni80Fe20 and Co were used as the first ferro-magnetic layer, and their thicknesses were varied between 10 and 200 Å. The tunneling magnetoresistance (TMR) ratio decreased and the shape of the TMR curve changed with decreasing Ni80Fe20 thickness, but changed only slightly with decreasing Co thickness. We calculated the TMR and magnetization curves by using a simple model that takes account of magnetic anisotropy to explain the change in the TMR ratio and the shape of the TMR curve with changing Ni80Fe20 thickness.

  157. Ni80Fe20/Al-oxide/Co接合における磁気抵抗効果のAl-oxide厚依存性 Peer-reviewed

    手束展規, 宮崎照宣

    日本応用磁気学会誌　23　(4)　1317-1320　1999

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.23.1317 　

    ISSN： 0285-0192

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    Ferromagnetic tunneling junctions of Ni80Fe20/Al oxide/Co with various Ni80Fe20 and Al-oxide thicknesses were fabricated by magnetron sputtering using metal masks. The thicknesses of Ni80Fe20 were 70, 100, 200, 500, and 1000 Å. The thicknesses of the Al layer ranged from 7 to 80 Å, and the Al oxide films were formed by natural oxidization. The thicker the Ni80Fe20 layer, the larger the optimum Al thickness for the TMR ratio. On the other hand, when the thickness of Ni80Fe20 was constant, the TMR ratio decreased with increasing Al thickness. To clarify the reason for this, AFM images of the Ni80Fe20 surface were measured. The surface roughness of Ni80Fe20 increased with increasing Ni80Fe20 thickness.

  158. Spin-polarized magnetic tunnelling magnetoresistive effects in various junctions Peer-reviewed

    T Miyazaki, N Tezuka, S Kumagai, Y Ando, H Kubota, J Murai, T Watabe, M Yokota

    JOURNAL OF PHYSICS D-APPLIED PHYSICS　31　(6)　630-636　1998/03

    DOI： 10.1088/0022-3727/31/6/009 　

    ISSN： 0022-3727

  159. Barrier height dependence of MR ratio in Fe/Al-oxide/Fe junctions Peer-reviewed

    N Tezuka, T Miyazaki

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　177　1283-1284　1998/01

    DOI： 10.1016/S0304-8853(97)00964-5 　

    ISSN： 0304-8853

  160. Temperature and Applied Voltage Dependence of Magnetoreisitance Ratio in Fe/Al oxide/Fe Junctions Peer-reviewed

    Nobuki Tezuka, Terunobu Miyazaki

    Japanese Journal of Applied Physics　37　L218-L220　1998

    DOI： 10.1143/JJAP.37.L218 　

  161. ウェッジ状のAl－O絶縁層を有する強磁性トンネル接合の磁気抵抗効果 Peer-reviewed

    横田匡史, 安藤康夫, 手束展規, 宮崎照宣

    日本応用磁気学会誌　22　(4)　569-572　1998

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.22.569 　

    ISSN： 0285-0192

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    Ferromagnetic tunneling junctions of Ni80Fe20 (Py)/Co/Al oxide/Co with wedge-shaped insulators were fabricated. Al oxide films were formed by natural oxidization with various conditions and were checked by FT-IR spectroscopy. The peak intensity and the position depending on the Al thickness were explained by using the 1-D Einstein model. When the oxidization time was less than 50 h, tunneling magnetoresistance (TMR) was observed at about 13 Å of the Al thickness. When the oxidization time became more than 50 h, the thickness shifted to less than 10 Å. The reason for this was considered that Co oxide was formed on the surface of the bottom electrode and became a tunneling barrier with increasing oxidization time. On the other hand, the TMR decreased rapidly with increasing Al thickness. To determine the reason for this, AFM images of the Py/Co/Al surface with various oxidization times were measured. The surface roughness of the Al increased with increasing oxidization time, corresponding to the TMR results.

  162. 非弾性電子トンネル分光法（IETS）を用いた強磁性体/絶縁体界面の解析 Peer-reviewed

    村井純一郎, 安藤康夫, 手束展規, 宮崎照宣

    日本応用磁気学会誌　22　(4)　573-576　1998

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.22.573 　

    ISSN： 0285-0192

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    Inelastic electron-tunneling spectroscopy (IETS) has been used to investigate the vibrational spectrum in Al/Al2O3/CO/AI tunneling junctions with various Co thicknesses (d Co). A zero-bias anomaly was observed in the conductance curve of the junction with dCo of 2Å, and decreased with increasing dCo. The IET spectra of these junctions showed strong negative peaks at 4 mV, corresponding to the zero-bias anomaly, while phonon spectra were observed for the junction with dCo ≥ 10Å. The peak position was different from that of Al/Al2O3/Al. After annealing of the junction with dCo of 2Å at 250°C for one hour, the zero-bias anomaly decreased and the phonon spectrum appeared.

  163. NiFe/Co/Al2O3/Co/NiFe/FeMn接合のトンネル磁気抵抗効果 Peer-reviewed

    熊谷静似, 手束展規, 宮崎照宣

    日本応用磁気学会誌　22　(4)　561-564　1998

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.22.561 　

    ISSN： 0285-0192

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    Spin-valve-type ferromagnetic tunneling junctions using contact metal masks were fabricated, and the annealing effect and temperature dependence of the tunneling magnetoresistance (TMR) ratio and saturated resistance (Rs) were investigated. As-prepared NiFe/Co/Al2O3/Co/NiFe/FeMn junctions showed a spin-valve-like MR curve at room temperature. The effect of field annealing was investigated for two reasons: to increase the TMR ratio and: to create an orthogonal magnetic orientation in each of the two magnetic layers. The temperature dependence of the TMR ratio and Rs is affected by the annealing. For the annealed junction, the TMR ratio decreases slightly with increasing temperature and decreases rapidly around 418 K, because of the disappearance of the exchange bias in the FeMn layer.

  164. Spin-polarized tunneling magnetoresistive effect in ferromagnet/insulator/ferromagnet junctions Peer-reviewed

    T Miyazaki, N Tezuka, S Kumagai

    PHYSICA B　237　256-260　1997/07

    DOI： 10.1016/S0921-4526(97)00152-X 　

    ISSN： 0921-4526

  165. 強磁性トンネル接合における絶縁障壁と磁気抵抗 Peer-reviewed

    手束展規, 安藤康夫, 宮崎照宣, H.G. Tompkins, S. Tehrani, H. Goronkin

    日本応用磁気学会誌　21　(4)　493-496　1997

    Publisher: The Magnetics Society of Japan

    DOI： 10.3379/jmsjmag.21.493 　

    ISSN： 0285-0192

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    The dependence of the tunneling magnetoresistive effect on the barrier height was investigated. The magnitude of the barrier height increased with increasing aluminum oxidation temperature and time from 0.3 to 2.3 eV in Fe/Al oxide/Fe junctions. However, those values are smaller than those reported for an Al2O3 barrier. A possible reason for this is that the barrier is not pure Al2O3, but AIOx, or another oxide created by interface mixing between Fe and Al oxide. On the other hand, the magnetoresistance ratio in these junctions varied up to 18% at room temperature and up to 18% at 4.2 K. The dependence of the magnetoresistance ratio at 4.2 K on the barrier height is roughly the same as predicted by Slonczewski's theory. This result shows that the effective spin polarization of ferromagnetic electrodes changes according to the barrier height.

  166. Temperature Dependence of the Spin Tunneling Magnetoresistive Effects on NiFe/Co/Al2O3/Co/NiFe/FeMn Junctions Peer-reviewed

    Seiji Kumagai, Nobuki Tezuka, Terunobu Miyazaki

    Japanese Journal of Applied Physics　36　L1498-L1500　1997

    DOI： 10.1143/JJAP.36.L1498 　

  167. Magnetic tunneling effect in Fe/Al2O3/Ni1-xFex junctions Peer-reviewed

    N Tezuka, T Miyazaki

    JOURNAL OF APPLIED PHYSICS　79　(8)　6262-6264　1996/04

    DOI： 10.1063/1.362028 　

    ISSN： 0021-8979

  168. Spin polarized tunneling in ferromagnet insulator ferromagnet junctions Peer-reviewed

    T Miyazaki, N Tezuka

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS　151　(3)　403-410　1995/12

    DOI： 10.1016/0304-8853(95)00563-3 　

    ISSN： 0304-8853

  169. Giant magnetic tunneling effect in Fe/Al2O3/Fe junction Peer-reviewed

    T. Miyazaki, N. Tezuka

    Journal of Magnetism and Magnetic Materials　139　L231-L234　1995

    DOI： 10.1016/0304-8853(95)90001-2 　

  170. 強磁性/Al2O3/強磁性接合の磁気トンネリング効果 Peer-reviewed

    手束展規, 安藤康夫, 宮崎照宣

    日本応用磁気学会誌　19　369-372　1995

    DOI： 10.3379/jmsjmag.19.369 　

  171. Fe，Ni，Co金属の結晶粒径と保磁力 Peer-reviewed

    佐藤文隆, 手束展規, 桜井伴明, 宮崎照宣

    日本応用磁気学会誌　17　886-891　1993

    DOI： 10.3379/jmsjmag.17.886 　

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Research Projects 3

  1. 高性能永久磁石に関する研究 Competitive

    2000/09 - Present

  2. 高周波磁性材料の開発 Competitive

    2000/09 - Present

  3. スピントランスポートデバイスに関する研究 Competitive

    System: The Other Research Programs

    1994/04 - Present

Social Activities 3

  1. イノベーションジャパン

    2004/09/28 - 2004/09/30

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    最新の研究成果を一般に広く伝え，専門外の人たちにも研究成果を共通の知識としてもらうことに協力

  2. リフレッシュ理科教室

    2001/08/06 - 2001/08/07

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    小・中学生，ならびに，先生に理科の面白さを知ってもらい，現場の先生方に基礎から最新の科学技術までを知る機会を提供

  3. 東北大学サイエンスカフェ

    2007/07/30 -

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    一般市民と研究者が，コーヒーカップを片手にサイエンスについて気軽に話し合い，サイエンスの楽しさと社会貢献の姿を知ってもらう場に協力．

Other 3

  1. 高スピン分極材料を用いた高出力磁気利用センサの開発

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    高スピン分極材料を開発し，磁気利用センサの高性能化を試みる

  2. 反平行結合膜を用いたナノサイズCPP-GMR素子の高再生出力に関する研究

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    反平行結合膜をフリー層に用いた，CPP-GMR素子の再生出力増大に関する研究．

  3. 低磁界・低電力駆動サブミクロン磁性素子の開発

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    サブミクロン磁性素子の低磁界磁化反転に関する研究