強磁性体/半導体へテロ構造におけるスピン依存伝導の研究

2008 年度 研究成果報告書

• 研究課題/領域番号: 19560307
• 研究種目: 基盤研究(C)
• 配分区分: 補助金
• 応募区分: 一般
• 研究分野: 電子・電気材料工学
• 研究機関: 北海道大学
• 研究代表者: 植村 哲也 北海道大学, 大学院・情報科学研究科, 准教授 (20344476)
• 研究期間 (年度): 2007 – 2008
• キーワード: スピンエレクトロニクス

研究概要

半導体中の伝導電子のスピンを操作し、これまでにない新しい機能を有する電子/光デバイスの研究が盛んに行われている。その実現の第一歩は、スピン偏極した電子を半導体内に発生させることであり、強磁性電極から半導体にスピン偏極した電子を電気的に注入する方法(スピン注入)が有効である。本研究では、高効率スピン注入の実現に向け、スピン偏極率の高いハーフメタル材料であるCo系ホイスラー合金薄膜を半導体GaAs上に高品質に形成するとともに、ホイスラー合金/GaAsヘテロ接合構造におけるスピン依存伝導特性を明らかにした。このことにより、将来の新しいスピン機能デバイスの創出にむけた基盤技術を確立した。

研究成果

• [雑誌論文] Tunneling anisotropic magnetoresistance in epitaxial CoFe/n-GaAs junctions (2009)
  • 著者名/発表者名: T. Uemura, Y. Imai, M. Harada, K.-i. Matsuda, and M. Yamamoto
  • 雑誌名: Appl Phys. Lett vol.94 ページ: 182502-1-182502-3
  • 査読あり
• [雑誌論文] Transport properties of Nb/PdNi bilayers and Nb/PdNi/Nb Josephson junctions (2009)
  • 著者名/発表者名: K. -i. Matsuda, Y. Akimoto, T. Uemura and M. Yamamoto
  • 雑誌名: J. Physics : Conference Series vol.150 ページ: 0521551-1-0521551-4
  • 査読あり
• [雑誌論文] Spin-dependent tunnelling characteristics of fully epitaxial magnetic tunnel junctions with a Heusler alloy Co_2MnGe thin film and a MgO barrier (2009)
  • 著者名/発表者名: T. Taira, T. Ishikawa, N. Itabashi, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: J. Phys. D. vol.42 ページ: 084015(9)
  • 査読あり
• [雑誌論文] Hard X-ray photoelectron spectroscopy of buried Heusler compounds (2009)
  • 著者名/発表者名: S. Ouardi, B. Balke, A. Gloskovskii, G. H Fecher, C. Felser, G. Schoenhense, T. Ishikawa, T. Uemura, M. Yamamoto, H. Sukegawa, W.-H Wang, K. Inomata, Y. Yamashita, H. Yoshikawa, S. Ueda and K. Kobayashi
  • 雑誌名: J. Phys. D vol.42 ページ: 084010(7)
  • 査読あり
• [雑誌論文] Half-metallic electronic structure of Co_2MnSi electrodes in fully epitaxial Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junctions proved by tunneling spectroscopy (2009)
  • 著者名/発表者名: T. Ishikawa, N. Itabashi, T. Taira, K.-. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.105 ページ: 07B110-1-07B110-6
  • 査読あり
• [雑誌論文] Critical role of interface states for spin-dependent tunneling in half-metallic Co_2MnSi-based magnetic tunnel junctions investigated by tunneling spectroscopy (2009)
  • 著者名/発表者名: T. Ishikawa, N. Itabashi, T. Taira, K.-. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: Appl. Phys. Lett vol.94 ページ: 092503-1-092503-3
  • 査読あり
• [雑誌論文] Influence of annealing on spin-dependent tunneling characteristics of fully epitaxial Co_2MnGe/MgO/Co_<50>Fe_<50> magnetic tunnel junctions (2009)
  • 著者名/発表者名: T. Taira, T. Ishikawa, N. Itabashi, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: Appl. Phys. Lett vol.94 ページ: 072510-1-072510-3
  • 査読あり
• [雑誌論文] Three-valued Magnetic Tunnel Junction for Non-volatile Ternary Content Addressable Memory Application (2008)
  • 著者名/発表者名: T. Uemura and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.104 ページ: 123911-1-123911-5
  • 査読あり
• [雑誌論文] Fabrication and Characterization of Fully Epitaxial Magnetic Tunnel Junction Field Sensors using a Co_2MnSi Thin Film (2008)
  • 著者名/発表者名: M. Masuda, T. Uemura, K.-i. Matsuda and M. Yamamoto
  • 雑誌名: IEEE Transactions on Magnetics vol.44 ページ: 3996-3998
  • 査読あり
• [雑誌論文] Epitaxial growth and characterization of Co_2MnSi thin films on GaAs with MgO interlayer (2008)
  • 著者名/発表者名: T. Uemura, Y. Imai, S. Kawagishi, K.-i. Matsuda, and M. Yamamoto
  • 雑誌名: Physica E: Low-dimensional Systems and Nanostructures vol.40 ページ: 2025-2027
  • 査読あり
• [雑誌論文] Fabrication of fully epitaxial Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junctions (2008)
  • 著者名/発表者名: T. Ishikawa, S. Hakamata, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.103 ページ: 07A919-1-07A919-3
  • 査読あり
• [雑誌論文] Electronic and magnetic properties of Heusler alloy Co_2MnSi epitaxial ultrathin films facing a MgO barrier studied by X-ray magnetic circular dichroism (2008)
  • 著者名/発表者名: T. Saito, T. Katayama, A. Emura, N. Sumida, N. Matsuoka, T. Ishikawa, T Uemura, M. Yamamoto, D. Asakura, and T. Koide
  • 雑誌名: J. Appl. Phys vol.103 ページ: 07D712-1-07D712-3
  • 査読あり
• [雑誌論文] Magnetic and transport properties of superconductor/ferromagnetic bilayer microbridges (2008)
  • 著者名/発表者名: K.-i. Matsuda, Y. Akimoto, T. Uemura, and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.103 ページ: 07C711-1-07C711-3
  • 査読あり
• [雑誌論文] Structural, magnetic and electrical properties of Co2MnSi/MgO/n-GaAs tunnel junction (2008)
  • 著者名/発表者名: S. Kawagishi, T. Uemura, Y. Imai, K.-i. Matsuda, and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.103 ページ: 07A703-1-07A703-3
  • 査読あり
• [雑誌論文] Structural and magnetic properties of Co_2Cr_<0.6>Fe_<0.4>Al thin films epitaxially grown on GaAs substrate with MgO interlayer (2007)
  • 著者名/発表者名: T. Uemura, T. Yano, K.-i. Matsuda, and M. Yamamoto
  • 雑誌名: Thin Solid Films vol.515 ページ: 8013-8016
  • 査読あり
• [雑誌論文] Fabrication of Epitaxial Magnetic Tunnel Junctions with a Co_2Cr^<0.6>Fe^<0.4>Al Thin Film and Their Tunnel Magnetoresistance Characteristics (2007)
  • 著者名/発表者名: T. Marukame, T. Ishikawa, S. Hakamata, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 雑誌名: J. Magn. Soc. Jpn vol.31 ページ: 344-350
  • 査読あり
• [雑誌論文] Four-state Magnetoresistance in Epitaxial CoFe-based Magnetic Tunnel Junction (2007)
  • 著者名/発表者名: T. Uemura, T. Marukame, K.-i. Matsuda, and M.Yamamoto
  • 雑誌名: IEEE Trans. on Magn vol.43 ページ: 2791-2793
  • 査読あり
• [雑誌論文] Magnetic and Transport Properties of Nb/PdNi Bilayers (2007)
  • 著者名/発表者名: K.-i. Matsuda, H. Niwa, Y. Akimoto, T. Uemura, and M. Yamamoto
  • 雑誌名: IEEE Trans. on Appl. Supercond vol.17 ページ: 3529-3532
  • 査読あり
• [雑誌論文] Improved tunnel magnetoresistance characteristics of magnetic tunnel junctions with a Heusler alloy thin film of Co2MnGe and a MgO tunnel barrier (2007)
  • 著者名/発表者名: S. Hakamata, T. Ishikawa, T. Marukame, K.-i. Matsuda, T. Uemura, M. Arita, and M. Yamamoto
  • 雑誌名: J. Appl. Phys vol.101 ページ: 09J513-1-09J513-3
  • 査読あり
• [雑誌論文] Tunneling Magnetoreistance Simulation Used to Detect Domain-wall Structures and Their Motion in a Ferromagnetic Wire
  • 著者名/発表者名: K. Sawada, T. Uemura, M. Masuda, K.-i. Matsuda, and M. Yamamoto
  • 雑誌名: IEEE Trans. on Magnetics (in press)
  • 査読あり
• [学会発表] Tunneling Anisotropic Magneto-resistance in an Epitaxial CoFe/n-GaAs Junction (2009)
  • 著者名/発表者名: T. Uemura, Y. Imai, M. Harada, K.-i. Matsuda, and M. Yamamoto
  • 学会等名: IEEE International Magnetics Conference 2009
  • 発表場所: Sacramento, CA, USA(BQ-13)
  • 年月日: 20090504-08
• [学会発表] Simulation of tunneling magnetoresistance used to detect domain-wall structure and motion in a ferromagnetic wire (2009)
  • 著者名/発表者名: K. Sawada, T. Uemura, M. Masuda, K.-i.Matsuda, and M. Yamamoto
  • 学会等名: IEEE International Magnetics Conference 2009
  • 発表場所: Sacramento, CA, USA(BD-07)
  • 年月日: 20090504-08
• [学会発表] Tunneling spectroscopy of fully epitaxial Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junctions (2008)
  • 著者名/発表者名: T. Ishikawa, N. Itabashi, T. Taira, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 2008 Material Research Society (MRS) Fall Meeting
  • 発表場所: Boston, MA, USA(L5.1)
  • 年月日: 20081201-05
• [学会発表] Tunneling conductance characteristics for Co_2Cr_<0.6>_Fe_<0.4>Al/MgO/Co_2Cr_<0.6>Fe_<0.4>Al magnetic tunnel junctions (2008)
  • 著者名/発表者名: N. Itabashi, T. Ishikawa, K. Yonemura, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 2008 Material Research Society (MRS) Fall Meeting
  • 発表場所: Boston, MA, USA(L2.10)
  • 年月日: 20081201-05
• [学会発表] Spin-polarized tunneling in fully epitaxial magnetic tunnel junctions with Heusler alloy thin films and a MgO barrier (2008)
  • 著者名/発表者名: M. Yamamoto, T. Ishikawa, K.-i. Matsuda, and T. Uemura
  • 学会等名: 2008 Material Research Society (MRS) Fall Meeting
  • 発表場所: Boston, MA, USA(L2.6)[Invited Talk]
  • 年月日: 20081201-05
• [学会発表] Spin-dependent electronic structures of Co_2Cr_<0.6>Fe_<0.4>Al electrodes investigated through tunneling spectroscopy (2008)
  • 著者名/発表者名: N. Itabashi, T. Ishikawa, K. Yonemura, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 53^<rd> Magnetism and Magnetic Materials Conference
  • 発表場所: Austin, TX, USA(GT-03)
  • 年月日: 20081110-15
• [学会発表] Tunneling spectroscopy of Co_2Cr_<0.6>Fe_<0.4>Al/MgO/CoFe magnetic tunnel junctions (2008)
  • 著者名/発表者名: K. Yonemura, T. Ishikawa, N. Itabashi, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 53^<rd> Magnetism and Magnetic Materials Conference
  • 発表場所: Austin, TX, USA(ED-07)
  • 年月日: 20081110-15
• [学会発表] Spin-dependent tunneling characteristics of Co_2MnGe/MgO/CoFe tunnel junctions (2008)
  • 著者名/発表者名: T. Taira, T. Ishikawa, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 学会等名: 53rd Magnetism and Magnetic Materials Conference
  • 発表場所: Austin, TX, USA(DD-02)
  • 年月日: 20081110-15
• [学会発表] Half-metallic electronic structure of Co_2MnSi electrodes proved by tunneling spectroscopy (2008)
  • 著者名/発表者名: T. Ishikawa, N. Itabashi, T. Taira, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 53^<rd> Magnetism and Magnetic Materials Conference
  • 発表場所: Austin, TX, USA(DD-07)[Invited Talk]
  • 年月日: 20081110-15
• [学会発表] Fabrication of fully epitaxial magnetic tunnel junctions with half-metallic Heusler alloy thin films and a MgO tunnel barrier (2008)
  • 著者名/発表者名: M. Yamamoto, T. Uemura, and K.i. Matusda
  • 学会等名: The 10^<th> Int'l Joint Symposium between Hokkaido University and Chungnam National University, Sapporo
  • 発表場所: Hokkaido University and Chungnam National University[Invited Talk]
  • 年月日: 20081022-24
• [学会発表] Sp-in-dependent tunneling spectroscopy of fully epitaxial magnetic tunnel junctions with Heusler alloy Co_2Cr_<0:6>Fe_<0:4>Al electrodes and a MgO barrier (2008)
  • 著者名/発表者名: N. Itabashi, T. Ishikawa, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 学会等名: 25^<th> Int'l Conf. on Low Temp. Physics
  • 発表場所: Amsterdam, The Netherlands(PD-Mo244)
  • 年月日: 20080806-13
• [学会発表] Transport Properties of Nb/PdNi bilayers and Nb/PdNi/Nb Josephson junctions (2008)
  • 著者名/発表者名: K.-i. Matsuda, Y. Akimoto, T. Uemura, and M. Yamamoto
  • 学会等名: 25^<th> Int'l Conf. on Low Temp. Physics
  • 発表場所: Amsterdam, The Netherlands(PB-Th118)
  • 年月日: 20080806-13
• [学会発表] Spin-dependent tunneling conductance in fully epitaxial Co_2MnSi/MgO/Co_2MnsI tunnel junctions (2008)
  • 著者名/発表者名: T. Ishikawa, N. Itabashi, K. Matsuda, T. Uemura, and M. Yamamoto
  • 学会等名: IEEE Int'l Magnetics Conf. Europe 2008
  • 発表場所: Madrid, Spain(AC-07)
  • 年月日: 20080504-08
• [学会発表] Fabrication and characterization of magnetic tunnel junction field sensors with a Co_2MnSi thin film (2008)
  • 著者名/発表者名: M. Masuda, T. Uemura, K.-i. Matsuda and M. Yamamoto
  • 学会等名: IEEE Int'l Magnetics Conf
  • 発表場所: Europe 2008(BD-04)
  • 年月日: 20080504-08
• [学会発表] Heusler alloy-based fully epitaxial magnetic tunnel junctions with a MgO barrier (2008)
  • 著者名/発表者名: M. Yamamoto, T. Uemura, and K.-i. Matsuda
  • 学会等名: 2008 RCIQE Int'l Seminar on "Advanced Semiconductor Materials and Devices"
  • 発表場所: Sapporo, Japan[Invited Talk]
  • 年月日: 20080303-04
• [学会発表] Tunnel magnetoresistance characteristics of post-deposition-annealed Co_2MnGe/MgO/CoFe tunnel junctions (2008)
  • 著者名/発表者名: T. Taira, T. Ishikawa, K.-i. Matsuda, T. Uemura and M. Yamamoto
  • 学会等名: 2008 Material Research Society (MRS) Fall Meeting
  • 発表場所: Boston, MA, USA(L2.1)
  • 年月日: 2008-12-02
• [学会発表] Highly spin-polarized tunneling in Heusler alloy-based fully epitaxial magnetic tunnel junctions with a MgO tunnel barrier (2007)
  • 著者名/発表者名: M. Yamamoto, T. Marukame, T. Ishikawa, K. Matsuda, and T. Uemura
  • 学会等名: 52^<nd> Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA(DB-01)[Invited Talk]
  • 年月日: 20071105-09
• [学会発表] Spin-dependent tunneling in fully epitaxial Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junctions (2007)
  • 著者名/発表者名: T. Ishikawa, S. Hakamata, K.-i. Matsuda, T. Uemura, and M. Yamamoto
  • 学会等名: 52^nd Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA(AB-07)
  • 年月日: 20071105-09
• [学会発表] Electronic and magnetic properties of Heusler alloy Co_2MnSi epitaxial ultrathin films facing a MgO barrier investigated by X-ray magnetic circular dichroism (2007)
  • 著者名/発表者名: T. Saito, T. Katayama, A. Emura, N. Sumida, N. Matsuoka, T. Ishikawa, T. Uemura, M. Yamamoto, D. Asakura, and T. Koide
  • 学会等名: 52^nd Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA(BQ-06)
  • 年月日: 20071105-09
• [学会発表] Electrical characterization of epitaxial Co_2MnSi/MgO/n-GaAs tunnel junctions (2007)
  • 著者名/発表者名: S. Kawagishi, T. Uemura, Y. Imai, K.-i. Matsuda, and M. Yamamoto
  • 学会等名: 52^<nd> Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA
  • 年月日: 20071105-09
• [学会発表] Magnetic and transport properties of superconductor/ferromagnet bilayer microbridges (2007)
  • 著者名/発表者名: K.-i. Matsuda, Y. Akimoto, T. Uemura, and M. Yamamoto
  • 学会等名: 52^nd Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA
  • 年月日: 20071105-09
• [学会発表] Epitaxial growth and characterization of Co_2MnSi thin films on GaAs with MgO interlayer (2007)
  • 著者名/発表者名: T. Uemura, T. Yano, Y. Imai, K. Matsuda, and M. Yamamoto
  • 学会等名: The 13^<th> Int'l Conf. on Modulated Semiconductor Structures
  • 発表場所: Genova, Italy
  • 年月日: 20070715-20
• [学会発表] Four-state Magnetic Random Access Memory and Ternary Content Addressable Memory using CoFe-based Magnetic Tunnel Junctions (2007)
  • 著者名/発表者名: T. Uemura, T. Marukame, K.-i. Matsuda, and M. Yamamoto
  • 学会等名: 37^<th> Int'l Symposium om Multiple-Valued Logic
  • 発表場所: Oslo, Norway
  • 年月日: 20070513-16
• [学会発表] Oscillations in tunneling resistance as a function of MgO barrier thickness in fully epitaxial magnetic tunnel junctions of Co_2Cr^<0.6>Fe^<0.4>Al/MgO/Co^<50>Fe^<50> (2007)
  • 著者名/発表者名: M. Yamamoto, T. Marukame, T. Ishikawa, K. Matsuda, and T. Uemura
  • 学会等名: 52^nd Magnetism and Magnetic Materials Conference
  • 発表場所: Tampa, Florida, USA(AB-11)
  • 年月日: 2007-11-06
• [図書] Springer Berlin/Heidelberg, Advances in Solid State Physics 47, R. Haug (Ed.) (2008)
  • 著者名/発表者名: M. Yamamoto, T. Marukame, T. Ishikawa, K.-i. Matsuda, and T. Uemura
  • 総ページ数: 105-116
  • 出版者: Highly Spin-Polarized Tunneling in Fully Epitaxial Magnetic Tunnel Junctions with a Co-Based Full-Heusler Alloy Thin Film and a MgO Barrier