Study on spin dependent transport in ferromagnet/semiconductor heterostructures

2008 Fiscal Year Final Research Report

• Project/Area Number: 19560307
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Hokkaido University
• Principal Investigator: UEMURA Tetsuya Hokkaido University, 大学院・情報科学研究科, 准教授 (20344476)
• Project Period (FY): 2007 – 2008
• Keywords: スピンエレクトロニクス

Research Abstract

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。

Research Products

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