Creation of highly efficient spin sources with half-metals

2009 Fiscal Year Self-evaluation Report

• Project Area: Creation and control of spin current
• Project/Area Number: 19048001
• Research Category: Grant-in-Aid for Scientific Research on Priority Areas
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Hokkaido University
• Principal Investigator: YAMAMOTO Masafumi Hokkaido University, 大学院・情報科学研究科, 教授 (10322835)
• Project Period (FY): 2007 – 2010
• Keywords: スピン源 / ハーフメタル / ホイスラー合金 / スピントロニクス / スピン偏極率

Research Abstract

次世代のエレクトロニクス,あるいは,量子情報処理において、固体中の電子の電荷とスピンの自由度を併せて用いるスピントロニクスの研究が盛んである.スピントロニクスにおいて,スピン源は最も基本的な構成要素である.スピン源として理想的と考えられる材料系の一つはハーフメタルである.本研究の大きな目的は高効率スピン源の創出にある.本研究ではオリジナルの技術であるハーフメタル系ホイスラー合金(Co_2YZ)薄膜とMgOバリアを組み合わせた単結晶エピタキシャルヘテロ構造を技術の核として,Co_2YZ物質群を広く探索し、高効率スピン源を創出することを目的とする.

Research Products

• [Journal Article] Interface Structure of Half-Metallic Heusler Alloy Co2MnSi Thin Films Facing an MgO Tunnel Barrier Determined by X-ray Magnetic Circular Dichroism (2010)
  • Author(s): T.Saito, T.Katayama, T.Ishikawa, M.Yamamoto, D.Asakura, T.Koide, M.Miura, M.Shirai
  • Journal Title: Phys.Rev.B vol.81 Pages: 144417
  • Peer Reviewed
• [Journal Article] Effect of defects in Heusler alloy thin films on spin-dependent tunnelling characteristics of Co_2MnSi/MgO/Co_2MnSi and Co_2MnGe/MgO/Co_2MnGe magnetic tunnel junctions (2010)
  • Author(s): M.Yamamoto, T.Ishikawa, T.Taira, G.-f.Li, K.-i.Matsuda, T.Uemura
  • Journal Title: J.Phys.: Condens.Matter vol22 Pages: 164212
  • Peer Reviewed
• [Journal Article] Influence of film composition in Co_2MnSi electrodes on tunnel magnetoresistance characteristics of Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junction (2009)
  • Author(s): T.Ishikawa, H.-x.Liu, T.Taira, K.-i.Matsuda, T.Uemura, M.Yamamoto
  • Journal Title: Appl.Phys.Lett. 95 Pages: 232512
  • Peer Reviewed
• [Journal Article] Half-metallic electronic structure of Co_2MnSi electrodes in fully epitaxial Co_2MnSi/MgO/Co_2MnSi magnetic tunnel junctions investigated by tunneling spectroscopy (2009)
  • Author(s): T.Ishikawa, N.Itabashi, T.Taira, K.-i.Matsuda, T.Uemura, M.Yamamoto
  • Journal Title: J.Appl.Phys. 105(invited) Pages: 07B110
  • 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.-i.Matsuda, T.Uemura, M.Yamamoto
  • Journal Title: Appl.Phys.Lett. vol.94 Pages: 092503
  • Peer Reviewed
• [Presentation] Spin-dependent tunneling in half-metallic Heusler alloy-based magnetic tunnel junctions with a MgO barrier (2009)
  • Author(s): M.Yamamoto, T.Ishikawa, T.Taira, T.Marukame, K.-i.Matsuda, T.Uemura
  • Organizer: Int'l Conf on Magnetism (ICM2009)
  • Place of Presentation: Karlsruhe, Germany(Invited Talk)
  • Year and Date: 20090726-20090731
• [Book] Advances in Solid State Physics, vol.47(R.Haug (Ed.), Highly Spin-Polarized Tunneling in Fully Epitaxial Magnetic Tunnel Junctions with a Co-Based Full-Heusler Alloy Thin Film and a MgO Barrier) (2008)
  • Author(s): M.Yamamoto, T.Marukame, T.Ishikawa, K.-i.Matsuda, T.Uemura
  • Total Pages: 105-116
  • Publisher: Springer
• [Remarks]
  • URL: http://nsed.ist.hokudai.ac.jp/index.html