Design of Spin Transport Properties in Fullerene-Transition Metal Hybrid Materials

2009 Fiscal Year Final Research Report

• Project/Area Number: 19360290
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Physical properties of metals
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: SAKAI Seiji Japan Atomic Energy Agency, 先端基礎研究センター, 研究副主幹 (10354929)
• Co-Investigator(Kenkyū-buntansha): MITANI Seiji 物質材料研究機構, 磁性材料センター, グループリーダー (20250813) ; BABA Yuji 日本原子力研究開発機構, 量子ビーム応用部門, グループリーダー (90360403) ; AVRAMOV Pavel Kirensky Institute of Physics, 教授 (00414582) ; MATSUMOTO Yoshihiro 日本原子力研究開発機構, 先端基礎研究センター, 研究員 (80455287) ; ENTANI Shiro 日本原子力研究開発機構, 先端基礎研究センター, 博士研究員 (40549664)
• Project Period (FY): 2007 – 2009
• Keywords: ナノ物性 / フラーレン / 遷移金属 / ナノ粒子 / 磁気抵抗 / スピントロニクス

Research Abstract

Systematic studies were conducted on the giant TMR effect found in the fullerene(C_<60>)-cobalt(Co) granular thin films, which are composed of a C_<60>-Co compound matrix and Co nanoparticles precipitated therein. It was revealed that the C_<60>-Co films show TMR ratios as high as several 100%-1000% reflecting the dispersion state of Co nanoparticles which can be control by the sample composition. Synchrotron X-ray absorption and magnetic circular dichroism studies clarified that there exist localized d-spins in the C_<60>-Co compound matrix, and the localized spins have a predominant effect on the temperature dependence of the TMR magnitude. It was clarified from the analysis of the electrical and TMR properties of the devices with a nano-layered structure that the giant TMR effect at low temperatures is due to higher-order cotunnleing process, which is related to the granular structure of the films, and, more importantly, due to nearly-complete spin polarization (higher than 80% at zero temperature and bias) of tunneling electrons generated at the interface of Co nanoparticle and the C_<60>-Co compound. The nearly-complete spin polarization of tunneling electron is indicated to be a characteristic nature of the present hybrid system realized under the condition of well defined granular structure and independent of device structure.

Research Products

• [Journal Article] Self-Assembling Hybrid Nanoparticles During Simultaneous Deposition of Co and C60 on Sapphire (2009)
  • Author(s): V. Lavrentiev, V.J. Vacik, H. Naramoto, S. Sakai
  • Journal Title: J. Nanoscience and Nanotechnology 9 Pages: 4305-4310
  • Peer Reviewed
• [Journal Article] X-ray absorption spectroscopy and magnetic circular dichroism in codeposited C60Co films with giant tunnel magnetoresistance (2009)
  • Author(s): Y. Matsumoto, S. Sakai, Y. Takagi, T. Nakagawa, T. Yokoyama, Y. Shimada, S. Mitani, K. Takanashi, H. Naramoto, Y. Maeda
  • Journal Title: Chem. Phys. Lett. 470 Pages: 244-248
  • Peer Reviewed
• [Journal Article] Uniformly dimerized C60 film prepared by deposition under in-situ photoirradiation (2008)
  • Author(s): H. Tanimoto, K. Yamada, H. Mizubayashi, Y. Matsumoto, H. Naramoto, S. Sakai
  • Journal Title: Applied Physics Letters 93 Pages: 151919-1-3
  • Peer Reviewed
• [Journal Article] Theoretical DFT Study of Atomic Structure and Spin States of the Cox(C60)n (x=3-8, n=1, 2) Complex Nanoclusters (2008)
  • Author(s): P. Avramov, S. Sakai, H. Naramoto, K. Narumi, Y. Matsumoto, Y. Maeda
  • Journal Title: J. Phys. Chem. C 112 Pages: 13932-13936
  • Peer Reviewed
• [Journal Article] Giant tunnel magnetoresistance in codeposited fullerene-cobalt films in the low bias-voltage regime (2007)
  • Author(s): S. Sakai, I. Sugai, S. Mitani, K. Takanashi, Y. Matsumoto, H. Naramoto, P.V. Avramov, S. Okayasu, Y. Maeda
  • Journal Title: Appl. Phys. Lett. 91 Pages: 242104-1-3
  • Peer Reviewed
• [Journal Article] Comparative study of structures and electrical properties in cobalt-fullerene mixtures by systematic change of cobalt content (2007)
  • Author(s): S. Sakai, H. Naramoto, P.V. Avramov, T. Yaita, V. Lavrentiev, K. Narumi, Y. Baba, Y. Maeda
  • Journal Title: Thin Solid Films 515 Pages: 7758-7764
  • Peer Reviewed
• [Journal Article] Magnetic and Magnetotransport Properties in Nanogranular Co/C60-Co Film with High Magnetoresitance (2007)
  • Author(s): S. Sakai, K. Yakushiji, S. Mitani, K. Takanashi, H. Naramoto, P.V. Avramov, V. Lavrentiev, K. Narumi, Y. Maeda
  • Journal Title: Mater. Trans. 48 Pages: 754-758
  • Peer Reviewed
• [Journal Article] Quantum Chemical Study of Atomic Structure Evolution of the Cox/C60 (x < 2. 8) Composites (2007)
  • Author(s): P.V. Avramov, H. Naramoto, S. Sakai, K. Narumi, V. Lavrentiev, Y. Maeda
  • Journal Title: J. Phys. Chem. A 111 Pages: 2299-2306
  • Peer Reviewed
• [Presentation] フラーレン-コバルト系薄膜に於ける高スピン偏極トンネル電流 (2010)
  • Author(s): 境誠司, 松本吉弘, 圓谷志郎, 菅井勇, 高梨弘毅, 三谷誠司, 楢本洋, 前田佳均
  • Organizer: 日本金属学会2010年春期大会(第146回)
  • Place of Presentation: つくば
  • Year and Date: 20100328-20100330
• [Presentation] 顕微ラマン分光法によるグラフェン/磁性金属界面の相互作用の評価 (2010)
  • Author(s): 圓谷志郎, 境誠司, 松本吉弘, 楢本洋, 高梨弘毅, 前田佳均
  • Organizer: 日本金属学会2010年春期大会(第146回)
  • Place of Presentation: つくば
  • Year and Date: 20100328-20100330
• [Presentation] 巨大TMR効果に影響を及ぼすC60-Co化合物の電子/スピン状態(II) (2010)
  • Author(s): 松本吉弘, 境誠司, 圓谷志郎, 永松伸一, 北條育子, 藤川高志, 島田敏宏, 楢本洋, 前田佳均, 横山利彦
  • Organizer: 2010年春季第57回応用物理学関係連合講演会
  • Place of Presentation: 平塚
  • Year and Date: 20100317-20100320
• [Presentation] Magnetic properties of C60-Co compound in granular C60-Co films with giant TMR effect (2010)
  • Author(s): Y. Matsumoto, S. Sakai, S. Entani, Y. Takagi, T. Nakagawa, S. Nagamatsu, T. Shimada, H. Naramoto, T. Yokoyama, Y. Maeda
  • Organizer: 11th Joint MMM-Intermag Conreference
  • Place of Presentation: Washington, DC, USA
  • Year and Date: 20100114-20100117
• [Presentation] interface spin-polarization in granular C60-Co films (2009)
  • Author(s): S. Sakai, Y. Matsumoto, S. Entani, I. Sugai, K. Takanashi, Y. Takagi, T. Nakagawa, T. Yokoyama, T. Shimada, H. Naramoto, Y. Maeda
  • Organizer: International IMRWorkshop onGroup IV Spintronics
  • Place of Presentation: Sendai, Miyagi, Japan
  • Year and Date: 20091005-20091006
• [Presentation] グラニュラーC60-Co薄膜の巨大TMR効果と高スピン偏極界面 (2009)
  • Author(s): 境誠司, 松本吉弘, 圓谷志郎, 菅井勇, 三谷誠司, 高梨弘毅, 楢本洋, 前田佳均
  • Organizer: 2009年秋季第70回応用物理学会学術講演会
  • Place of Presentation: 富山
  • Year and Date: 20090908-20090911
• [Presentation] Giant TMR effect and spin states in fullerene-cobalt hybrid films (2009)
  • Author(s): S. Sakai, Y. Masumoto, S. Mitani, K. Takanashi, Y. Takagi, T. Nakagawa, T. Yokoyama, T. Shimada, H. Naramoto, Y. Maeda
  • Organizer: 2nd Topical Meeting on Spins in Organic Semiconductors (SPINOS 2009)
  • Place of Presentation: Salt Lake City, Utah, USA
  • Year and Date: 20090204-20090207
• [Presentation] フラーレン-Coハイブリッド系グラニュラー薄膜の磁気伝導現象と電子・スピン状態 (2009)
  • Author(s): 境誠司
  • Organizer: 日本金属学会分科会シンポジウム「スピントロニクス・ナノ磁性材料の進展と将来展望」
  • Place of Presentation: 仙台
  • Year and Date: 2009-01-06
• [Presentation] Electronic and Spin States of C60-Co Thin Films Studied by XPS and X-ray Magnetic Circular Dichroism (2008)
  • Author(s): Y. Matsumoto, S. Sakai, H. Naramoto, T. Nakagawa, Y. Takagi, T. Yokoyama, T. Shimada, N. Hirao, Y. Baba, Y. Maeda
  • Organizer: Materials Research Society(MRS) 2008 Fall Meeting
  • Place of Presentation: Boston, USA
  • Year and Date: 20081201-20081205
• [Presentation] Giant TMR effect in granular-structured C60-Co hybrid films (2008)
  • Author(s): S. Sakai, Y. Matsumoto, I. Sugai, S. Mitani, K. Takanashi, Y. Takagi, T. Nakagawa, T. Yokoyama, H. Naramoto, Y. Maeda
  • Organizer: Materials Research Society(MRS) 2008 Fall Meeting
  • Place of Presentation: Boston, USA
  • Year and Date: 20081201-20081205
• [Presentation] 巨大トンネル磁気抵抗効果を示すC60-Co共蒸着薄膜の電子・磁気状態 (2008)
  • Author(s): 松本吉弘, 境誠司, 楢本洋, 中川剛志, 高木康多, 横山利彦, 島田敏宏, 三谷誠司, 高梨弘毅、前田佳均
  • Organizer: 第2回分子科学討論会
  • Place of Presentation: 福岡
  • Year and Date: 20080924-20080927
• [Presentation] 巨大トンネル磁気抵抗を示すC60-Co薄膜の磁気伝導特性の系統的評価 (2008)
  • Author(s): 境誠司, 松本吉弘, 菅井勇, 三谷誠司, 高梨弘毅, 楢本洋, 岡安悟, 前田佳均
  • Organizer: 2008年秋季第69回応用物理学会学術講演会
  • Place of Presentation: 愛知
  • Year and Date: 20080902-20080905
• [Presentation] The Electronic Structures of Fullerene - Transition Metal Hybrid Material (2008)
  • Author(s): Y. Matsumoto, S. Sakai, H. Naramoto, N. Hirao, Y. Baba, I. Sugai, K. Takanashi, S. Okayasu, Y. Maeda
  • Organizer: 2008 Materials Research Society (MRS) Spring Meeting
  • Place of Presentation: San Francisco, USA
  • Year and Date: 20080324-20080328
• [Presentation] C60-Co薄膜のトンネル磁気抵抗効果の組成依存性 (2008)
  • Author(s): 境誠司, 菅井勇, 三谷誠司, 松本吉弘, 高梨弘毅, 楢本洋, Pavel Avramov, 岡安悟, 前田佳均
  • Organizer: 日本金属学会2008年春期(第142回)大会
  • Place of Presentation: 東京
  • Year and Date: 2008-03-28
• [Presentation] Large TunnelMagnetoresistance in Co-evaportated C60-Co Thin Films (2007)
  • Author(s): S. Sakai, I. Sugai, S. Mitani, Y. Matsumoto, K. Takanashi, H. Naramoto, P.V. Avramov, S. Okayasu, Y. Maeda
  • Organizer: 2007 Materials Research Society(MRS) Fall Meeting
  • Place of Presentation: Boston, USA
  • Year and Date: 20071126-20071130
• [Presentation] Large Magnetoresistance Effect in C60-Co Nanogranular Thin Films (2007)
  • Author(s): I. Sugai, S. Sakai, S. Mitani, Y. Matsumoto, K. Takanashi, H. Naramoto, P.V. Avramov, S. Okayasu, Y. Maeda
  • Organizer: 52nd Magnetism andMagneticMaterials Conference
  • Place of Presentation: Tampa, USA
  • Year and Date: 20071105-20071109
• [Presentation] フラーレン-コバルト薄膜の磁気抵抗効果と構造 (2007)
  • Author(s): 境誠司, 菅井勇, 三谷誠司, 松本吉弘, 高梨弘毅, 楢本洋, 岡安悟, 前田佳均
  • Organizer: 日本応用磁気学会第31回学術講演会
  • Place of Presentation: 東京
  • Year and Date: 20070911-20070914
• [Remarks]
  • URL: http://asrc.jaea.go.jp/
• [Remarks] フラーレン-コバルト化合物を含むナノグラニュラー薄膜に巨大な磁気抵抗効果を発見-フラーレンのスピントロニクス分野への応用を拓く-,境誠司,日本原子力研究開発機構プレス発表,平成18年9月発表
• [Remarks] フラーレン-コバルト薄膜の巨大な磁気抵抗効果の起源を解明-有機分子のスピンが流れる電子のスピンを偏らせる-,松本吉弘,境誠司,日本原子力研究開発機構プレス発表,平成21年1月発表