Super-spin glass with hierarchical structure aimed for a brain-type memory

2012 Fiscal Year Final Research Report

• Project/Area Number: 23655198
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Inorganic industrial materials
• Research Institution: Kyoto University
• Principal Investigator: TANAKA Katsuhisa 京都大学, 大学院・工学研究科, 教授 (80188292)
• Project Period (FY): 2011 – 2012
• Keywords: スーパースピングラス / スピングラス / 磁性体 / 酸化物 / 階層構造 / 超微粒子 / アモルファス / 薄膜 / ファラデー効果

Research Abstract

Fundamentals of magnetism have been clarified for super-spin glass with hierarchical structure and amorphous oxide magnets which are prototype of random magnetic systems. For the former, an assemblage state of mesoporous silica microparticles with maghemite nanocrystals precipitated in the mesopores has been fabricated. The Faraday effect measurements reveal that the material show superparamagnetism at room temperature. As for the amorphous oxide magnets, oxide glasses containing both iron and rare-earth elements exhibit spin glass or super-spin glass transition, while amorphous EuZrO_3thin film shows re-entrant spin glass transition accompanied by ferromagnetic transition. The mechanism of these magnetic phase transitions have been elucidated.

Research Products

• [Journal Article] Magneto-optical properties of Eu^<2+>-containing aluminoborosilicate glasses with ferromagnetic interactions (2013)
  • Author(s): H. Akamatsu, K. Fujita, Y. Nakatsuka, S. Murai, and K. Tanaka
  • Journal Title: Opt. Mater. Volume: (印刷中)
  • Peer Reviewed
• [Journal Article] Effective optical Faraday rotations of semiconductor EuS nanocrystals with paramagnetic transition-metal ions (2013)
  • Author(s): Y. Hasegawa, M. Maeda, T. Nakanishi, Y. Doi, Y. Hinatsu, K. Fujita, K. Tanaka, H. Koizumi, and K. Fushimi
  • Journal Title: J. Am. Chem. Soc. Volume: 135 Pages: 2659-2666
  • DOI: DOI: 10.1021/ja3106253
  • Peer Reviewed
• [Journal Article] Magnetic and magneto-optical quenching in (Mn^<2+>, Sr^<2+>) metaphosphate glasses (2013)
  • Author(s): A.Winterstein, H. Akamatsu, D. Moncke1, K. Tanaka, M. A. Schmidt, L. Wondraczek
  • Journal Title: Opt. Mater. Express Volume: 3 Pages: 184-193
  • URL: http://dx.doi.org/10.1364/OME.3.000184
  • Peer Reviewed
• [Journal Article] Plasmonically enhanced Faraday effect in metallic and ferrimagnetic nanoparticle composites precipitated inside glass (2012)
  • Author(s): S. Nakashima, K. Sugioka, K. Tanaka, M. Shimizu, Y. Shimotsuma, K. Miura, K. Midorikawa, and K. Mukai
  • Journal Title: Opt. Express Volume: 20 Pages: 28191-28199
  • DOI: DOI:10.1364/OE.20.028191
  • Peer Reviewed
• [Journal Article] (2012)
  • Author(s): S. Murai, S. Yao, T. Nakamura, T. Kawamoto, K. Fujita, K. Yano, and K. Tanaka
  • Journal Title: Appl. Phys. Lett. Volume: 101 Pages: 151121-1-4
  • URL: http://dx.doi.org/10.1063/1.4757608
  • Peer Reviewed
• [Journal Article] Ferromagnetic properties with reentrant spin-glass behavior in amorphous EuZrO_3 thin film (2011)
  • Author(s): Y. Zong, K. Fujita, H. Akamatsu, S. Murai, and K. Tanaka
  • Journal Title: Phys. Stat. Sol. C Volume: 8 Pages: 3051-3054
  • DOI: DOI:10.1002/pssc.201000703
  • Peer Reviewed
• [Journal Article] Magnetic properties of oxide glasses containing iron and rare-earth ions (2011)
  • Author(s): H. Akamatsu, J. Kawabata, K. Fujita, S. Murai, and K. Tanaka
  • Journal Title: Phys. Rev. B Volume: 84 Pages: 144408-1-8
  • DOI: DOI:10.1103/PhysRevB.84.144408
  • Peer Reviewed
• [Presentation] 金属ナノ粒子を堆積させた酸化鉄薄膜におけるファラデー効果の増強 (2013)
  • Author(s): 荒谷誠, 村井俊介, 藤田晃司, 田中勝久
  • Organizer: 日本セラミックス協会
  • Place of Presentation: 東京工業大学
  • Year and Date: 2013-03-17
• [Presentation] ガラスの磁気的性質-基礎と応用- (2011)
  • Author(s): 田中勝久
  • Organizer: ガラス科学技術研究会
  • Place of Presentation: ニューガラスフォーラム, 招待講演
  • Year and Date: 2011-09-29