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2005 Fiscal Year Final Research Report Summary

Development of molecular conducting magnets oriented to π-d interaction control

Research Project

Project/Area Number 14540530
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 機能・物性・材料
Research InstitutionTokyo Institute of Technology

Principal Investigator

MIYAZAKI Akira  Tokyo Institute of Technology, Department of Chemistry, Research Associate, 大学院・理工学研究科, 助手 (40251607)

Co-Investigator(Kenkyū-buntansha) ENOKI Toshiaki  Tokyo Institute of Technology, Department of Chemistry, Professor, 大学院・理工学研究科, 教授 (10113424)
Project Period (FY) 2002 – 2005
KeywordsMolecular conductors / Molecular magnets / π-d interaction / Magnetotransport properties / Antiferromagnets / Weak ferromagnets / Magnetism under pressure / Canted-spin structure
Research Abstract

1. The electrical resistivities and magnetoresistances (MR) of a radical ion salt (EDO-TTFBr_2)_2MCl_4 (M=Fe,Ga) are investigated under pressures. The resistivity of the FeCl4 salt shows two anomalies due to the successive transitions of the π-electron layer, and another anomaly coming from the long-range magnetic ordering of the FeCl_4 layer. For the GaCl_4 salt negative MR is observed in the low-field region, suggesting a decrease of the SDW gap by applying the magnetic field. The MR of the FeCl_4 salt shows two abrupt increases, which proves the presence of field-induced successive transitions in the composite π-d spin system. The field dependence of the MR of this salt can be qualitatively explained based on the frustrated magnetic structure of π- and d-electron spins interacting with each other.
2. The magnetic properties of weak ferromagnets (BDH-TTP)[M(isoq)_2(NCS)_4] (M = Cr, Fe ; isoq = isoquinoline) is investigated. These salts form two-dimensional magnetic sheets, where ferri … More magnetic chains of donor cation radical and anion are antiferromagnetically connected by S…S contacts. Under ambient pressure, both the Cr and Fe salts undergo a weak ferromagnetic transition at T_N = 7.6 K. The application of pressure elevates the transition temperatures up to 16.6 K and 11.6 K at 9 kbar for M = Cr and Fe, respectively. The pressure dependence of the remanent magnetization indicates that the spin canting angle of the Cr salt is reduced due to the increase of antiferromagnetic interaction by applied pressure, in contrast to the Fe salt where the Fe spins are more canted due to the increase of the Dzyaloshinsky-Moriya interaction. The mean-field analysis reveals that the intermolecular exchange interaction increases as the pressure increases, among which the inter-chain anion-anion interaction has the highest pressure sensitivity. This result is consistent with the temperature dependence of the crystal structure showing the thermal contraction in the distances of inter-chain anion-anion S…S contacts is the most remarkable in intra-chain S…S contacts. Less

  • Research Products

    (14 results)

All 2006 2005 2004 2003

All Journal Article (13 results) Book (1 results)

  • [Journal Article] Pressure Effect on Bulk Weak-Ferromagnets : (BDH-TTP)[M(isoq)_2(NCS)_4](M=Cr^III,Fe^III; isoq=isoquinoline)2006

    • Author(s)
      S.Kudo et al.
    • Journal Title

      Inorg. Chem. 45(9)

      Pages: 3718-3725

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Physical properties of π-d interaction-based molecular conducting magnet(EDO-TTFBr_2)_2FeCl_4 under pressure2006

    • Author(s)
      A.Miyazaki et al.
    • Journal Title

      J. Low Temp Phys. 142(In press)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Pressure effect on the electrical conductivity and superconductivity of β-(BDA-TTP)_2I_32006

    • Author(s)
      J.Yamada et al.
    • Journal Title

      Chem. Commun.

      Pages: 1331-1333

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Pressure Effect on Bulk Weak-Ferromagnets : (BDH-TTP)[M(isoq)_2(NCS)_4] (M=CR^<III>,Fe^<III>;isoq=isoquinoline)2006

    • Author(s)
      S.Kudo, A.Miyazaki, T.Enoki, S.Golhen, L.Ouahab, T.Toita, J.Yamada
    • Journal Title

      Inorg.Chem 45

      Pages: 3718-3725

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Physical properties of π-d interaction-based molecular conducting magnet (EDO-TTFBr_2)_2FeCl_4 under pressure2006

    • Author(s)
      A.Miyazaki, M.Aimatsu, T.Enoki, R.Watanabe, E.Ogura, Y.Kuwatani, M.Iyoda
    • Journal Title

      J.Low Temp Phys. 142(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Pressure effect on the electrical conductivity and superconductivity of β-(BDA-TTP)_2I_32006

    • Author(s)
      J.Yamada, K.Fujimoto, H.Akutsu, S.-I.Nakatsuji, A.Miyazaki, M.Aimatsu, S.Kudo, T.Enoki, K.Kikuchi
    • Journal Title

      Chem.Commun.

      Pages: 1331-1333

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] π-d Interaction-based molecular magnets : Role of sulfur-to-selenium substitution2005

    • Author(s)
      A.Miyazaki et al.
    • Journal Title

      Phosphorus, Sulfur, and Silicon 180

      Pages: 883-890

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] π-d interaction-based molecular magnets : Role of sulfur-to-selenium substitution2005

    • Author(s)
      A.Miyazaki, K.Okabe, K.Enomoto, T.Enoki
    • Journal Title

      Phosphorus, Sulfur, and Silicon 180

      Pages: 883-890

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Crystal structure and physical properties of (EDO-TTFBr_2)_2FeX_4(X=Cl,Br)2004

    • Author(s)
      A.Miyazaki et al.
    • Journal Title

      J. Phys. IV. 114

      Pages: 545-547

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Crystal structure and physical properties of (EDO-TTFBr_2)_2FeX_4 (X=Br,Cl)2004

    • Author(s)
      A.Miyazaki, M.Aimatsu, H.Yamazaki, T.Enoki, K.Ugawa, E.Ogura, Y.Kuwatani, M.Iyoda
    • Journal Title

      J.Phys.IV France 114

      Pages: 545-548

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Magnetic TTF-Based Charge-Transfer Complexes2004

    • Author(s)
      T.Enoki, A.Miyazaki
    • Journal Title

      Chem.Rev. 104

      Pages: 5449-5477

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Anomalous metallic state of one-dimensional molecular conductor (EDO-TTFBr_2)_3I_32003

    • Author(s)
      A.Miyazaki et al.
    • Journal Title

      Phys. Rev. B 68(8)

      Pages: 085108-1-085108-4

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Anomalous metallic state of one-dimensional molecular conductor (EDO-TTFBr_2)_3I_32003

    • Author(s)
      A.Miyazaki, T.Kato, H.Yamazaki, T.Enoki, E.Ogura, Y.Kuwatani, M.Iyoda, J.Yamaura
    • Journal Title

      Phys.Rev.B 68(8)

      Pages: 085108

    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 「集積型金属錯体」II-3章2003

    • Author(s)
      榎 敏明, 宮崎 章
    • Total Pages
      7(273)
    • Publisher
      化学同人
    • Description
      「研究成果報告書概要(和文)」より

URL: 

Published: 2007-12-13  

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