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1998 Fiscal Year Final Research Report Summary

Thermodynamic Investigation of the Gap Structure and Electron Pair-Symnetry in Organic Superconductors

Research Project

Project/Area Number 09640450
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionOkazaki National Research Institutions

Principal Investigator

NAKAZAWA Yasuhiro  Institute for molecular Science, Department of Molecular Assemblies, Research Associate, 分子科学研究所, 助手 (60222163)

Project Period (FY) 1997 – 1998
KeywordsSuperconductivety / Specific Heat / Organic Conductor
Research Abstract

This research project aims at clarifying the structure of energy gap in the superconductive states of BEDT-TTF based organic superconductors through analyses of specific heat data. To get detail information on the ground state and the low-energy excitations from it, we performed the experiment at extremely low-temperature region below IK. We have improved a sample cell for the thermal-relaxation type calorimeter equipped with the dilution refrigerator at Institute for Molecular Science. As a consequence, we have succeeded to reduce the heat capacity of addenda part down to about 0.1μJ/K at 1K, which is satisfactory small to get enough resolution. For the system of κ-(BEDT-TTF)ィイD22ィエD2X [X=Cu[N(CN)ィイD22ィエD2]Br, Cu(NCS)ィイD22ィエD2] ,we have discussed the temperature dependence of specific heat and magnetic fields dependence of electronic specific-heat coefficient, γ up to 10T and also discuss the residual γ* term in the superconductive state. The results suggest that the gap-structure of this system can be explained within the frame of line-nodes picture of d-wave superconductors. It is however to be mentioned that the γ(H) curves of both salts show a kink around 2T, which may be related to the vortex states of these materials. We are going to further inquire into the magnetic fields dependence of this γ in order to clarify the pairing nature and vortex state in detail.

  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] Y. Nakazawa and K. Kanoda: "Low-temperature Specific Heat of k-(BEDT-TTF)_2Cu[N(CN_2]Br in the Superconducting State"Physical Review B. 55. R8670-R8673 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Nakazawa and K. Kanoda: "Low-Temperature Specific Heat Studies on Superconductors and Mott Insulators in k-(BEDT-TIF)_2X System"Synthetic Metals. 85. 1563-1564 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Nakazawa and K. Kanoda: "Thermodynamic Property of Organic Superconductor k-(BEDT-TTF)_2X _2"Physica C. 282-287. 1897-1898 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Taniguchi, Y. Nakazawa and K. Knanoda: "Phose Diagram of Vortices in the Quasi-Two-Dimensional Organic Superconductor α-(BEDT-TTF)NH_2Hg(SCN)_2 : A System of Pancake Vortices with Out-of-Plane Coupling Dominated by the Electromagnetic Energy"Physical Review B. 57. 3623-3634 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Nakazawa and K. Kanoda: "Thermodynamic Investigation on of the Electoronic States of Deuterated k-(BEDT-TTF)_2X _2"Physical Review B. 60. 4263-4267 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Nakazawa and K. Kanoda: "Thermodynamics of BEDFTTF Based Dimeric Salts"Synthetic Metals. 103. 1903-1904 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Low-temperature Specific Heat of k-(BEDT-TTF)2Cu[N(CN)2]Br in the Superconducting State"Phys. Rev.. B55. R8670-8673 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Reply to the "Comment on 'Electronic Structure of Insulating Slts of the k-(BEDT-TTF)2x Faily Studied by Low-Temperature Specific Heat Measurements'""Synthetic Metals. B56. 951-952 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Low-Temperature Specific Heat Studies on Superconductors and Mtt Insulators in k-(BEDT-TTF)2X System"Synthetic Metals. 85. 1563-1564 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Thermodynamic Property of Organic Property of Organic Superconductor k-(BEDT-TTF)2X[X=Cu9NCS)2, Cu[N(CN)2Br]"Physica C. 282-287. 1897-1898 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S. MIYAJIMA and T. NAKAI: "Serise: Experimental Spectroscopy of Liquid Crystals pt. 3 NMR Spectroscopy Pt. 1 (in japanese)"Ekisho (Journal of the Japanese Liquid Crystal Society). 3-1. 43-51 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H. Taniguchi, Y. Nakazawa and K. Kanoda: "Phase Diagram of Vortices in the Quasi-Two-Dimensional Organic Superconductor a-(BEDT-TTF)2NH4HG(SCN)4: A System of Pancake Vortices with Out-of-Plane Coupling Dominated by the Electromagnetic Energy"Phys. Rev.. B57. 3623-3634 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Thermodynamic Investigation of the Electronic States of Deuterated k-(BEDT-TTF)2CU[N(CN)2]Br"Phys. Rev.. B60. 4263-4267 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa and k. Kanoda: "Thermodynamics of BEDT-TTF based Dimeric Salts"Synthetic Metals. 103. 1903-1904 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Nakazawa, H. Taniguchi, A., Kawanoto and k. Kanoda: "Electronic Specific heat of BEDT-TTF Based Organic Conductors"Physica B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2001-10-23  

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