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magnetic field induced metal-nonmetal transition in organic conductors

Research Project

Project/Area Number 05452061
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionToho University

Principal Investigator

KAJITA Koji  Toho University, Department of Physics, Professor, 理学部, 教授 (50011739)

Co-Investigator(Kenkyū-buntansha) NISHIO Yutaka  Toho University, Department of Physics, Professor, 理学部, 助教授 (20172629)
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1993: ¥6,300,000 (Direct Cost: ¥6,300,000)
KeywordsOrganic Conductor / Magnetoresistance / Hall effect / Metal-nonmetal Transition
Research Abstract

Two experiments were done in 1994. In the first one we examined if the magnetic field induced metal-nonmetal transition occurs in alpha- (BEDT-TSeF) _2I_3 of which the crystal structure and the electronic energy structure is very similar to those of alpha- (BEDT-TTF) _2I_3. The experimental results indicate that the field induced metal-nonmetal transition takes place in this materials as well as in alpha- (BEDT-TTF) _2I_3. However, the magnetic field strength about one order of magnitude higher was necessary to induce the transition. This may be due to low carrier mobility in this material.
The next problem concems with the transport properties in the metallic region. We measured the conductivity and the Hall effect simultaneously in the temperature region above the metal-nonmetal transition. We found that the carrier density of this material decreases with the decreasing temperature, while the carrier mobility increases. The effect of the change in the carrier density and the mobility just canceled out to give the temperature independent conductivity. This is just the same we observed in alpha- (BEDT-TSeF) _2I_3.
In the second experiment, we reexamined the low temperature Hall effect in alpha-(BEDT-TTF) _2I_3. A very large Hall angle observed at low temperatures suggests the fairly high carrier mobility in this material
Throughout the present project, we come to the conclusion that the magnetic field induced metal-nonmetal transition takes place in alpha- (BEDT-TTF) _2I_3 and alpha- (BEDT-TSeF) _2I_3 placed under high pressures and at low temperatures.

Report

(3 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] 尾日吏,梶田晃示,西尾豊,小林速男,小林昭子,加藤礼三,家泰弘: "An Anomalms Magnetoresistance in α-(BEDT-TTF)_2I_3 under High Pressure:A Possible New Phase" Physica. B184. 494-497 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 三島孝博,梶田晃示,西尾豊,家泰弘: "Extremely High Mability Carriers in Organic Conductor α-(BEDT-TTF)_2I_3 under High Pressure" Materials Science and Engineering. B25. L1-L5 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 飯森茂,梶田晃示,西尾豊,家泰弘: "Anomalous Metal-Insulator Trausition in α-(BEDT-TTF)_2I_3 under High Pressure" Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 西尾豊,手賀俊樹,梶田晃示,小林速男,小林昭子,青沼秀児,澤博,加藤礼三: "Giant Peak in the Specific Heat of Selectively Deuterated (DMe-DCNQI)_2Cu" Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 手賀俊樹,西尾豊,梶田晃示,加藤礼三,小林速男: "Magnetic Praperties of (DMe-DCNQI)_2Cu under Uniaxial Stress" Synthetic Metals. 印刷中.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 三島孝博,尾日吏,梶田晃示,西尾豊,家泰弘: "Temperature Independent Conductiuity of,α-(BEDT-TTF)_2I_3-Compensation of the changein the Carrier Density and the Mobility" Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Mishima, K.Kajita, Y.Nishio and Y.Iye: ""Extremely High Mobility Carriers in Organic Conductor alpha- (BEDT-TTF) _2I_3 under High Pressure"" Materials Science and Engineering. B25. L1-L5 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] S.Iimori, K.Kajita, Y.Nishio and Y.Iye: ""Anomalous Metal-Insulator Transition in alpha- (BEDT-TTF) _2I_3 under High Pressure"" Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Y.Nisho, T.Tega, K.Kajita, H.Kobayashi, S.Aonuma, H.Sawa and R.Kato: ""Giant Peak in the Specific Heat of Selectively Deuterated (DMe-DCNQI) _2Cu"" Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Tega, Y.Nishio, K.Kajita, R.Kato and H.Kobayashi: ""Magnetic Properties of (DMe-DCNQI) _2Cu under Uniaxial Stress"" Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Mishima, T.Ojiro, K.Kajita, Y.Nishio and Y.Iye": ""Temperature Independent Conductivity of alpha- (BEDT-TTF) _2I_3-Compensation of the Change in the Carrier density and the Mobility-" Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 三島 孝博,梶田 晃示 西尾 豊,家 泰弘: "Extremely Higbmalility Carriers in Organic Conductor α-(BET)T-TTFl_2I_3under High Pressure" Matrials Scieaces and Engineering. B25. L1-L5 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 飯森 茂,梶田 晃示,西尾 豊 家 泰弘: "ancmalns Metal-Insulator Trauitin in α-(βEDT-TTF)_2I_3 under High Pressure" Synthetic Metals. (印刷中).

    • Related Report
      1994 Annual Research Report
  • [Publications] 西尾 豊,手賀 俊樹,梶田 晃示 小林 速男,青沼 秀児.澤 博,加藤 礼三: "Giant Peak in the Specific Heat of Selectiuely Llauterated(DMe-DCNQI)_2Cu" Synthetic Metals. (印刷中).

    • Related Report
      1994 Annual Research Report
  • [Publications] 手賀 俊樹,西尾 豊,梶田 晃示 加藤 礼三,小林 速男: "Magnetic propertion of (DMe-DCNQI)_2Cu Under" Synthetic Metals. (印刷中).

    • Related Report
      1994 Annual Research Report
  • [Publications] 三島 孝博,尾日 史,梶田 晃示 西尾 豊,家 泰弘: "Temperature Independent Conductiuity of α-(BEDT-TTF)_2I_3-Cevpeneatin of tbe Change in the Carrien Lleuicty and the Mability" Synthetic Metals. (印刷中).

    • Related Report
      1994 Annual Research Report
  • [Publications] T.Mishima,K.Kajita他: "Extremely High Mohility Carriers in Organic Conductord -(BET)T-TTF)_2I_3" Materials Scence and Evgineering,B. (印刷中). (1994)

    • Related Report
      1993 Annual Research Report

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Published: 1993-04-01   Modified: 2020-05-15  

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