2003 Fiscal Year Annual Research Report

低次元有機導体における磁場誘起超伝導現象の探索と解明

Research Project

Project/Area Number	15073225
Research Institution	National Institute for Materials Science
Principal Investigator	宇治進也独立行政法人物質・材料研究機構, ナノマテリアル研究所, ディレクター (80344430)
Co-Investigator(Kenkyū-buntansha)	寺嶋太一独立行政法人物質・材料研究機構, ナノマテリアル研究所, 主幹研究員 (40343834)
Keywords	有機伝導体 / 磁場誘起超伝導 / 強磁場 / 極低温
Research Abstract	2次元有機伝導体λ-(BETS)_2FeCl_4はゼロ磁場では反強磁性絶縁相(AFI)であるが、磁場を伝導面(ac面)に平行にかけると10Tで絶縁相から金属相(M)に転移した後、17T-42Tの範囲で超伝導(S)を示す磁場誘起超伝導体である。これらの系の磁場誘起超伝導はJaccarino-Peter効果でほぼ説明できる。実際にこの効果を取り入れたFisherの理論式を用いて、磁場誘起超伝導の温度-磁場相図をほぼ再現できる。一方、ClをBrと置換した試料λ-(BETS)_2FeCl_<4-x>Br_xでは,少なくともx>0.3の領域で、Feの磁化の温度変化に2段階の転移があり、M-I転移はその高温側の磁気転移に連動して起こることが報告されている。この2段階転移のメカニズムは明らかではないが、磁気転移とM-I転移が同時に起こることから、FeスピンとBETS上の伝導電子(π電子)スピンとが強く結合していることが示唆される。このBr置換試料の系統的な実験を行った。x=0.7では、磁場(c軸方向)をかけると、0.45Kでは、26T程度の磁場でAFI相からほとんど直接にS相へと転移することを見出した。温度の上昇とともに超伝導は急激に抑制され、2K以上では完全に消失する。抵抗の最小は33T程度にあり、この磁場でもっとも超伝導が安定していることが示唆される。x=0.7ではx=0と比較して絶縁相の領域がずっと高磁場まで安定していることが分かった。磁化の2段階転移に対応して、この絶縁相の中に相境界があるはずであるが、抵抗測定からはまだ判明していない。 x=0では量子振動の解析、相図の解析から、内部磁場が33T程度であり、そのために33T付近で超伝導転移温度が最大になることが分かっている。x=0.7でも最大超伝導転移温度は33T付近であり、33T程度の内部磁場を持つようである。この事実はClをBrに置換しても、Feスピンとπ電子スピンの交換相互作用は大きくは変化していないことを示している。Br置換によるM-I転移温度の上昇は、他の要因が関わっていると考えられる。

Research Products

(24 results)

All Other

All Publications (24 results)

[Publications] 宇治進也: "Global Phase Diagram of the magnetic Field-Induced Organic Superconductorsλ-(BEST)2FexGa1-xCl4"Journal of the Physical Society of Japan. 72. 369-373 (2003)
[Publications] 宇治進也: "Novel Electronic Properties under Magnetic Fields in Organic Conductorsλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 133. 481-483 (2003)
[Publications] 宇治進也: "Superconductivity in Organic Alloysλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 137. 1183-1185 (2003)
[Publications] 宇治進也: "Large Anisotropy in Magnetic Field Induced Superconductorsλ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)
[Publications] 川本正: "Incommensurate anion potential effect on the Electronic State of the Organic Superconductor(MDT-TSF)2(AuI2)0.436"Physical Review B. 67. (020508)1-(020508)4 (2003)
[Publications] J.S.Brooks: "Novel Features of the Newly Discovered Field-Induced Superconducting Phase ofλ-(BETS)2FeCl4"Synthetic Metals. 133. 485-486 (2003)
[Publications] W.Kang: "The Novel Role of Anion Ordering in Angle Dependent Magnetotoransport of One-Dimensional Organic Conductors"Synthetic Metals. 133. 15-16 (2003)
[Publications] 村田恵三: "Spin Density Wave under Uniaxial Strain in (TMTSF)PF6"Synthetic Metals. 133. 51-52 (2003)
[Publications] 安塚周麿: "Fermi Surface in New Layered Organic Conductors(BEDT-TTF) 3Br(pBlB)and(BEDT-TTF)3Cl(DFBlB)"Synthetic Metals. 133. 169-170 (2003)
[Publications] 安塚周麿: "Fermi Surface and Resistance Anomalies in ET-TCNQ"Synthetic Metals. 135-136. 647-648 (2003)
[Publications] 寺嶋太一: "Fermi Surface Studies of the Ferromagnetic Superconductor UGe2 under High Pressure"Acta Physica Polonica B. 34. 427-430 (2003)
[Publications] 遠藤元気: "Electronic Structures of PrPb3 in the Para-and Antiferroquadrupolar Phases"Acta Physica Polonica B. 34. 1031-1034 (2003)
[Publications] 宇治進也: "Large Anisotropy in Magnetic Field Indeced Superconductors λ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)
[Publications] 宇治進也: "Electronic state anisotropy and the Fermi surface topology of the Incommensurate organic superconducting crystal (MDT-TSF)(AuI2)0.436"European Physical Journal B. 36. 161-167 (2003)
[Publications] 海老原孝雄: "Dependence of the Effective Masses in YbAl3 on Magnetic Field and Disorder"Physical Review Letters. 90. (166404)1-(166404)4 (2003)
[Publications] 寺井慶和: "Size effect on vortex states in superconducting mesoscopic aluminum disks"Physica C. 329-333. 1419-1420 (2003)
[Publications] 宇治進也: "High field alloy, thermoelectric, and mm wave studies of the field induced superconducting state in λ-(BETS)2FexGa1-xCl4"Brazillan Journal of Physics. 33. 690-694 (2003)
[Publications] 矢ヶ部太郎: "Electron-electron interaction effect on conductivities in cobalt thin films"Physica B. 329-333. 1111-1112 (2003)
[Publications] 宇治進也: "Formation of metallic NbSe2 nanotubes and nanofibers"Current Applied Physics. 3. 473-476 (2003)
[Publications] 宇治進也: "Felmi Surface and Angular-Dependent magnetoresistance in the organic comductor(BEDT-TTF)2Br(DIA)"Physical Review B. 68. (064420)1-(064420)7 (2003)
[Publications] 宇治進也: "Magnetic field induced superconductor"OYO BUTURI. 72. 43-44 (2003)
[Publications] H.Kang: "Eveidence for coherent interchain electron transport in quasi-one-Dimensional molecular conductors"Physical Review B. 68. (132508)1-(132508)4 (2003)
[Publications] 宇治進也: "Large anisotropy in magnetic field induced superconductors λ-(BETE)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)
[Publications] 宇治進也: "Normal-state Hall Angle and Magnetoresistance in Quasi-2D Fermion CeCoIn5 near a Quantum Critical Point"Journal of the Physical Society of Japan. 73. 508 (2004)

2003 Fiscal Year Annual Research Report

低次元有機導体における磁場誘起超伝導現象の探索と解明

Principal Investigator

宇治 進也 独立行政法人物質・材料研究機構, ナノマテリアル研究所, ディレクター (80344430)

Research Products

[Publications] 宇治 進也: "Global Phase Diagram of the magnetic Field-Induced Organic Superconductorsλ-(BEST)2FexGa1-xCl4"Journal of the Physical Society of Japan. 72. 369-373 (2003)

[Publications] 宇治 進也: "Novel Electronic Properties under Magnetic Fields in Organic Conductorsλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 133. 481-483 (2003)

[Publications] 宇治 進也: "Superconductivity in Organic Alloysλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 137. 1183-1185 (2003)

[Publications] 宇治 進也: "Large Anisotropy in Magnetic Field Induced Superconductorsλ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 川本 正: "Incommensurate anion potential effect on the Electronic State of the Organic Superconductor(MDT-TSF)2(AuI2)0.436"Physical Review B. 67. (020508)1-(020508)4 (2003)

[Publications] J.S.Brooks: "Novel Features of the Newly Discovered Field-Induced Superconducting Phase ofλ-(BETS)2FeCl4"Synthetic Metals. 133. 485-486 (2003)

[Publications] W.Kang: "The Novel Role of Anion Ordering in Angle Dependent Magnetotoransport of One-Dimensional Organic Conductors"Synthetic Metals. 133. 15-16 (2003)

[Publications] 村田 恵三: "Spin Density Wave under Uniaxial Strain in (TMTSF)PF6"Synthetic Metals. 133. 51-52 (2003)

[Publications] 安塚 周麿: "Fermi Surface in New Layered Organic Conductors(BEDT-TTF) 3Br(pBlB)and(BEDT-TTF)3Cl(DFBlB)"Synthetic Metals. 133. 169-170 (2003)

[Publications] 安塚 周麿: "Fermi Surface and Resistance Anomalies in ET-TCNQ"Synthetic Metals. 135-136. 647-648 (2003)

[Publications] 寺嶋 太一: "Fermi Surface Studies of the Ferromagnetic Superconductor UGe2 under High Pressure"Acta Physica Polonica B. 34. 427-430 (2003)

[Publications] 遠藤 元気: "Electronic Structures of PrPb3 in the Para-and Antiferroquadrupolar Phases"Acta Physica Polonica B. 34. 1031-1034 (2003)

[Publications] 宇治 進也: "Large Anisotropy in Magnetic Field Indeced Superconductors λ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 宇治 進也: "Electronic state anisotropy and the Fermi surface topology of the Incommensurate organic superconducting crystal (MDT-TSF)(AuI2)0.436"European Physical Journal B. 36. 161-167 (2003)

[Publications] 海老原 孝雄: "Dependence of the Effective Masses in YbAl3 on Magnetic Field and Disorder"Physical Review Letters. 90. (166404)1-(166404)4 (2003)

[Publications] 寺井 慶和: "Size effect on vortex states in superconducting mesoscopic aluminum disks"Physica C. 329-333. 1419-1420 (2003)

[Publications] 宇治 進也: "High field alloy, thermoelectric, and mm wave studies of the field induced superconducting state in λ-(BETS)2FexGa1-xCl4"Brazillan Journal of Physics. 33. 690-694 (2003)

[Publications] 矢ヶ部 太郎: "Electron-electron interaction effect on conductivities in cobalt thin films"Physica B. 329-333. 1111-1112 (2003)

[Publications] 宇治 進也: "Formation of metallic NbSe2 nanotubes and nanofibers"Current Applied Physics. 3. 473-476 (2003)

[Publications] 宇治 進也: "Felmi Surface and Angular-Dependent magnetoresistance in the organic comductor(BEDT-TTF)2Br(DIA)"Physical Review B. 68. (064420)1-(064420)7 (2003)

[Publications] 宇治 進也: "Magnetic field induced superconductor"OYO BUTURI. 72. 43-44 (2003)

[Publications] H.Kang: "Eveidence for coherent interchain electron transport in quasi-one-Dimensional molecular conductors"Physical Review B. 68. (132508)1-(132508)4 (2003)

[Publications] 宇治 進也: "Large anisotropy in magnetic field induced superconductors λ-(BETE)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 宇治 進也: "Normal-state Hall Angle and Magnetoresistance in Quasi-2D Fermion CeCoIn5 near a Quantum Critical Point"Journal of the Physical Society of Japan. 73. 508 (2004)

宇治進也独立行政法人物質・材料研究機構, ナノマテリアル研究所, ディレクター (80344430)

[Publications] 宇治進也: "Global Phase Diagram of the magnetic Field-Induced Organic Superconductorsλ-(BEST)2FexGa1-xCl4"Journal of the Physical Society of Japan. 72. 369-373 (2003)

[Publications] 宇治進也: "Novel Electronic Properties under Magnetic Fields in Organic Conductorsλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 133. 481-483 (2003)

[Publications] 宇治進也: "Superconductivity in Organic Alloysλ-(BETS)2FexGa1-xCl4"Synthetic Metals. 137. 1183-1185 (2003)

[Publications] 宇治進也: "Large Anisotropy in Magnetic Field Induced Superconductorsλ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 川本正: "Incommensurate anion potential effect on the Electronic State of the Organic Superconductor(MDT-TSF)2(AuI2)0.436"Physical Review B. 67. (020508)1-(020508)4 (2003)

[Publications] 村田恵三: "Spin Density Wave under Uniaxial Strain in (TMTSF)PF6"Synthetic Metals. 133. 51-52 (2003)

[Publications] 安塚周麿: "Fermi Surface in New Layered Organic Conductors(BEDT-TTF) 3Br(pBlB)and(BEDT-TTF)3Cl(DFBlB)"Synthetic Metals. 133. 169-170 (2003)

[Publications] 安塚周麿: "Fermi Surface and Resistance Anomalies in ET-TCNQ"Synthetic Metals. 135-136. 647-648 (2003)

[Publications] 寺嶋太一: "Fermi Surface Studies of the Ferromagnetic Superconductor UGe2 under High Pressure"Acta Physica Polonica B. 34. 427-430 (2003)

[Publications] 遠藤元気: "Electronic Structures of PrPb3 in the Para-and Antiferroquadrupolar Phases"Acta Physica Polonica B. 34. 1031-1034 (2003)

[Publications] 宇治進也: "Large Anisotropy in Magnetic Field Indeced Superconductors λ-(BETS)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 宇治進也: "Electronic state anisotropy and the Fermi surface topology of the Incommensurate organic superconducting crystal (MDT-TSF)(AuI2)0.436"European Physical Journal B. 36. 161-167 (2003)

[Publications] 海老原孝雄: "Dependence of the Effective Masses in YbAl3 on Magnetic Field and Disorder"Physical Review Letters. 90. (166404)1-(166404)4 (2003)

[Publications] 寺井慶和: "Size effect on vortex states in superconducting mesoscopic aluminum disks"Physica C. 329-333. 1419-1420 (2003)

[Publications] 宇治進也: "High field alloy, thermoelectric, and mm wave studies of the field induced superconducting state in λ-(BETS)2FexGa1-xCl4"Brazillan Journal of Physics. 33. 690-694 (2003)

[Publications] 矢ヶ部太郎: "Electron-electron interaction effect on conductivities in cobalt thin films"Physica B. 329-333. 1111-1112 (2003)

[Publications] 宇治進也: "Formation of metallic NbSe2 nanotubes and nanofibers"Current Applied Physics. 3. 473-476 (2003)

[Publications] 宇治進也: "Felmi Surface and Angular-Dependent magnetoresistance in the organic comductor(BEDT-TTF)2Br(DIA)"Physical Review B. 68. (064420)1-(064420)7 (2003)

[Publications] 宇治進也: "Magnetic field induced superconductor"OYO BUTURI. 72. 43-44 (2003)

[Publications] 宇治進也: "Large anisotropy in magnetic field induced superconductors λ-(BETE)2FexGa1-xCl4"Physica C. 388-389. 611-612 (2003)

[Publications] 宇治進也: "Normal-state Hall Angle and Magnetoresistance in Quasi-2D Fermion CeCoIn5 near a Quantum Critical Point"Journal of the Physical Society of Japan. 73. 508 (2004)