高温有機超伝導体の開発

1991 Fiscal Year Annual Research Report

• Project/Area Number: 63060004
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: 池本 勲 東京都立大学, 理学部, 教授 (00011601)
• Co-Investigator(Kenkyū-buntansha): 齋藤 軍治 京都大学, 理学部, 教授 (40132724)
• Keywords: 有機超伝導体 / ラジカル塩 / BEDTーTTF / DMET / 非対称電子供与体 / 電気伝導度 / 相転移 / 同位体効果

Research Abstract

1.前年に引き続き多数の陰イオンとBEDTーTTFなどのドナ-との錯体単結晶を作成した.2種の新規BEDTーTTF有機超伝導体を初め,24種の金属的伝導体を開発し,それらの結晶構造,電導造,超伝導性を研究した.新超伝導体は共にκ型のドナ-配列を持ち,κー(BEDTーTTF)^2Cu(CN)[N(CN)_2],κ'ー(BEDTーTTF)_2Cu_2(CN)_3と示される.前者のTcは我々が1987年に見いだしたκー(BEDTーTTF)_2Cu(NCS)_2のTc=10.4Kより約1K高い11.2Kである.室温での伝導異方性は約230で,κー(BEDTーTTF)_2Cu(NCS)_2(異方性600)より三次元性が強く,κー(BEDTーTTF)_2Cu[N(CN)_2]Br(異方性200,Tc=11.8K)と同程度である.二次元面内での上部臨界磁場は1.5Kで21テスラでPauli limitを越えている.陰イオンは一次元的ポリマ-鎖を成し,薄い絶縁層を形成する.ポリマ-鎖間に短い原子接触が存在しないので,陰イオン構造は一次元的である.ホ-ル(二次元)と電子(一次元)によるフェルミ面が共存し,その二種のフェルミ面間にギャップが存在する.κ'ー(BEDTーTTF)_2Cu_2(CN)_3のTcは常圧で3.8Kである.伝導異方性は約400で,電子状態の三次元性はκー(BEDTーTTF)_2Cu(CN)[N(CN)_2]錯体より小さい.陰イオン絶縁層は二次元蜂の巣構造の陰イオンポリマ-よりなる.
2.炭素原子のみからなるフラ-レンを用いた超伝導体の探索を行った.始めにHPLCによる能率的なフラ-レンの分離法を確立し,この方法により炭素数76以上のフラ-レンも1カ月で150mg程度分離精製することが可能となった.同時に溶媒としてCS_2を用い,良質のC_<60>単結晶を作成することを見いだし,この試料を用い,KやRbをド-プすることで,超伝導性を示すことを電気抵抗の測定から確認した.転移温度より高温では負イオンのキャリヤ-をもつ金属であることを見いだした.

Research Products

• [Publications] K.Kobayashi: "Novel Conducting Copper Complex Based on Thiophen-fused DCNQI" Chem.Lett.1991. 1033-1036 (1991)
• [Publications] K.Kobayashi: "Novel Copper Complexes Based on Thiophen-Fused DCNQI" Synthetic Metals. 41-43. 1847-1850 (1991)
• [Publications] K.Kikuchi: "Conducting Salts Based on Some Unsymmetrical Donors" Synthetic Metals. 41-43. 1921-1924 (1991)
• [Publications] K.Kikuchi: "Reflectance Spectra of (DMET) _2X" Synthetic Metals. 41-43. 2275-2280 (1991)
• [Publications] K.Saito: "Thermoelectric Power of (DMET) _2X" Synthetic Matals. 41-43. 2395-2398 (1991)
• [Publications] A.A.Zakhidov: "Evolution of Superconductivity of K_XC_<60> Upon K-Doping:Microwave Low-Field Signal and ESR Study" Solid State Commun.79. 939-946 (1991)
• [Publications] K.Kanoda: "Antiferromagnetic Transition in the Organic Conductors Based on Asymmetric Donors" Synthetic Metals. 41-43. 1679-1682 (1991)
• [Publications] T.Atake: "Heat Capacity Measurements and Thermodynamic Studies of the New Compound C_<60>" Phisica C. 185-189. 427-428 (1991)
• [Publications] Y.Fukuda: "Electronic States of Core Levels and Valence Bands for KxC_<60> Studied by X-Ray Photoelectron Spectroscopy" Phisica C. 181. 320-324 (1991)
• [Publications] Y.Ishikawa: "Crystal Structure of the Organic Metal (DMET) _2BF_4 with Two Columns along Two Crystallographic Axes"" Bull.Chem.Soc.Jpn.64. 212-215 (1991)
• [Publications] M.Ishibashi: "Hall Effect in (DMET) _2I_3 under pressure" Synthetic Metals. 41-43. 2167-2170 (1991)
• [Publications] K.Kikuchi: "Separation,Detection,and UV/Visible Absorption Spectra of Fullerenes;C_<76>,C_<78> and C_<84>" Chem.Lett.1991. 1607-1610 (1991)
• [Publications] Y.Maruyama: "Observation of Metallic Conductivity and Sharp Superconducting Transition at 19K in Potassium-Doped Fulleride,C_<60>,Single Crystal" Chem.Lett.1991. 1849-1852 (1991)
• [Publications] Y.Maniwa: "NMR investigation on the CS_2-and Benzen-Grown C_<60> Crystals" Solid State Commun.80. 609-612 (1991)
• [Publications] Y.Maruyama: "Electronic Properties of C_<60> and Alkali Metal Doped C_<60> Thin Films or Single Crystal" Phisica C. 185-189. 413-414 (1991)
• [Publications] K.Kikuchi: "Structure and Superconductivity of Single Crystalline C_<60>" Phisica C. 185-189. 415-416 (1991)
• [Publications] T.Takahashi: "Photoemission Study of C_<60> and its Alkali-Metal Compounds" Phisica C. 185-189. 417-418 (1991)
• [Publications] N.A.Fortune: "Calorimetric Observation of a Structural Phase Transition at Elevated Temperature in single Crystal C_<60>" Phisica C. 185-189. 425-426 (1991)
• [Publications] M Murata: "Hall Effect of Organic Superconductors of (TMTSF) _2X,(DMET) _2X and (BEDT-TTF) _2X" Phisica C. 185-189. 2685-2686 (1991)
• [Publications] A.Otsuka: "C_1 TET-TTF Salts with Octahedral Anions" Synthetic Metals. 42. 1699-1702 (1991)
• [Publications] Y.Yamochi: "The Cation Radical Salts of Oxygen-Substituted Donor,BEDO-TTF" Synthetic Metals. 42. 1741-1744 (1991)
• [Publications] P.Wang: "Electrical and Magnetic Properties of Tetrakis(methylseleno)tetrathiafulvalene (TSeC_1-TTF) _xHgBr_2 Complex Salt" Synthetic Metals. 42. 1949-1952 (1991)
• [Publications] I.Shirotani: "Electrical and Optical Anomalies in One-Dimensional Complex Bis(1,2-benzoquinonedioximato)Pt(II) at High Pressure" Synthetic Metals. 42. 2415 (1991)
• [Publications] H.Mori: "Structural and Physical Properties of (BEDTーTTF) _3Li_<0.5>Hg(SCN) _4(H_2O)_2 and α"ー(BEDTーTTF) _2CsHg(SCN)_4" Solid State Commun.78. 49-54 (1991)
• [Publications] G.Saito: "Recent Progress in Organic Superconductors" Physica B. 169. 372-376 (1991)
• [Publications] N.Hino: "Observation of Narrow Band Noise and Field-Hysteresis in the Spin-Density-Wave Phase of (TMTSF) _2PF_6" Synthetic Metals. 40. 275-281 (1991)
• [Publications] T.Osada: "Commensurability Effect of Magnetoresistance Anisotropy in a Quasi-One-Dimensional Conductor Tetramethyltetraselenafulvalenium Perchlorate (TMTSF) _2ClO_4" Phys.Rev.Lett.66. 1525-1528 (1991)
• [Publications] Y.Mori: "Electronic Structure of (BEDT-TTF) _2X Salts Studied by Scanning Tunneling Spectroscopy" Jpn.J.Appl.Phys.30. 358-360 (1991)
• [Publications] M.Hasumi: "Possible Origins of the Difference in the Critical Temperature of Three Superconducting States in βー(BEDTーTTF) _2I_3" Synthetic Metals. 42. 1971-1976 (1991)
• [Publications] G.Saito: "Overview of Organic Superconductor κー(BEDTーTTF) _2[Cu(NCS)_2] and Its Related Materials" Synthetic Metals. 42. 1993-1998 (1991)
• [Publications] T.Takahashi: "Unconventional Superconductivity in the Organic Superconductor,κー(BEDTーTTF) _2Cu(NCS)_2" Synthetic Metals. 42. 2005-2012 (1991)
• [Publications] K.Imaeda: "Crystal Structures and Electrical Conductivities of TXCnーTTF (X=Sulfur,Selenium,Tellurium;n=2,3)・TCNQ ChargeーTransfer Complexes" Bull.Chem.Soc.Jpn.64. 2159-2168 (1991)
• [Publications] T.Ida: "Pressure Dependence of the Polarized Reflectance Spectrum of a Solid Charge-Transfer Complex,Perylene-Hexacyanobutadiene(HCBD)" Chem.Phys.156. 113-122 (1991)
• [Publications] Y.Iwasa: "Nonlinear Soliton Transport in Charge Transfer Compounds" Synthetic Metals. 42. 1675-1678 (1991)
• [Publications] Y.Iwasa: "Neutral-Ionic Transition in TTF-Chloranil and TMB-TCNQ" Synthetic Metals. 42. 1827-1830 (1991)
• [Publications] S.Koshihara: "Domain Wall Excitation in Organic Charge Transfer Compounds Investigated by Photo-Reflectance Spectroscopy" Synthetic Metals. 42. 2351-2354 (1991)
• [Publications] Y.Moritomo: "One-Dimensional Ferroelectricity and Dynamics of Domain-Walls in Organic Compounds" Synthetic Metals. 43. 3275-3278 (1991)
• [Publications] H.Okamoto: "Anomalous Dielectric Response in Tetrathiafulvalene-p-Chloranil as Observed in Temperature-and Pressure Induced Neutral-to-Ionic Phase Transition" Phys.Rev.B. 43. 8224-8232 (1991)
• [Publications] G.Saito: "Frontiers of Organic Superconductors" "Lower-Dimensional Systems and Molecular Electroncs" Ed.R.M.Metzger,P.Day,G.C.Papavassiliou,NATO ASI Series,Plenum Press,New York. 73-90 (1991)
• [Publications] H.Mori: "Electrical Properties and Crystal Structures of Mercury(II) Thiocyanate Salts Based upon BEDT-TTF with Li_+,K_+,NH4_+,Rb_+,and Cs_+" Synthetic Metals. 42. 2013-2018 (1991)
• [Publications] K.Kanoda: "Annealing Effect on the Superconductivity of βー(BEDTーTTF) _2I_3" Synthetic Metals. 42. 2087-2090 (1991)
• [Publications] H.Mori: "Upper Critical Field and Critical Current Density of Organic Superconductor,κー(BEDTーTTF) _2Cu(NCS)_2" Synthetic Metals. 42. 2159-2162 (1991)
• [Publications] T.Osada: "Fermiology and Unusual High-Field Megnetotransport in Novel Organic Metals (BEDT-TTF) _2XHg(SCN)_4 (X=K,NH_4)" Synthetic Metals. 42. 2171-2174 (1991)
• [Publications] K.Oshima: "Fermi Surface Modulation by Pressure in κー(BEDTーTTF) _2Cu(NCS)_2" Synthetic Metals. 42. 2175-2178 (1991)
• [Publications] T.Osada: "Fine Structure of Magnetoresistance Anisotropy in a Quasi-One-Dimensional Organic Conductor (TMTSF) _2ClO_4" Synthetic Metals. 42. 2385-2388 (1991)
• [Publications] T.Takahashi: "Inner Structure of the Low Field SDW State of (TMTSF) _2PF_6" Synthetic Metals. 43. 3985-3988 (1991)
• [Publications] T.Doi: "Anomalous Temperature Dependent Local Structure in κー(BEDTーTTF) _2Cu(NCS)_2" J.Phys.Soc.Jpn.60. 1441-1444 (1991)
• [Publications] H.Ito: "Magnetic Determination of GinzburgーLandau Coherence Length for Organic Supercondutor κー(BEDTーTTF) _2X (X=Cu(NCS)_2,Cu[N(CN)_2]Br):Effect of Isotope Substitution" J.Phys.Soc.Jpn.60. 3230-3233 (1991)
• [Publications] M.Yoshimura: "Electronic Structure of the Organic Superconductor κー(BEDTーTTF) _2Cu(NCS)_2 [where BEDTーTTF is bis (ethylenedithio)tetrathiafulvalene] Studied by Scanning Tunneling Microscopy" Phys.Rev.B. 43. 13590-13593 (1991)
• [Publications] M.Yoshimura: "Surface Structure of the Organic Conductor βー(BEDTーTTF) _2I_3 Observed by Scanning Tunneling Microscopy [where BEDTーTTF is bis(ethylenedithio)tetrathiafulvalene]" Phys.Rev.B. 44. 1970-1972 (1991)
• [Publications] M.Yoshimura: "The Surface Structure of an Organic Conductor (BEDTーTTF) _2KHg(SCN)_4 Observed by Scanning Tunneling Microscopy" Surf.Sci.242. 18-22 (1991)
• [Publications] Y.J.Uemura: "Basic Similarities among Cuprate,Bismuthate,Organic,Chevrel Phase,and Heavy-Fermion Superconductors Shown by Penetration Depth Measurements" Phys.Rev.Lett.66. 2665-2668 (1991)
• [Publications] T.Takahashi: "Novel Aspect of Organic Superconductors:NMR and Magnetic Susceptibility" Physica C. 185-189. 366-371 (1991)
• [Publications] H.Ito: "Superconducting Transition in κー(BEDTーTTF) _2Cu[N(CN)_2]Br Under Magnetic Field" Physica C. 185ー189. 2659-2660 (1991)
• [Publications] K.Kanoda: "NMR Study of an Organic Superconductor" Physica C. 185-189. 2667-2668 (1991)
• [Publications] T.Doi: "EXAFS Study in Organic Superconductors" Physica C. 185-189. 2671-2672 (1991)
• [Publications] M.Hasumi: "Experimental Studies of Three Superconducting States in the Organic Superconductor βー(BEDTーTTF) _2I_3" Physica C. 185ー189. 2675-2676 (1991)
• [Publications] T.Osada: "Novel Fermi-Surface Topological Effects of Magnetoresistance Anisotropy in Low-Dimensional Organic Superconductors" Physica C. 185-189. 2697-2698 (1991)
• [Publications] T.Komatsu: "New Ambient Pressure Organic Superconductors Based on BEDT-TTF,Cu,N(CN)_2 and CN with Tc=10.7 and 3.8K" Solid State Commun.80. 843-847 (1991)
• [Publications] M.Yudasaka: "Formation of Highly Oriented Thin Films of TTF_7I_5 and Their Properties" Synthetic Metals. 42. 1527 (1991)
• [Publications] J.K.Jeszka: "Thermal Properties of Tetrakis(alkyltelluro)tetrathiafulvalene (TTeCn-TTF)" Mol.Cryst.Liq.Cryst.196. 167-175 (1991)
• [Publications] C.Nakano: "Phase Transition of Tetrakis(octylthio)tetrathiafulvalene (TTC8-TTF) and Crystal Structure Analysis" J.Mater.Chem.,. 1. 37-41 (1991)