2000 Fiscal Year Annual Research Report

量子フラストレーション系の物質探索・創製

Research Project

Project/Area Number	12046221
Research Category	Grant-in-Aid for Scientific Research on Priority Areas (A)
Research Institution	The University of Tokyo
Principal Investigator	高木英典東京大学, 大学院・新領域創成科学研究科, 教授 (40187935)
Co-Investigator(Kenkyū-buntansha)	菅野了次神戸大学, 理学部, 助教授 (90135426) 広井善二東京大学, 物性研究所, 助教授 (30192719) 上田寛東京大学, 物性研究所, 教授 (20127054)
Keywords	強相関電子系 / 遷移金属酸化物 / 幾何学的フラストレーション / 低次元性 / 金属-絶縁体転移 / 電荷整列 / 量子磁性 / 超伝導
Research Abstract	本研究の主題は、磁性を担うスピンが固体(磁気秩序)にならず、一種の液体状態(量子スピン液体)を示す舞台(幾何学的フラストレーション系、低次元系)を積極的に開発し、そこに伝導キャリアを導入する事により、エキゾチック物性の開拓することである。具体的な成果として、3次元のフラストレーション系であるスピネル・パイロクロア格子、1次元系などにおいて、新規物性・新物質が見出された。スピネル型LiV_2O_4において重い電子状態形成を検証し、幾何学的フラストレーョンに起因するスピン液体状態がその背景にあることを実験的に示した。混合原子価スピネル・パイロクロア化合物における「電荷フラストレーション」の概念を提唱した。スピネル型AlV_2O_4において、電荷フラストレーションの存在下で生じる新規な電荷整列状態を発見した。さらに、オスミウムを含むパイロクロア型酸化物における金属絶縁体転移に着目し、その化学置換による変化を調べている。バナジウム酸化物やコバルト酸化物の合成と単結晶育成をはかり、構造評価および電子物性評価を行った。擬一次元導体b-Na_<1/3>V_2O_5では大型単結晶育成に成功し、中性子回折により反強磁性磁気秩序構造を決定した。また、高圧下で、金属-絶縁体転移が抑えられ、超伝導状態が出現することを見出した。酸素欠損型ペロフスカイト化合物YBaCo_2O_<5+x>においては、酸素不定比性を制御し、空格子点規則配列構造をもつ三つの相が存在することを見出した。また、これらの化合物が、電荷整列転移や相分離現象、金属-絶縁体転移、磁気転移、巨大磁気抵抗効果などを示すことを発見した。

Research Products

(32 results)

All Other

All Publications (32 results)

[Publications] K.Ohwaka H.Nakao,H.Nakatogawa,N.Takesue et al.: "Pressure-Induced Phase Transition in NaV2O5 at Low Temperature"J.Phys.Soc.Jpn.. 69. 639-642 (2000)
[Publications] M.Itoh,N.Akimoto,M.Tsuchiya,H.Yamada,M.Isobe and Y.Ueda: "51V NMR study of charge ordering in AV6O15(A=Ca,Na andAg)."Physica B. 281-282. 606-607 (2000)
[Publications] Z.V.Popvic,R.Gajic,M.J.Konstantinovic,R.Provoost er al.: "Infrared and Raman Spectra of LiV2O5 Single Crystal"Phys.Rev. B61. 11454-11459 (2000)
[Publications] H.Yamada and Y.Ueda: "Structural and Electric Properties of b'-CuxV2O5."J.Phys.Soc.Jpn. 69. 1437-1442 (2000)
[Publications] H.Yamada and Y.Ueda: "Charge and magnetic ordering in b-A0.33V2O5(A=Na,Ag,Li)."Physica B. 284-288. 1651-1652 (2000)
[Publications] K.Tsuda,S.Amamiya,M.Tanaka,Y.Noda,M.Isobe and Y.Ueda: "Electron Diffraction Study of the Phase Transformation of a'-NaV2O5"J.Phys.Soc.Jpn.. 69. 1935-1938 (2000)
[Publications] Yutaka Ueda: "Low-Dimensional Vanadium Oxides"J.Phys.Soc.Jpn.. Suppl.B69. 149-154 (2000)
[Publications] M.Itoh,N.Akimoto,H.Yamada,M.Isobe and Y.Ueda: "NMR Study of Charge Ordering and Magnetic Correlation in Vanadium Oxide Bronzes."J.Phys.Soc.Jpn.. Suppl.B69. 155-160 (2000)
[Publications] H.Nakao,K.Ohwada,N.Takaesue,Y.Fujii,M.Islbe,Y.Ueda et al: "X-Ray Anomalous Scattering Study of a Charge-Ordered State in VaV2O5."Phys.Rev.Lett.. 85. 4349-4352 (2000)
[Publications] M.J.Konstantinovi,Z.V.Popovi?,M.Isobe and Y.Ueda: "Raman scattering from magnetic excitations in the spin-ladder compounds CaV2O5 and MgV2O5."Phys.Rev.. B61. 15185-15188 (2000)
[Publications] Azuma M,Saito T,Hiroi Z, et al.: "New S=1/2 alternating chain compound-High pressure form of (VO)(2) P2O7-"ACTA PHYS POLA. 97. 205-208 (2000)
[Publications] Ishii K,Yamashita A,Ohishi K,HiroiZet al.: "Appearance of magnetic long-range order in the spin ladder compound La1-xSrxCuO2.5"Physica B. 289. 165-167 (2000)
[Publications] Yamada T,Hiroi Z,Takano M et al: "Spin-1/2 Heisenberg antiferromagnetic chains in the frustrated spinel lattice of GeCu2O4"J.Phys.Soc.Jpn.. 69・5. 1477-1483 (2000)
[Publications] Takeda T,Kanno R,Kawamoto Y, et al.: "Metal-semiconductor transition, charge disproportionation, and low-temperature structure of Cal-xSrxFeO3 synthesized under high-oxygen pressure"SOLID STATE SCI. 2・7. 673-687 (2000)
[Publications] Gover RKB,Kanno R,Mitchell BJ, et al.: "Effects of sintering temperature on the structure of the layered phase Li-x (Ni0.8Co0.2) O-2"J ELECTROCHEM SOC. 147・11. 4045-4051 (2000)
[Publications] Gover R,Kanno R,Mitchell B, et al.: "The effects of sintering time on the structure and electrochemical properties of Li (Ni0.8Co0.2) O-2"J POWER SOURCES. 90・1. 82-88 (2000)
[Publications] Takeda T,Kanno R,Kawamoto Y, et al.: "New cathode materials for solid oxide fuel cells-Ruthenium pyrochlores and perovskites"J ELECTROCHEM SOC. 147・5. 1730-1733 (2000)
[Publications] Kanno R,Hata T,Kawamoto Y, et al.: "Synthesis of a new lithium ionic conductor, thio-LISICON-lithium germanium sulfide system"SOLID STATE IONICS. 130・1-2. 97-104 (2000)
[Publications] Y.Ogawa,S.Koshihara,K.Koshino,T.Ogawa, et al : "Dynamical Aspects of the Photoinduced Phase Transition in Spin-Crossover Complexes"Phys.Rev.Lett.. 84・14. 3181-3184 (2000)
[Publications] Takahiro Yamada,Zenji Hiroi,Mikio Takano,Minoru Nothara et al: "Spin-1/2 Heisenberg Antiferromagnetic Chains in the Frustrated Spinel Lattice of GeCu_2O_4"J.Phys.Soc.Jpn. 69・5. 1477-1483 (2000)
[Publications] E.S.Bozin,G.H.Kwei,H.Takagi,and S.J.L.Bilinge : "Neutron Diffraction Evidence of Microscopic Charge Inhomogeneities in the CuO_2 Plane of Superconductiong La_<2-x> Sr_x CuO_4 (0【less than or equal】x【less than or equal】0.30)"Phys.Rev.Lett.. 84・25. 5856-5859 (2000)
[Publications] C.Broholm,J.F.Ditusa,C.D.Frost,T.Ito,K.Oka,R.L.Paul,H.Takagi,M.M.J.Treacv: "Holes in a Quantum Spin Liquid Guangyong Xu,G.Aeppli,M.E.Bisher"Science. 289. 419-422 (2000)
[Publications] C.Urano,M.Nohara,S.Kondo,F.Sakai,H.Taagi,T.Shiraki et al: "LiV_2O_4 Spinel as a Heavy-Mass Fermi Liquid : Anomalous Transport and Role of Geometrical Frustration"Phys.Rev.Lett.. 85・5. 1052-1055 (2000)
[Publications] M.Nohara,H.Suzuki,M.Isshiki,N.Mangkorntong,F.Sakai and H.Takagi,: "Quasiparticle Density of States of Clean and Dirty d-Wave Superconductors Mixed-State Specific Heat of La_<2-x>Sr_xCuO_4 Single Crystals"J.Phys.Soc.Jpn.. 69・6. 1602-1605 (2000)
[Publications] K.Ohishi,K.KaKuta,J.Akimitsu,W.Higemoto,R.Kadono,R.I.Miller,A.Price, et al: "Anomalous Field Dependence of the Vortex-Core Radius and Magnetic Penetration Depth in YNi_2B_2C Probed by μSR"Physica B. 289-290. 377-380 (2000)
[Publications] S.Horii,U.Mizutani,H.Ikuta,Y.Yamaka,J.H.Ye, et al: "Growth and Anisotropic Resistivity of PrBa_2Cu_4O_8 and Pr_2Ba_4Cu_7O_<15-y> Single Crystals : A Direct Probe of Metallic Cu-O Double Chains"Phys.Rev.. B61・9. 6327-6333 (2000)
[Publications] N.E.Hussey,H.T akagi,Y.Iye,S.Tajima,A.I.Rykov,and K.Yoshida: "Charge confinement on the CuO_2 planes in slightly overdoped YBa_2Cu_3O_<7-δ> and the role of metallic chains"Phys.Rev.. B61・10. R6475-R6478 (2000)
[Publications] S.Kondo,C.Urano,Y.Kurihara,M.Nohara,and H.TAKAGI: "From the Geometrically Frustrated Antiferromagnets Z_nV_2O_4 and ZnCr_2O_4 to the Heavy-Mass Fermi Liquid LiV_2O_4"J.Phys.Soc.Jpn.. 69・Suppl.B. 139-143 (2000)
[Publications] K.Waku,N.E.Hussey,F.Sakai,M.Nohara,H.Takage, et al: "The Effect of Zn-Doping on the Magnetic Field Induced Dimensional Crossover in YBa_2Cu_4O_8"J.Phys.Soc.Jpn. 69・1. 21-24 (2000)
[Publications] S.Miyasaka,H.Takagi,Y.Sekine,H.Takahashi,N.Mori et al : "Metal-Insulator Transition and Itinerant Antiferromagnetism in NiS_<2-x>Se_x Pyrite"J.Phys.Soc.Jpn. 69・10. 3166-3169 (2000)
[Publications] N.E.Hussey,S.Nakamae,K.Behnia,H.Takagi,C.Urano, et al: "Absence of Residual Quasiparticle Conductivity in the Underdoped Cuprate YBa_2Cu_4O_8"Phys.Rev.Lett. 85・19. 4140-4143 (2000)
[Publications] T.Yokoya,T.Kiss,T.Watanabe,S.Shin,M.Nohara,H.Takagi,and T.Oguchi: "Ultrahigh-Resolution Photoemission Spectroscopy of Ni Borocarbides : Direct Observatio of the Superconducting Gap and a Change in Gap Anisotropy by Impurity"Phys.Rev.Lett.. 85・23. 4952-4955 (2000)

2000 Fiscal Year Annual Research Report

量子フラストレーション系の物質探索・創製

Principal Investigator

高木 英典 東京大学, 大学院・新領域創成科学研究科, 教授 (40187935)

Research Products

[Publications] K.Ohwaka H.Nakao,H.Nakatogawa,N.Takesue et al.: "Pressure-Induced Phase Transition in NaV2O5 at Low Temperature"J.Phys.Soc.Jpn.. 69. 639-642 (2000)

[Publications] M.Itoh,N.Akimoto,M.Tsuchiya,H.Yamada,M.Isobe and Y.Ueda: "51V NMR study of charge ordering in AV6O15(A=Ca,Na andAg)."Physica B. 281-282. 606-607 (2000)

[Publications] Z.V.Popvic,R.Gajic,M.J.Konstantinovic,R.Provoost er al.: "Infrared and Raman Spectra of LiV2O5 Single Crystal"Phys.Rev. B61. 11454-11459 (2000)

[Publications] H.Yamada and Y.Ueda: "Structural and Electric Properties of b'-CuxV2O5."J.Phys.Soc.Jpn. 69. 1437-1442 (2000)

[Publications] H.Yamada and Y.Ueda: "Charge and magnetic ordering in b-A0.33V2O5(A=Na,Ag,Li)."Physica B. 284-288. 1651-1652 (2000)

[Publications] K.Tsuda,S.Amamiya,M.Tanaka,Y.Noda,M.Isobe and Y.Ueda: "Electron Diffraction Study of the Phase Transformation of a'-NaV2O5"J.Phys.Soc.Jpn.. 69. 1935-1938 (2000)

[Publications] Yutaka Ueda: "Low-Dimensional Vanadium Oxides"J.Phys.Soc.Jpn.. Suppl.B69. 149-154 (2000)

[Publications] M.Itoh,N.Akimoto,H.Yamada,M.Isobe and Y.Ueda: "NMR Study of Charge Ordering and Magnetic Correlation in Vanadium Oxide Bronzes."J.Phys.Soc.Jpn.. Suppl.B69. 155-160 (2000)

[Publications] H.Nakao,K.Ohwada,N.Takaesue,Y.Fujii,M.Islbe,Y.Ueda et al: "X-Ray Anomalous Scattering Study of a Charge-Ordered State in VaV2O5."Phys.Rev.Lett.. 85. 4349-4352 (2000)

[Publications] M.J.Konstantinovi,Z.V.Popovi?,M.Isobe and Y.Ueda: "Raman scattering from magnetic excitations in the spin-ladder compounds CaV2O5 and MgV2O5."Phys.Rev.. B61. 15185-15188 (2000)

[Publications] Azuma M,Saito T,Hiroi Z, et al.: "New S=1/2 alternating chain compound-High pressure form of (VO)(2) P2O7-"ACTA PHYS POLA. 97. 205-208 (2000)

[Publications] Ishii K,Yamashita A,Ohishi K,HiroiZet al.: "Appearance of magnetic long-range order in the spin ladder compound La1-xSrxCuO2.5"Physica B. 289. 165-167 (2000)

[Publications] Yamada T,Hiroi Z,Takano M et al: "Spin-1/2 Heisenberg antiferromagnetic chains in the frustrated spinel lattice of GeCu2O4"J.Phys.Soc.Jpn.. 69・5. 1477-1483 (2000)

[Publications] Takeda T,Kanno R,Kawamoto Y, et al.: "Metal-semiconductor transition, charge disproportionation, and low-temperature structure of Cal-xSrxFeO3 synthesized under high-oxygen pressure"SOLID STATE SCI. 2・7. 673-687 (2000)

[Publications] Gover RKB,Kanno R,Mitchell BJ, et al.: "Effects of sintering temperature on the structure of the layered phase Li-x (Ni0.8Co0.2) O-2"J ELECTROCHEM SOC. 147・11. 4045-4051 (2000)

[Publications] Gover R,Kanno R,Mitchell B, et al.: "The effects of sintering time on the structure and electrochemical properties of Li (Ni0.8Co0.2) O-2"J POWER SOURCES. 90・1. 82-88 (2000)

[Publications] Takeda T,Kanno R,Kawamoto Y, et al.: "New cathode materials for solid oxide fuel cells-Ruthenium pyrochlores and perovskites"J ELECTROCHEM SOC. 147・5. 1730-1733 (2000)

[Publications] Kanno R,Hata T,Kawamoto Y, et al.: "Synthesis of a new lithium ionic conductor, thio-LISICON-lithium germanium sulfide system"SOLID STATE IONICS. 130・1-2. 97-104 (2000)

[Publications] Y.Ogawa,S.Koshihara,K.Koshino,T.Ogawa, et al : "Dynamical Aspects of the Photoinduced Phase Transition in Spin-Crossover Complexes"Phys.Rev.Lett.. 84・14. 3181-3184 (2000)

[Publications] Takahiro Yamada,Zenji Hiroi,Mikio Takano,Minoru Nothara et al: "Spin-1/2 Heisenberg Antiferromagnetic Chains in the Frustrated Spinel Lattice of GeCu_2O_4"J.Phys.Soc.Jpn. 69・5. 1477-1483 (2000)

[Publications] E.S.Bozin,G.H.Kwei,H.Takagi,and S.J.L.Bilinge : "Neutron Diffraction Evidence of Microscopic Charge Inhomogeneities in the CuO_2 Plane of Superconductiong La_<2-x> Sr_x CuO_4 (0【less than or equal】x【less than or equal】0.30)"Phys.Rev.Lett.. 84・25. 5856-5859 (2000)

[Publications] C.Broholm,J.F.Ditusa,C.D.Frost,T.Ito,K.Oka,R.L.Paul,H.Takagi,M.M.J.Treacv: "Holes in a Quantum Spin Liquid Guangyong Xu,G.Aeppli,M.E.Bisher"Science. 289. 419-422 (2000)

[Publications] C.Urano,M.Nohara,S.Kondo,F.Sakai,H.Taagi,T.Shiraki et al: "LiV_2O_4 Spinel as a Heavy-Mass Fermi Liquid : Anomalous Transport and Role of Geometrical Frustration"Phys.Rev.Lett.. 85・5. 1052-1055 (2000)

[Publications] M.Nohara,H.Suzuki,M.Isshiki,N.Mangkorntong,F.Sakai and H.Takagi,: "Quasiparticle Density of States of Clean and Dirty d-Wave Superconductors Mixed-State Specific Heat of La_<2-x>Sr_xCuO_4 Single Crystals"J.Phys.Soc.Jpn.. 69・6. 1602-1605 (2000)

[Publications] K.Ohishi,K.KaKuta,J.Akimitsu,W.Higemoto,R.Kadono,R.I.Miller,A.Price, et al: "Anomalous Field Dependence of the Vortex-Core Radius and Magnetic Penetration Depth in YNi_2B_2C Probed by μSR"Physica B. 289-290. 377-380 (2000)

[Publications] S.Horii,U.Mizutani,H.Ikuta,Y.Yamaka,J.H.Ye, et al: "Growth and Anisotropic Resistivity of PrBa_2Cu_4O_8 and Pr_2Ba_4Cu_7O_<15-y> Single Crystals : A Direct Probe of Metallic Cu-O Double Chains"Phys.Rev.. B61・9. 6327-6333 (2000)

[Publications] N.E.Hussey,H.T akagi,Y.Iye,S.Tajima,A.I.Rykov,and K.Yoshida: "Charge confinement on the CuO_2 planes in slightly overdoped YBa_2Cu_3O_<7-δ> and the role of metallic chains"Phys.Rev.. B61・10. R6475-R6478 (2000)

[Publications] S.Kondo,C.Urano,Y.Kurihara,M.Nohara,and H.TAKAGI: "From the Geometrically Frustrated Antiferromagnets Z_nV_2O_4 and ZnCr_2O_4 to the Heavy-Mass Fermi Liquid LiV_2O_4"J.Phys.Soc.Jpn.. 69・Suppl.B. 139-143 (2000)

[Publications] K.Waku,N.E.Hussey,F.Sakai,M.Nohara,H.Takage, et al: "The Effect of Zn-Doping on the Magnetic Field Induced Dimensional Crossover in YBa_2Cu_4O_8"J.Phys.Soc.Jpn. 69・1. 21-24 (2000)

[Publications] S.Miyasaka,H.Takagi,Y.Sekine,H.Takahashi,N.Mori et al : "Metal-Insulator Transition and Itinerant Antiferromagnetism in NiS_<2-x>Se_x Pyrite"J.Phys.Soc.Jpn. 69・10. 3166-3169 (2000)

[Publications] N.E.Hussey,S.Nakamae,K.Behnia,H.Takagi,C.Urano, et al: "Absence of Residual Quasiparticle Conductivity in the Underdoped Cuprate YBa_2Cu_4O_8"Phys.Rev.Lett. 85・19. 4140-4143 (2000)

[Publications] T.Yokoya,T.Kiss,T.Watanabe,S.Shin,M.Nohara,H.Takagi,and T.Oguchi: "Ultrahigh-Resolution Photoemission Spectroscopy of Ni Borocarbides : Direct Observatio of the Superconducting Gap and a Change in Gap Anisotropy by Impurity"Phys.Rev.Lett.. 85・23. 4952-4955 (2000)

高木英典東京大学, 大学院・新領域創成科学研究科, 教授 (40187935)