1992 Fiscal Year Annual Research Report

酸化物高温超伝導体における層状構造の効果

Research Project

Project/Area Number	03640328
Research Institution	Tohoku University
Principal Investigator	立木昌東北大学, 金属材料研究所, 教授 (20028111)
Co-Investigator(Kenkyū-buntansha)	高橋三郎東北大学, 金属材料研究所, 助手 (60171485) 小山富男東北大学, 金属材料研究所, 助手 (30153696) 松本秀樹東北大学, 金属材料研究所, 助教授 (40209648)
Keywords	酸化物高温超伝導体 / 層状超伝導体 / 混合状態 / 多層膜超伝導体 / 磁化過程 / 近接効果
Research Abstract	本年度は、昨年度の研究実績を踏まえて、酸化物高温超伝導体に対する層状構造の効果をさらに調べた。本年度の研究実績は以下のとおりである。酸化物超伝導体の混合状態の性質には、層状構造にともなう超伝導秩序の不均一性に起因して、従来の第2種超伝導体には見られない新しい効果が現れることを明らかにした。特に、層に平行方向の渦糸と輸送電流との相互作用に対して、従来の理論で無視されている輸送電流の空間分布の非一様性が本質的に重要となる事を示した。この効果により、渦糸に作用する実効的なローレンツ力の大きさは従来の理論による評価と大きく異なる可能性がある。このため、酸化物高温超伝導体の混合状態におけるピニング力や臨界電流を評価するためには、層状構造を積極的に考慮したモデルを用いなければならない事を明らかにした。酸化物超伝導体の上部臨界磁場は層状構造に起因して大きな異方性を示すが、その角度依存性の計算はこれまで行われていなかった。本研究で層状構造を積極的に取り入れた層状超伝導体に対する現象論的ギンツブルグ-ランダウ理論を構築し、上部臨界磁場の角度変化を計算した。上部臨界磁場の角度変化の特徴は、層状構造に起因する次元クロスオーバーと近接効果により良く理解できる事を明らかにした。酸化物超伝導体の抵抗状態に対する現象論を発展させ、電気抵抗の磁場依存性を計算した。酸化物超伝導体の抵抗状態の挙動は、熱活性型のフラックス流から単純なフラックス流へのクロスオーバーとして理解できることを示した。酸化物超伝導体の電子状態に対する理解を深めるために、強結合電子系に対する複合演算子の方法を発展させてスピンと電荷の揺らぎのホール依存性を計算した。

Research Products
(29 results)

All Other

All Publications (29 results)

[Publications] Y.Fukuda: "Electronic states of core levels and valence bands for KxC_<60> studied by x-ray photoelectron spectroscopy" Physica C. 181. 320-324 (1991)
[Publications] M.Tachiki: "Properties of flux lines in cuprate oxide superconductors" Physica C. 185-189. 303-308 (1991)
[Publications] K.Petersen: "Evidence from heat conductivity for normal-conducting chains in the hihg Tc superconductor YBa_2Cu_3O_<6.9>" Physica C. 185-189. 1363-1364 (1991)
[Publications] N.Sanada: "Effects of oxygen loss from Bi-2201 phase doped by Pb and La on superconductivity" Physica C. 185-189. 665-666 (1991)
[Publications] M.Nagoshi: "Photoemission study on Ba_<1-X>K_XBi_<1-X>O_<3-δ> and Bi_<1-X>O_<3-δ>" Physica C. 185-189. 1051-1052 (1991)
[Publications] Y.Fukuda: "Effects of substitution for Fe and Co for Cu in Bi_2Sr_<1.8>Ca_<1.2>Cu_2O_y on electronic state studied by photoemission" Physica C. 190. 73-74 (1991)
[Publications] S.Takahashi: "Optical conductivity in the superocnducting state of layered cuprate oxides" Physica C. 185-189. 1677-1678 (1991)
[Publications] M.Tachiki: "Knight shift and nuclear relaxation rate in layered cuprate superconductors" Physica C. 185-189. 1661-1662 (1991)
[Publications] M.Sasaki: "Study of the midgap state in oxide superconductors by composite operator approach" Physica C. 185-189. 1491-1492 (1991)
[Publications] T.Koyama: "Mixed state in layered superconductors" Physica C. 185-189. 1597-1598 (1991)
[Publications] H.Matsumoto: "Composite electronic excitations in high Tc oxide superconductors" JJAP Series,Mechanisms of superconductivity(JJAP). 7. 324-329 (1992)
[Publications] H.Matsumoto: "Highly correlated electron state in oxide superconductors" Prog.Theor.Phys.Suppl.106. 31-42 (1991)
[Publications] M.Tachiki: "Proximity effects in high-Tc oxide superconductors" Physica C. 191. 363-370 (1992)
[Publications] M.Tachiki: "Electronic state in oxide superconductors" Springer series in solid-state science (Springer-Verlag,Berlin). 106. 55-62 (1992)
[Publications] T.Koyama: "Theory for resitive transition in cuprate oxides multilayers" Physica C. 193. 163-170 (1992)
[Publications] M.Nagoshi: "Electronic staes of BaBiO_<3-δ> and k-doping effects studied by photoemission spectroscopy" J.Phys.Condens.Matter. 4. 5679-5781 (1992)
[Publications] M.Nagoshi: "Changes of electronic states of superconducting oxides by various surface treatments studied by XPS and SEM" Proc.of 4th International Symposium on Superconductivity(ISS'91). 79-82 (1992)
[Publications] M.Tachiki: "Superconducting properties of layered cuprate oxides" Prog.Theor.Phys.Suppl.108. 297-311 (1992)
[Publications] T.Koyama: "New continuous model for intrinsic layered superconductors" Physica C. 194. 20-30 (1992)
[Publications] H.Matsumoto: "Composite-operator approach for the p-d mixing model of oxide superconductors" Phys.Rev.B. 46. 3009-3021 (1992)
[Publications] M.Sasaki: "Electronic state of high-Tc cuprate superconductors as studied by the use of the composite-operator approach" Phys.Rev.B. 46. 3022-3040 (1992)
[Publications] C.D.Bredl: "Anisotropic low-temperature heat transport in YBa_2Cu_3O_<6.9> single crystal" Z.Phys.B-Condensed Matter. 86. 187-191 (1992)
[Publications] H.Matsumoto: "Spin and charge fluctuation and electronic state in high Tc superconductors" J.Phys.Chem.Solids. 53. 1507-1514 (1992)
[Publications] Y.Fukuda: "Photoemission study of iodine-intercalated Bi_2Sr_2CaCu_2O_y single crystal" J.Phys.Chem.Solids. 53. 1589-1594 (1992)
[Publications] M.Tachiki: "Effect of intrinsic pinning on critical current in cuprate superconductors" Cryogenics. 32. 923-930 (1992)
[Publications] S.Ishihara: "Dynamical spin and charge fluctuations in the p-d mixing model" Physica B.
[Publications] X.G.Qiu: "Resitive dissipation in the flux liquid state in high temperature superconductors" Physica C.
[Publications] M.Tachiki: "Driving and pinning forces acting on vortices in layered superconductors" Phys.Rev.B.
[Publications] N.Takezawa: "Angular dependence of the upper critical field in layered superconductors" Physica C.

1992 Fiscal Year Annual Research Report

酸化物高温超伝導体における層状構造の効果

Principal Investigator

立木 昌 東北大学, 金属材料研究所, 教授 (20028111)

Research Products

[Publications] Y.Fukuda: "Electronic states of core levels and valence bands for KxC_<60> studied by x-ray photoelectron spectroscopy" Physica C. 181. 320-324 (1991)

[Publications] M.Tachiki: "Properties of flux lines in cuprate oxide superconductors" Physica C. 185-189. 303-308 (1991)

[Publications] K.Petersen: "Evidence from heat conductivity for normal-conducting chains in the hihg Tc superconductor YBa_2Cu_3O_<6.9>" Physica C. 185-189. 1363-1364 (1991)

[Publications] N.Sanada: "Effects of oxygen loss from Bi-2201 phase doped by Pb and La on superconductivity" Physica C. 185-189. 665-666 (1991)

[Publications] M.Nagoshi: "Photoemission study on Ba_<1-X>K_XBi_<1-X>O_<3-δ> and Bi_<1-X>O_<3-δ>" Physica C. 185-189. 1051-1052 (1991)

[Publications] Y.Fukuda: "Effects of substitution for Fe and Co for Cu in Bi_2Sr_<1.8>Ca_<1.2>Cu_2O_y on electronic state studied by photoemission" Physica C. 190. 73-74 (1991)

[Publications] S.Takahashi: "Optical conductivity in the superocnducting state of layered cuprate oxides" Physica C. 185-189. 1677-1678 (1991)

[Publications] M.Tachiki: "Knight shift and nuclear relaxation rate in layered cuprate superconductors" Physica C. 185-189. 1661-1662 (1991)

[Publications] M.Sasaki: "Study of the midgap state in oxide superconductors by composite operator approach" Physica C. 185-189. 1491-1492 (1991)

[Publications] T.Koyama: "Mixed state in layered superconductors" Physica C. 185-189. 1597-1598 (1991)

[Publications] H.Matsumoto: "Composite electronic excitations in high Tc oxide superconductors" JJAP Series,Mechanisms of superconductivity(JJAP). 7. 324-329 (1992)

[Publications] H.Matsumoto: "Highly correlated electron state in oxide superconductors" Prog.Theor.Phys.Suppl.106. 31-42 (1991)

[Publications] M.Tachiki: "Proximity effects in high-Tc oxide superconductors" Physica C. 191. 363-370 (1992)

[Publications] M.Tachiki: "Electronic state in oxide superconductors" Springer series in solid-state science (Springer-Verlag,Berlin). 106. 55-62 (1992)

[Publications] T.Koyama: "Theory for resitive transition in cuprate oxides multilayers" Physica C. 193. 163-170 (1992)

[Publications] M.Nagoshi: "Electronic staes of BaBiO_<3-δ> and k-doping effects studied by photoemission spectroscopy" J.Phys.Condens.Matter. 4. 5679-5781 (1992)

[Publications] M.Nagoshi: "Changes of electronic states of superconducting oxides by various surface treatments studied by XPS and SEM" Proc.of 4th International Symposium on Superconductivity(ISS'91). 79-82 (1992)

[Publications] M.Tachiki: "Superconducting properties of layered cuprate oxides" Prog.Theor.Phys.Suppl.108. 297-311 (1992)

[Publications] T.Koyama: "New continuous model for intrinsic layered superconductors" Physica C. 194. 20-30 (1992)

[Publications] H.Matsumoto: "Composite-operator approach for the p-d mixing model of oxide superconductors" Phys.Rev.B. 46. 3009-3021 (1992)

[Publications] M.Sasaki: "Electronic state of high-Tc cuprate superconductors as studied by the use of the composite-operator approach" Phys.Rev.B. 46. 3022-3040 (1992)

[Publications] C.D.Bredl: "Anisotropic low-temperature heat transport in YBa_2Cu_3O_<6.9> single crystal" Z.Phys.B-Condensed Matter. 86. 187-191 (1992)

[Publications] H.Matsumoto: "Spin and charge fluctuation and electronic state in high Tc superconductors" J.Phys.Chem.Solids. 53. 1507-1514 (1992)

[Publications] Y.Fukuda: "Photoemission study of iodine-intercalated Bi_2Sr_2CaCu_2O_y single crystal" J.Phys.Chem.Solids. 53. 1589-1594 (1992)

[Publications] M.Tachiki: "Effect of intrinsic pinning on critical current in cuprate superconductors" Cryogenics. 32. 923-930 (1992)

[Publications] S.Ishihara: "Dynamical spin and charge fluctuations in the p-d mixing model" Physica B.

[Publications] X.G.Qiu: "Resitive dissipation in the flux liquid state in high temperature superconductors" Physica C.

[Publications] M.Tachiki: "Driving and pinning forces acting on vortices in layered superconductors" Phys.Rev.B.

[Publications] N.Takezawa: "Angular dependence of the upper critical field in layered superconductors" Physica C.

立木昌東北大学, 金属材料研究所, 教授 (20028111)