2000 Fiscal Year Annual Research Report

低次元銅酸化物における電荷とスピンの長距離秩序の研究(超伝導発現機構との関わり)

Research Project

Project/Area Number	10440098
Research Institution	Tohoku University
Principal Investigator	小池洋二東北大学, 大学院・工学研究科, 教授 (70134038)
Co-Investigator(Kenkyū-buntansha)	加藤雅恒東北大学, 大学院・工学研究科, 助教授 (50211850) 野地尚東北大学, 大学院・工学研究科, 助手 (50180740)
Keywords	高温超伝導 / ストライプ秩序 / μSR / 中性子散乱 / 輸送特性 / 単結晶育成 / 1 / 8異常
Research Abstract	1.これまで誰も成功していなかったLa系高温超伝導体La_<2-x>Ba_xCuO_4(LBCO)のx=1/8付近(正確にはx=0.11)の大型単結晶の育成に成功した。輸送特性を測定した結果、60K以下の低温で、La_<1.6-x>Nd_<0.4>Sr_xCuO_4のx=1/8の単結晶で見られているような電気抵抗とホール効果の異常な振る舞いを観測し、LBCOのx=1/8においても、電荷とスピンの静的なストライプ秩序が形成されている可能性が極めて高いことが分かった。ストライプ秩序を確証するために、現在、中性子散乱実験を計画中である。 2.昨年度発見したLa_<2-x>Sr_xCu_<1-y>Zn_yO_4単結晶のx=0.21における超伝導の異常な抑制について、μSRと中性子散乱の実験を行った。その結果、μSRからは、低温において、x=0.21で周りの組成の試料に比べて特異的に磁気相関が発達していることが分かった。また、その磁気相関は、1%のZn置換によって著しく発達することも分かった。中性子弾性散乱からは、超伝導が最も抑制されているx=0.21,y=0.01の試料において、20K以下で、x=1/8で観測されているような(π,π)周りの非整合磁気ピークを観測した。したがって、x=0.21においても、x=1/8と同様に、電荷とスピンの動的なストライプ相関が静的に安定化する傾向にあり、1%置換されたZnによってピン止めされて、静的なストライプ秩序が形成されたものと思われる。 3.3年間の研究で、Cuあたりのホール濃度が1/8で超伝導が抑制される所謂1/8異常が、Bi系やY系においても観測されたことから、1/8異常がLa系に特有の現象ではなく、CuO_2面をもつ高温超伝導体に共通の性質であることが分かった。また、La系のx=0.21でもx=1/8と同様の現象が発見された。以上のことから、電荷とスピンの動的なストライプ相関(ストライプゆらぎ)はCuO_2面を持つ高温超伝導体に共通に、超伝導が発現する広いホール濃度範囲で存在し、それが高温超伝導の発現に効いている可能性があると結論できた。

Research Products
(31 results)

All Other

All Publications (31 results)

[Publications] M.Akoshima: "On the 60K Plateau of T_c in Y_<1-x>Ca_xBa_2Cu_3O_<7-S> in Relation to the 1/8 Problem"Journal of the Physical Society of Japan. 67・10. 3653-3654 (1998)
[Publications] N.Kakinuma: "Anomalies of T_c, resistivity, and thermoelectric power in the overdoped region of La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Physical Review B. 59・2. 1491-1496 (1999)
[Publications] I.Watanabe: "μSR Study on the Magnetic State of the Zn-Substituted Bi-2212 System "Physica B. 259-261. 557-558 (1999)
[Publications] N.L.Saini: "Local structure and T_c suppression at 1/8 doping in Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2 O_<8+d> superconductor"Journal of Synchrotron Radiation. 6. 752-754 (1999)
[Publications] I.Watanabe: "Anomalous slowing down of Cu-spin fluctuations observed by muon spin relaxation in the Zn-substituted Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> System around the hole concentration of 1/8 per Cu"Physical Review B. 60・14. R9955-R9958 (1999)
[Publications] Y.Koike: "1/8 Problems in the La-,Bi- and Y-Based Cuprates and New Anomalies in the Overdoped Region of the La-Based Cuprate"International Journal of Modern Physics B. 13・29,30 & 31. 3546-3551 (1999)
[Publications] I.Watanabe: "μ^+SR Study on Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> around the Hole Concentration of 1/8 per Cu"Journal of Low Temperature Physics. 117・3/4. 503-507 (1999)
[Publications] M.Akoshima: "Transport and μSR studies at p〜1/8 in the Bi-2212 and Y-123 phases"Journal of Low Temperature Physics. 117・5/6. 1163-1167 (1999)
[Publications] Y.Koike: "Transport and T_c Anomalies around x=0.22 in La_<2-x>Sr_xCu_<1-y>MyO_4 (M=Zn, Ga, Ni) : Possibility of Change and/or Spin Ordering"Journal of Low Temperature Physics. 117・5/6. 1157-1161 (1999)
[Publications] T.Adachi: "Transport anomalies in the Zn-substituted La_<2-x>Sr_xCu_<1-y>Zn_yO_4 with X〜0.115; Possibility of the pinning of CDW and SDW by Zn"Journal of Low Temperature Physics. 117・5/6. 1151-1155 (1999)
[Publications] K.Kudo: "Spin gap and hole pairing of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La) single crystals studied by the electrical resistivity and thermal conductivity"Journal of Low Temperature Physics. 117・5/6. 1689-1693 (1999)
[Publications] I.Watanabe: "μSR Study on the "1/8 Effect" in the Zn-substituted Bi-2212 System"Physica B. 284-288. 1071-1072 (2000)
[Publications] 長井一郎: "Sr_<14-x>Ca_xCu_<24>O_<41>のラマン散乱"粉体および粉末冶金. 46・9. 1004-1008 (1999)
[Publications] K.Kudo: "Electrical resistivity of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca,La) single crystals : Localization of hole pairs in the ladder"Physica B. 284-288. 651-652 (2000)
[Publications] T.Adachi: "Nonlinear conduction in La_<2-x>Ba_xCuO_4"Physica B. 284-288. 655-656 (2000)
[Publications] I.Watanabe: "Muon-spin-relaxation study on the Cu-spin state of Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> around the hole concentration of 1/8 per Cu"Physical Review B. 62・21. 14524-14530 (2000)
[Publications] M.Osada: "Raman-active phonons and their doping dependence in spin-ladder Sr_<14>Cu_<24>O_<41>"Physica C. 338・1 & 2. 161-165 (2000)
[Publications] M.Osada: "Charge and spin dynamics in spin-ladder Sr_<14>Cu_<24>O_<41> investigated by Raman scattering"Advances in Superconductivity XII. 188-190 (2000)
[Publications] K.Kudo: "Spin gap of Sr_<14-x>A_xCu_<24-y>M_yO_<41>(A=Ca, La : M=Zn, Ni) studied by thermal conductivity"Journal of Physics and Chemistry of Solids. 62・1-2. 361-364 (2001)
[Publications] Y.Koike: "Impurity Effects on the stripes in the La-214, Bi-2212 and Y-123 Phases"AIP Conference Proceedings. (印刷中).
[Publications] Y.Koike: "Possible charge and/or spin ordering in the Bi-2212, Y-123 and La-214 phases"International Journal of Modern Physics B. (印刷中).
[Publications] I.Watanabe: "μSR study on the Cu-spin state in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"International Journal of Modern Physics B. (印刷中).
[Publications] Y.Koike: "Cu-site-substitution effects on the 1/8 anomaly in the high-T_ccuprates and on the anomaly at x=0.21 in La_<2-x>Sr_xCuO_4"Physica C. (印刷中).
[Publications] H.Kimura: "Neutron-Scattering Study of Incommensurate Elastic Magnetic Peaks in La_<2-x>Sr_xCu_<1-y>Zn_yO_4 (x〜0.21, y〜0.01)"Journal of the Physical Society of Japan. (印刷中).
[Publications] I.Watanabe: "μ^+SR study on hole-doped high-T_c oxides around the hole concentration of 1/8 per Cu"Physica B. 289-290. 351-354 (2000)
[Publications] M.Akoshima : "Anomalous muon-spin relaxation in the Zn-substituted YBa_2Cu_<3-2y>Zn_<2y>O_<7-δ> around the hole concentration of 1/8 per Cu"Physical Review B. 62・10. 6761-6765 (2000)
[Publications] Y.Koike: "1/8 anomaly in the Bi-2212 and Y-123 phases"Physica C. 314-318. 1751-1754 (2000)
[Publications] T.Kawamata: "Giant suppression of superconductivity at x=0.21 in the Zn-substituted La_<2-x>Sr_xCu_<1-y>Zn_yO_4 single crystals"Physical Review B. 62・18. R11981-R11984 (2000)
[Publications] I.Watanabe: "Possibility of an ordered state of spins and holes in single-crystal La_<2-x>Sr_xCu_<1-y>Zn_yO_4 (x=0.21, y=0 and 0.01) studied by MSR"Physical Review B. 62・18. R11985-R11988 (2000)
[Publications] K.Kudo: "Spin Gap and Hole Pairing in the Spin-Ladder Cuprate Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La) Studied by the Thermal Conductivity (印刷中)"Journal of the Physical Society of Japan. 70・2. (2001)
[Publications] Y.Koike: "Possible stripe ordering at x=0.21 in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Physica C. (印刷中).

2000 Fiscal Year Annual Research Report

低次元銅酸化物における電荷とスピンの長距離秩序の研究(超伝導発現機構との関わり)

Principal Investigator

小池 洋二 東北大学, 大学院・工学研究科, 教授 (70134038)

Research Products

[Publications] M.Akoshima: "On the 60K Plateau of T_c in Y_<1-x>Ca_xBa_2Cu_3O_<7-S> in Relation to the 1/8 Problem"Journal of the Physical Society of Japan. 67・10. 3653-3654 (1998)

[Publications] N.Kakinuma: "Anomalies of T_c, resistivity, and thermoelectric power in the overdoped region of La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Physical Review B. 59・2. 1491-1496 (1999)

[Publications] I.Watanabe: "μSR Study on the Magnetic State of the Zn-Substituted Bi-2212 System "Physica B. 259-261. 557-558 (1999)

[Publications] N.L.Saini: "Local structure and T_c suppression at 1/8 doping in Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2 O_<8+d> superconductor"Journal of Synchrotron Radiation. 6. 752-754 (1999)

[Publications] I.Watanabe: "Anomalous slowing down of Cu-spin fluctuations observed by muon spin relaxation in the Zn-substituted Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> System around the hole concentration of 1/8 per Cu"Physical Review B. 60・14. R9955-R9958 (1999)

[Publications] Y.Koike: "1/8 Problems in the La-,Bi- and Y-Based Cuprates and New Anomalies in the Overdoped Region of the La-Based Cuprate"International Journal of Modern Physics B. 13・29,30 & 31. 3546-3551 (1999)

[Publications] I.Watanabe: "μ^+SR Study on Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> around the Hole Concentration of 1/8 per Cu"Journal of Low Temperature Physics. 117・3/4. 503-507 (1999)

[Publications] M.Akoshima: "Transport and μSR studies at p〜1/8 in the Bi-2212 and Y-123 phases"Journal of Low Temperature Physics. 117・5/6. 1163-1167 (1999)

[Publications] Y.Koike: "Transport and T_c Anomalies around x=0.22 in La_<2-x>Sr_xCu_<1-y>MyO_4 (M=Zn, Ga, Ni) : Possibility of Change and/or Spin Ordering"Journal of Low Temperature Physics. 117・5/6. 1157-1161 (1999)

[Publications] T.Adachi: "Transport anomalies in the Zn-substituted La_<2-x>Sr_xCu_<1-y>Zn_yO_4 with X〜0.115; Possibility of the pinning of CDW and SDW by Zn"Journal of Low Temperature Physics. 117・5/6. 1151-1155 (1999)

[Publications] K.Kudo: "Spin gap and hole pairing of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La) single crystals studied by the electrical resistivity and thermal conductivity"Journal of Low Temperature Physics. 117・5/6. 1689-1693 (1999)

[Publications] I.Watanabe: "μSR Study on the "1/8 Effect" in the Zn-substituted Bi-2212 System"Physica B. 284-288. 1071-1072 (2000)

[Publications] 長井一郎: "Sr_<14-x>Ca_xCu_<24>O_<41>のラマン散乱"粉体および粉末冶金. 46・9. 1004-1008 (1999)

[Publications] K.Kudo: "Electrical resistivity of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca,La) single crystals : Localization of hole pairs in the ladder"Physica B. 284-288. 651-652 (2000)

[Publications] T.Adachi: "Nonlinear conduction in La_<2-x>Ba_xCuO_4"Physica B. 284-288. 655-656 (2000)

[Publications] I.Watanabe: "Muon-spin-relaxation study on the Cu-spin state of Bi_2Sr_2Ca_<1-x>Y_x(Cu_<1-y>Zn_y)_2O_<8+δ> around the hole concentration of 1/8 per Cu"Physical Review B. 62・21. 14524-14530 (2000)

[Publications] M.Osada: "Raman-active phonons and their doping dependence in spin-ladder Sr_<14>Cu_<24>O_<41>"Physica C. 338・1 & 2. 161-165 (2000)

[Publications] M.Osada: "Charge and spin dynamics in spin-ladder Sr_<14>Cu_<24>O_<41> investigated by Raman scattering"Advances in Superconductivity XII. 188-190 (2000)

[Publications] K.Kudo: "Spin gap of Sr_<14-x>A_xCu_<24-y>M_yO_<41>(A=Ca, La : M=Zn, Ni) studied by thermal conductivity"Journal of Physics and Chemistry of Solids. 62・1-2. 361-364 (2001)

[Publications] Y.Koike: "Impurity Effects on the stripes in the La-214, Bi-2212 and Y-123 Phases"AIP Conference Proceedings. (印刷中).

[Publications] Y.Koike: "Possible charge and/or spin ordering in the Bi-2212, Y-123 and La-214 phases"International Journal of Modern Physics B. (印刷中).

[Publications] I.Watanabe: "μSR study on the Cu-spin state in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"International Journal of Modern Physics B. (印刷中).

[Publications] Y.Koike: "Cu-site-substitution effects on the 1/8 anomaly in the high-T_ccuprates and on the anomaly at x=0.21 in La_<2-x>Sr_xCuO_4"Physica C. (印刷中).

[Publications] H.Kimura: "Neutron-Scattering Study of Incommensurate Elastic Magnetic Peaks in La_<2-x>Sr_xCu_<1-y>Zn_yO_4 (x〜0.21, y〜0.01)"Journal of the Physical Society of Japan. (印刷中).

[Publications] I.Watanabe: "μ^+SR study on hole-doped high-T_c oxides around the hole concentration of 1/8 per Cu"Physica B. 289-290. 351-354 (2000)

[Publications] M.Akoshima : "Anomalous muon-spin relaxation in the Zn-substituted YBa_2Cu_<3-2y>Zn_<2y>O_<7-δ> around the hole concentration of 1/8 per Cu"Physical Review B. 62・10. 6761-6765 (2000)

[Publications] Y.Koike: "1/8 anomaly in the Bi-2212 and Y-123 phases"Physica C. 314-318. 1751-1754 (2000)

[Publications] T.Kawamata: "Giant suppression of superconductivity at x=0.21 in the Zn-substituted La_<2-x>Sr_xCu_<1-y>Zn_yO_4 single crystals"Physical Review B. 62・18. R11981-R11984 (2000)

[Publications] I.Watanabe: "Possibility of an ordered state of spins and holes in single-crystal La_<2-x>Sr_xCu_<1-y>Zn_yO_4 (x=0.21, y=0 and 0.01) studied by MSR"Physical Review B. 62・18. R11985-R11988 (2000)

[Publications] K.Kudo: "Spin Gap and Hole Pairing in the Spin-Ladder Cuprate Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La) Studied by the Thermal Conductivity (印刷中)"Journal of the Physical Society of Japan. 70・2. (2001)

[Publications] Y.Koike: "Possible stripe ordering at x=0.21 in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Physica C. (印刷中).

小池洋二東北大学, 大学院・工学研究科, 教授 (70134038)