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ビスマス系・イットリウム系銅酸化物および梯子型銅酸化物における電荷とスピンの秩序

Research Project

Project/Area Number 12046210
Research Category

Grant-in-Aid for Scientific Research on Priority Areas (A)

Allocation TypeSingle-year Grants
Review Section Science and Engineering
Research InstitutionTohoku 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) 野地 尚  東北大学, 大学院・工学研究科, 助手 (50180740)
Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords高温超伝導 / ストライプ秩序 / MSR / NMR / ホール係数 / 1 / 8異常 / 熱伝導 / スピンギャップ / μSR / 中性子散乱 / 梯子型酸化物 / 単結晶育成
Research Abstract

1.Y系高温超電導体YBa_2Cu_<3-2y>Zn_<2y>O_<7-δ>のNMMR実験を行い、Znで部分置換(y=0.025)したP(CuO_2面のCuあたりのホール濃度)〜1/8の試料では、NMR信号のワイプアウト現象が顕著になることを発見した。p〜1/8で、電荷とスピンの動的なストライプ秩序がZnによってピン止めされる傾向が顕著になったものと理解できる。
2.酸素の相分離を抑制した過剰酸素La系La_<1.8>Nd_<0.2>CuO_<4+δ>を作製し、この系で初めて1/8異常(p〜1/8において超伝導が抑制される現象)を発見した。さらに、Cuサイトを1%Znで置換すると、1/8異常は顕著になることが分かった。したがって、1/8異常はCuO_2面を有する高温超伝導体に共通の現象であると結論できた。
3.La系高温超伝導体La_<2-x>CuO_4のx=1/8付近(正確にはx=0.11)の大型単結晶について、低温でホール係数の符号が反転して負になることを実験的に明らかにした。この結果は、電荷とスピンの静的なストライプ秩序が形成された低温の状態をモデル化した理論計算の結果とも一致した。
4.La系高温超伝導体La_<2-x>Sr_xCu_<1-y>Zn_yO_4のx=0.115と0.13において、Zn量を細かく変化させた試料を作製し、μSR実験を行い、0.075%位の少量のZn置換によって静的な磁気秩序力溌達し、Zn量が10%になると磁気相関が壊れることが分かった。この結果から、少量のZnは電荷とスピンの動的なストライプ秩序をピン止めし、静的なストライプ秩序の形成に有効であるが、多量のZnはストライプ相関を破壊するものと理解できた。
5.2次元反強磁性系Cu_3B_2O_6、および、2次元スピンギャッブ系SrCu_2(BO_3)_2において、低温で熱伝導度が著しく増大することを発見した。いずれも磁場の印加で抑制されるが、スピンの秩序状態が熱伝導を著しく増大させていることが分かった。

Report

(2 results)
  • 2001 Annual Research Report
  • 2000 Annual Research Report
  • Research Products

    (23 results)

All Other

All Publications (23 results)

  • [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"Journal of the Physical Society of Japan. 70・2. 437-444 (2001)

    • Related Report
      2001 Annual Research Report
  • [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)

    • Related Report
      2001 Annual Research Report
  • [Publications] Y.Koike: "Impurity Effects on the Stripes in the La-214, Bi-2212 and Y-123 Phases"AIP Conference Proceedings. 554. 202-208 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Y.Koike: "Cu-site-substitution effects on the 1/8 anomaly in the higy-T_c cuprates and on the anomaly at x=0.21 in La_<2-x>Sr_xCuO_4"Physica C. 357-360. 82-88 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] H.Kimura: "Neutron-Scattering study of Incommensureta 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. 70-Suppl.A. 52-54 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] Y.Koike: "Possible stripe ordering at x=0.21 in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Physica C. 364-365. 562-566 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Kudo: "Antiferromagnetic ordering in the single-crystal Cu_3B_2O_6"Journal of the Physical Society of Japan. 70・4. 935-938 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Kudo: "Thermal conductivity of the two-dimensional spin-gap system SrCu_2(BO_3)_2 in magnetic fields"Journal of the Physical Society of Japan. 70・6. 1448-1451 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] T.Adachi: "Crystal growth. transport properties, and crystal structure of the single-crystal La_<2-x>Ba_xCuO_4(x=0.11)"Physical Review B. 64. 144524-1-144524-7 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] I.Watanabe: "MSR study on the Cu-spin dynamics in La_<2-x>Sr_xCu_<1-y>Zn_yO_4"Journal of Physics and Chemistry of Solids. (印刷中).

    • Related Report
      2001 Annual Research Report
  • [Publications] 阿子島めぐみ: "Bi系・Y系高速超伝導体における1/8異常とストライプ"固体物理. 37・3(印刷中). (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] I.Watanabe: "Muon-spin-relaxation study on the Cu-spin state of Bi_2Sr_2 Ca_<1-x>Y_x (Cu_<1-y>Zn_y)_2O_<8+8> around the hole concentration of 1/8 per Cu"Physical Review B. 62・21. 14524-14530 (2000)

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

    • Related Report
      2000 Annual Research Report
  • [Publications] T.Kawamata: "Giant suppression of superconductivity at X=0.21 in the Zn-substituted La_<2-x>Sr_xCu_<1-y>Zn_yO_4single crystals"Physical Review B. 62・18. R11981-R11984 (2000)

    • Related Report
      2000 Annual Research Report
  • [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 μSR"Physical Review B. 62・18. R11985-R11988 (2000)

    • Related Report
      2000 Annual Research Report
  • [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"Journal of the Physical Society of Japan. 70・2(印刷中). (2001)

    • Related Report
      2000 Annual Research Report
  • [Publications] K.Kudo: "Sping gap of Sn_<4-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)

    • Related Report
      2000 Annual Research Report
  • [Publications] Y.Koike: "Impurity Effects on the Stripes in the La-214, Bi-2212 and Y-123 Phases"AIP Conference Proceedings. (印刷中).

    • Related Report
      2000 Annual Research Report
  • [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).

    • Related Report
      2000 Annual Research Report
  • [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).

    • Related Report
      2000 Annual Research Report
  • [Publications] Y.Koike: "Cu-site-substitution effects on the 1/8 anomaly in the high-Tc cuprates and on the anomaly at x=0.21 in La_<2-x>Sr_xCuO_4"Physica C. (印刷中).

    • Related Report
      2000 Annual Research Report
  • [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).

    • Related Report
      2000 Annual Research Report
  • [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).

    • Related Report
      2000 Annual Research Report

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Published: 2000-04-01   Modified: 2018-03-28  

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