Study of long-range order of charges and/or spins in low-dimensional cuprates

低维铜氧化物中电荷和/或自旋的长程有序研究

• 批准号: 10440098
• 负责人: KOIKE Yoji
• 金额: $ 8.13万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10440098/
• 关键词: high-T_c superconductivity; 1; 8 anomaly; stripe; muon-spin-realxation; neutron scattering; transport properties; spin ladder; Sr_<14>Cu_<24>O_<41>; 単結晶育成; ホール効果; MSR; 非線形伝導

We have studied charge and/or spin order in the high-T_c cuprates and related cuprates, in order to obtain some informations on the mechanism of high-T_c superconductivity. The results obtained are as follows.1. We have discovered the so-called 1/8 anomaly, namely, the anomalous suppression of superconductivity at the hole concentration p=1/8 per Cu in the partially Zn-doped Bi-2212 cuprates as well as in the La-214 cuprates. We have also found from the muon-spin-relaxation measurements that the spin correlation is enhanced at low temperatures at p=1/8 in the Zn-doped Bi-2212 and Y-123 cuprates. Accordingly, it is concluded that the 1/8 anomaly is common to the high-T_c cuprates.2. We have discovered anomalous suppression of superconductivity and enhancement of the spin correlation at x=0.21 in La_<2-x>Sr_xCu_<1-y>Zn_yO_4. From the neutron scattering experiment of the single crystal with x=0.21 and y=0.01, we have observed incommensurate magnetic peaks around (π, π), which is similar to those observed at p=1/8. Accordingly, it is very likely that the dynamical stripe order of spins and holes is pinned by Zn, leading to the static stripe order and the suppression of superconductivity at x=0.21 as well as at p=1/8.3. From the above results, it is concluded that the stripe correlations of spins and holes exist in a wide range of hole concentration and that there is a possibility that they play an important role in the appearance of high-T_c superconductivity.4. We have studied the spin ladder cuprate Sr_<14>Cu_<24>O_<41> from the transport measurements, and concluded that holes are paired at low temperatures rather than form charge density wave. We have also found that the thermal conductivity due to spins is anomalously large in this system.

我们研究了高T_c铜酸盐及相关铜酸盐中的电荷和/或自旋有序，以获得关于高T_c超导电性机制的一些信息。取得的结果如下：1.研究结果。我们发现了所谓的1/8反常，即在部分掺锌的Bi2212铜酸盐和La-214铜酸盐中，当空穴浓度p=1/8per Cu时，超导电性的反常抑制。我们还从介子自旋弛豫测量中发现，在p=1/8的低温下，掺锌的Bi-2212和Y-123铜酸盐的自旋关联增强。由此得出结论：1/8异常是高T_c铜的共性。我们发现在x=0.21时，La_xCu_t；2-x&gt；Sr_xCu_&lt；1-y&gt；在x=0.21和y=0.01时的单晶的中子散射实验中，我们在(π，π)附近观察到了与p=1/8时相似的无公度磁峰。因此，很可能是动态的自旋和空穴的条带有序被锌钉扎，导致在x=0.21时和在p=1/8.3时的静态条带有序和超导电性的抑制。从以上结果可以得出结论，自旋和空穴的条纹关联存在于很大的空穴浓度范围内，并且它们可能在高T_c超导的出现中起着重要的作用。我们从输运测量出发，研究了自旋梯形铜酸盐Sr_&lt；14&gt；Cu_&lt；24&gt；O_&lt；41&gt；，得出了低温下空穴成对而不是形成电荷密度波的结论。我们还发现，在这个系统中，由于自旋引起的导热系数反常地大。

项目成果

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

K.Kubo：“通过电阻率和热导率研究Sr_<14-x>A_xCu_<24>O_<41>（A=Ca和La）单晶的自旋间隙和空穴配对”《低温物理学杂志》117。・5/6。1689-1693（1999）

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

M.Akoshima：“关于Y_<1-x>Ca_xBa_2Cu_3O_<7-δ>中的60K高原与1/8问题的关系”日本物理学会杂志67・10 3653-3654（1998年）。 ）

I.Watanabe, M.Aoyama, M.akoshima, K.Nishimaki, T.Kawamata, T.Adachi, Y.Koike, S.Ohira, W.Higemoto and K.Nagamine: "μSR study on the Cu-spin state in La_<2-x>Sr_xCu_<1-y>Zn_yO_4."International Journal of Modern Physics B. (in press).

I.Watanabe、M.Aoyama、M.akoshima、K.Nishimaki、T.Kawamata、T.Adachi、Y.Koike、S.Ohira、W.Higemoto 和 K.Nagamine：“Cu 自旋态的 μSR 研究La_<2-x>Sr_xCu_<1-y>Zn_yO_4。“国际现代物理学杂志 B.（出版中）。

H.Kimura, K.Hirota, M.Aoyama, T.Adachi, T.Kawamata, Y.Koike, K.Yamada and Y.Endoh.: "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 Jap. (in press).

H.Kimura、K.Hirota、M.Aoyama、T.Adachi、T.Kawamata、Y.Koike、K.Yamada 和 Y.Endoh.：“La_<2-x> 中不相称弹性磁峰的中子散射研究

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

I. Watanabe：“Zn 取代的 Bi-2212 系统磁态的 μSR 研究”Physica B. 259-261 (1999)。