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.

我们对高温铜酸盐及相关铜酸盐中的电荷和/或自旋序进行了研究，以获得高温超导机理的一些信息，得到的结果如下： 1． 1/8异常，即部分Zn掺杂的Bi-2212铜酸盐以及在空穴浓度p=1/8/Cu时对超导性的异常抑制La-214铜酸盐。我们还从μ子自旋弛豫测量中发现，在p=1/8时，Zn掺杂的Bi-2212和Y-123铜酸盐的自旋相关性增强。得出结论，1/8异常是高T_c铜酸盐所共有的。2．我们发现了超导性的异常抑制和自旋相关性的增强。 La_<2-x>Sr_xCu_<1-y>Zn_yO_4中x=0.21 通过对x=0.21、y=0.01的单晶的中子散射实验，我们在(π,π)附近观察到了不相称的磁峰。与 p=1/8 时观察到的结果类似，因此，自旋和空穴的动态条带顺序很可能被固定。 Zn，在x=0.21和p=1/8.3处导致静态条带序和超导性抑制。从以上结果可以得出结论，自旋和空穴的条带相关性存在于大范围的空穴中。浓度，并且它们可能在高温超导的出现中发挥重要作用。 4．我们研究了自旋梯铜酸盐。 Sr_<14>Cu_<24>O_<41>从传输测量中得出结论，空穴在低温下配对而不是形成电荷密度波我们还发现该系统中由于自旋而产生的热导率异常大。 。

项目成果

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）。 ）

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）

I.Watanabe: "Anomalous slowing down of Cu-spin fluctuations observed by muon spin relaxation to the Zn-substituted Bi_2Sr_2Ca_<1-x>Y_x (Cu_<1-y>Zn_y)_2 o_<8+S> system around-the hole concentration of 1/8 perCn"Physical Review B. 60・14. R9955-R9958 (1999)

I.Watanabe：“通过对 Zn 取代的 Bi_2Sr_2Ca_<1-x>Y_x (Cu_<1-y>Zn_y)_2 o_<8+S> 系统的 μ 子自旋弛豫观察到 Cu 自旋波动的异常减慢。 1/8 perCn“物理评论B.60・14浓度的孔。R9955-R9958（1999）

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）。

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)。