Pressure effect on the 2D-electronic state and the superconductivity in oxide superconductors

压力对氧化物超导体中二维电子态和超导性的影响

基本信息

批准号：
10640349
负责人：
NAKAMURA Fumihiko
金额：
$ 1.86万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Unconventional superconductivity is frequently found at adjacencies of the magnetic ordering related to strong electron-electron correlation. It is known that the normal state is characterized by strong anisotropy and strong electron-electron correlation, as is representatively seen in high-TィイD2cィエD2 cuprates. To understand the effect of these characters in normal state on the superconductivity, we perform pressure experiments in oxide superconductors.(1) Possibility of pressure induced ferromagnetism in SrィイD22ィエD2RuOィイD24ィエD2As is known pressure, which can control the electron-electron correlation is suitable technique to discover the magnetic grand state in SrィイD22ィエD2RuOィイD24ィエD2 system. We measure temperature and pressure dependence of resistivity in SrィイD22ィエD2RuOィイD24ィエD2. A pressure induce hump at around 40K is found in the temperature dependence of in-plane resistivity under 1.5-5GPa. Moreover, the resistivity shows TィイD14/3ィエD1 -dependence after suppressing the hump under pr … More essure over than 5GPa. These behaviors strongly indicate a pressure-induced ferromagnetism.(2) Role of two-dimensional electronic state in superconductivity in LaィイD22-xィエD2SrィイD2xィエD2CuOィイD24ィエD2Strong two-dimensionality, which is after expressed in exotic behavior of the c-axis resistivity, is a key character of oxide superconductors, though low dimensionality is generally known as a destructive factor for conventional superconductivity. To explore how the two-dimensionality in the electronic state is reflected in TィイD2cィエD2, we have measured the c-axis resistivity for LaィイD22-xィエD2SrィイD2xィエD2CuOィイD24ィエD2 under anisotropic pressure. The c-axis compression, which decreases the c-axis resistivity, reduces TィイD2cィエD2 drastically, whereas c-axis extension, which increases the c-axis resistivity, enhances TィイD2cィエD2 from 38K at ambient pressure to 51 .6K at 8GPa. We find that the variation of TィイD2cィエD2 scales as a function of the c-axis resistivity, and that the c-axis pressure coefficient is much stronger than the ab-axis one, These imply that TィイD2cィエD2 depends primarily on the interlayer, rather than the in-plane, lattice parameter. Less

在与强电子电子相关相关的磁顺序的邻接处经常发现非常规的超导性。众所周知，正常状态的特征是强烈的各向异性和较强的电子电子相关性，正如在高三键D2CIE D2蛋白酶中所代表的那样。 To understand the effect of these characters in normal state on the superconductivity, we perform pressure experiments in oxide superconductors.(1) Possibility of pressure induced ferromagnetism in Sri D22RuOi D24D2As is known pressure, which can control the electron-electron correlation is suitable technique to discover the magnetic grand state in Sri D22RuOi D24D2 system.我们测量SRI D22RUOI D24D2中电阻的温度和压力依赖性。在1.5-5GPA以下的平面内耐药温度依赖性中，发现驼峰在40k左右。此外，耐药物显示了TYI D14/3E D1在抑制PR下的驼峰之后的依赖性……比5GPA高。 These behaviors strongly indicate a pressure-induced ferromagnetism.(2) Role of two-dimensional electronic state in superconductivity in Lai D22-xE D2Sri D2xE D2CuOi D24E D2Strong two-dimensionality, which is after expressed in exotic behavior of the c-axis resistant, is A key character of oxide superconductors, though low dimension is generally known as a传统超导性的破坏性因素。为了探索如何在TYI D2CIE D2中反映电子状态中的二维性，我们已经在各向异性压力下测量了LAI D22-X D2X D2X D2CUOI D24I D2的LAI D22-X D2SRI D2X D2C d2cUOI D23的C轴抗性。 C轴压缩降低了C轴抗性，可大大降低D2CIéD2，而C轴扩展会增加C轴电阻，从而使T2CIUL D2从38K从环境压力下的38K提高到8GPA时的51 .6K。我们发现T2CIéD2尺度的变化是C轴电阻的函数，并且C轴压力系数远比AB轴强得多，这些都意味着T2CIUR D2主要取决于中间层，而不是平面内晶格参数。较少的