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

非常规超导性经常出现在与强电子-电子相关性相关的磁有序附近，众所周知，正常状态的特征是强各向异性和强电子-电子相关性，这在高T2C ED2铜酸盐中是典型的。为了了解正常状态下这些特性对超导性的影响，我们在氧化物超导体中进行了压力实验。（1）压力诱导的可能性SrD22D2RuOD24As 中的铁磁性是已知的压力，它可以控制电子-电子相关性，是发现 SrD22D2RuOD24D2 系统中磁巨态的合适技术，我们测量了 SrD22D2RuOD24D2 中电阻率的温度和压力依赖性。 40K 在 1.5-5GPa 下发现面内电阻率的温度依赖性。此外，在 5GPa 以上抑制驼峰后，电阻率显示出 T14/3D1 依赖性。这些行为表明存在压力诱导的铁磁性。（ 2）二维电子态在超导中的作用LaD22-xD2SrD2xD2CuOD24强二维性（以c轴电阻率的奇异行为表示）是氧化物超导体的关键特征，尽管低维性通常被认为是传统超导性的破坏因素。在电子态反映在T2D2中，我们测量了LaD22-xD2SrD2xD2CuOD24D2 在各向异性压力下的 c 轴电阻率 c 轴压缩降低了 c 轴电阻率，从而降低了 TyD2c D2 锐角，而 c 轴延伸则增加了 c 轴电阻率，从而提高了 38K 的 D2。环境压力至 51 .6K我们发现 T2D2 的变化是 c 轴电阻率的函数，并且 c 轴压力系数比 ab 轴压力系数强得多，这意味着 T D2cIeD2 主要取决于夹层，而不是面内晶格参数。