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Research on Spinel Trpe Cu sulfide Superconductors

尖晶石Trpe硫化铜超导体的研究

基本信息

批准号：
06640481
负责人：
MIYATANI Kazuo
金额：
$ 1.34万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06640481/
关键词：
thiospinels copper sulfides CuCo_2S_4 CuV_2S_4 CuRh_2S_4 itinerant antiferromagnet superconductors electron correlation spinels cupper sulfides antiferro super conductors spin correlation Jahn-Teller SCR theory copper sulfide

项目摘要

Superconductivity of Cu oxide high temperaturu superconductors is based on the electronic state of Cu(3d^9)-O(3p^6).To extend the understanding about the origin of the superconductivity, it is quite interesting to find basic properties of Cu(3d^9)-S(3p^6) orbits of Cu sulfide superconductors with low anisotropy. We performed exploratory work about various spinel type Cu sulfide superconductors, and found that the Cu_<1+X>Co_<2-X>S_4(x=0-0.5) system with a low spin state of Co^<3+>(3d^6) shows antiferromagnetic behavior at 20K and superconductor transition at 5K.Research activity was focused on this system and related Cu salfide materials of (Cu, M)Co_2S_4(M=Ni and Co), Cu[Cu_XRh_<2-X>]S_4 and CuV_2S_4. Hard work was needed to develop reproducible process of sample synthesis, and was a measure reason for the research schedule postponed a year. In fact, even today, the sample is produced in our laboratory only in the world in spite the unique material was found 5 years ago. The high quality sample are now available, and the magnetism and superconductivity data are being renewed well.Inthis program, material synthesis, crystallographic data, electronic conductivity, superconductivity and microscopic NMR data were studied with the collaborate teams and obtained very effective yields. Material synthesis and the basic properties were done in Ehime University, some low temperture measurements in Solid State Technical Institute for Tokyo University, standard NMR study in Tokushima University and advanced NMR study in Kobe University. As the result, various unique phenomena and physics were obtained to explain the superconductivity, spin correlation, and electron correlation in the Cu(3d)-S(3p) system, and we have published 12 major technical papers.Low temperature specific heat, neutron diffraction, Seebeck effect and higt-pressure effect are also being studied and stimulating results are being given. These are targeted to explore in near future.

Cu氧化物高温超导体的超导性是基于Cu(3d^9)-O（3p^6）的电子态。为了扩展对超导性起源的理解，发现具有低各向异性的硫化铜超导体的Cu(3d^9)-S（3p^6）轨道的基本性质是非常有趣的。我们对各种尖晶石型硫化铜超导体进行了探索性研究，发现具有低自旋态Co^<3+>(3d^6)的Cu_<1+X>Co_<2-X>S_4（X =0-0.5）体系在20K表现出反铁磁行为，在5K表现出超导体跃迁。主要研究了该体系及其相关的Cu硫化材料（Cu， M）Co_2S_4（M=Ni和Co）、Cu[Cu_XRh_<2-X>]S_4和CuV_2S_4。开发可重复的样品合成工艺需要艰苦的工作，这是研究计划推迟一年的一个重要原因。事实上，即使在今天，我们的实验室也只在世界上生产样品，尽管这种独特的材料是在5年前发现的。目前已经获得了高质量的样品，磁性和超导性数据也得到了很好的更新。在这个项目中，与合作团队一起研究了材料合成、晶体学数据、电子导电性、超导性和微观核磁共振数据，并获得了非常有效的产量。材料的合成和基本性质在爱媛大学进行，低温测试在东京大学固体技术研究所进行，标准核磁共振研究在德岛大学进行，高级核磁共振研究在神户大学进行。获得了Cu(3d)-S（3p）体系中超导性、自旋相关、电子相关等多种独特现象和物理现象，并发表了12篇主要技术论文。对低温比热、中子衍射、塞贝克效应和高压效应也进行了研究，并给出了令人鼓舞的结果。这些都是在不久的将来要探索的目标。