超伝導CuCoS系化合物における核スピン格子緩和時間と反強磁性スピン相関

超导 CuCoS 基化合物中的核自旋-晶格弛豫时间和反铁磁自旋相关性

• 批准号: 07640478
• 负责人: 和田 信二
• 金额: $ 1.34万
• 依托单位: Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-07640478/
• 关键词: 反強磁性スピン相関; 超伝導; 核スピン格子緩和時間; 銅スピネル硫化物

今までのNMR研究により、スピネル型結晶構造を持つ銅硫化物Cu_<1.5>Co_<1.5>S_4における超伝導の発現は,4面体サイトの銅イオンの反強磁性スピンの揺らぎの増大と強い相関を明らかにしてきた.本研究では銅置換量を系統的に変化させたCu_<1+x>Co_<2-x>S_4(x=1〜0.5)の領域に研究を広げてその本質をしらべた.その結果1.NMRスペクトルの解析から,x>0のCu-rich領域では,八面体BサイトにCuを置換することができず,x=0.5の仕込組成で作成した試料はCuCo_2S_4であることが判明した.従って(Cu_<1-x>Co_x)Co_2S_4(x=0〜1)が研究対象となった.2.核スピン格子緩和時間およびナイトシフトの温度依存性の測定により,x→1 (CuCo_2S_4)に漸近するに伴って,局在性のやや強いCuスピンの反強磁性スピンの揺らぎが増大するとともに超伝導転移温度が上昇する.3.CuCo_2S_4-CoCo_2S_4の昼間領域ではパウリ常磁性を示すがx→0(CuCo_2S_4)に漸近するに伴って,こんどはCoイオンのスピンによる遍歴電子型の弱磁性が出現する.などを明らかにした.今後も引き続き,CuCo_2S_4-CoCo_2S_4の全領域にわたってd電子の強い相関が引き起こす多様な物性の発現機構を明らかにしていくとともに,CuCo_2S_4の核スピン格子緩和時間の超伝導領域での温度依存性をHe3の低温領域まで測定し,この系における超伝導波動関数の対称性を調べていく.

In recent years, NMR research results show that the superconductor of sulphide Cu_<1.5>Co_<1.5>S_4 is sensitive to the tetrahedron, and the magnetic properties of the tetrahedron are very strong. The purpose of this study is to improve the performance of the measurement system. Cu & lt;1+x>Co_<2-x>S_4 (x = 1: 0. 5) is used in the field of research in this field. According to the results of the 1.NMR experiment, the data analysis shows that the Cu-rich domain is zero, the octahedron B is located, the octahedron is Cu, and the composition of the octahedron is 0.5. The composition of the octahedron is used to determine the accuracy of the CuCo_2S_4 system. The study of "Cu_<1-x>Co_x" (Cu_<1-x>Co_x) Co_2S_4 (xylene 0.1) is similar to that of others. 2. The temperature dependence of temperature dependence is measured by nuclear checklist and time monitoring. X-ray 1 (CuCo_2S_4) is used to determine the temperature dependence. The local Cu system is sensitive to the strong magnetic field. The temperature of the overload temperature is higher than that of the normal magnetic field. The 3.CuCo_2S_4-CoCo_2S_4 field temperature measurement shows that the Co temperature is very close to the temperature, and the electronic weak magnetic field is found all over the world. I don't know what's going on. In the future, CuCo_2S_4-CoCo_2S_4 has introduced a wide range of physical property management systems, such as He3 temperature dependence, temperature dependence and temperature dependence. It is known that the number of ultra-high-speed guided waves is symmetrical.

项目成果

Y. Furukawa: "NMR Study of the Magnetism and Superconductivity in Cu_<1+x>Co_<2-x>S_4" Advance in Superconductivity VII. 1. 155-158 (1994)

Y. Furukawa：“Cu_<1x>Co_<2-x>S_4 中磁性和超导性的核磁共振研究”超导进展 VII。

Y. Furukawa: "Nuclear spin-lattice relaxation and antiferromagnetic spin correlations in superconducting thiospinel Cu_<1.5>Co_<1.5>S_4" Physical Review B (condensed Matter). 51. 6159-6162 (1995)

Y. Furukawa：“超导硫尖晶石 Cu_<1.5>Co_<1.5>S_4 中的核自旋晶格弛豫和反铁磁自旋相关性”物理评论 B（凝聚态）。