Nuclear Relaxation and Knight Shift Studies of Copper in YBa2Cu3O7-y
Nuclear Relaxation and Knight Shift Studies of Copper in YBa2Cu3O7-y
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YBa2Cu3O7-y 中铜的核弛豫和奈特位移研究
DOI：
10.1143/jpsj.57.30
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发表时间：
1988
影响因子：
1.7
通讯作者：
K. Asayama
中科院分区：
文献类型：
--
作者：
Y. Kitaoka;S. Hiramatsu;T. Kondo;K. Asayama
通过铜核四极杆 (NQR) 和磁共振 (NMR) 技术研究了 Cu-O 平面和链位点的核弛豫率 1/ T 1 和奈特位移。在 T c =92 K 以下，平面位点的 1/ T 1 显着降低，而 BCS 超导体的 T c 特性以下没有增强，并且奈特位移也显示出比 BCS 预测更快的降低，这提供了占主导地位的单线态配对的证据。相反，链位点的1/T 1 在低于T c 时表现出弱的温度依赖性。平面和链 Cu 位点 1/ T 1 行为的差异归因于弛豫过程的差异，即分别为磁弛豫过程和四极弛豫过程。从1/T的行为和面位点的奈特位移来看，库珀对可能是由强耦合形成的具有大能隙的d型。
The nuclear relaxation rate 1/ T 1 and the Knight shift have been studied for boththe Cu–O plane and chain sites by Cu nuclear quadrupole (NQR) and magnetic resonance (NMR) techniques. Below T c =92 K, 1/ T 1 for the plane site decreases markedly without the enhancement just below T c characteristic for the BCS superconductor, and the Knight shift also shows a more rapid reduction than the BCS prediction, giving evidence of a dominant singlet pairing. In contrast, 1/ T 1 for the chain site shows a weak temperature dependence below T c . This difference of the 1/ T 1 behavior for the plane and chain Cu sites is attributed to the difference of the relaxation processes, i.e., the magnetic and quadrupole relaxation processes, respectively. From both the behaviors of 1/ T and the Knight shift at the plane site, it is pointed out that the Cooper pair may be of a d-type formed by a strong coupling with a large energy gap.