Ru NQR Probe of Superconducting Property in Impurity-Doped CeRu 2
Ru NQR Probe of Superconducting Property in Impurity-Doped CeRu 2
复制标题
掺杂CeRu 2 超导Ru NQR探针
DOI：
10.1143/jpsj.67.2101
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发表时间：
1998
影响因子：
1.7
通讯作者：
K. Asayama
中科院分区：
文献类型：
--
作者：
H. Mukuda;K. Ishida;Y. Kitaoka;K. Asayama
通过在零磁场下采用 NQR 技术系统测量纯 CeRu 2 和杂质取代的 CeRu 2 上 101 Ru 的核自旋晶格弛豫率 1/ T 1 ，研究了 CeRu 2 的超导特性。 CeRu 2 的 (1/ T 1 ) 显示出略低于 T c 的宽相干平台，随后呈指数下降，远低于 T c 。相比之下，在杂质取代的 CeRu 2 的 T c 下方发现了 (1/ T 1 ) 的明显相干峰，尽管 Ce 和 Ru 位点的 La 和 Al 取代分别使 T c 略有增加和减少。人们认为杂质散射使能隙的各向异性平均化，这与安德森的脏超导体理论非常一致。正常状态下的 101 (1/ T 1 T ) 与费米能级态密度 N 2 ( E F ) 的平方成正比，发现随着 Al 含量的增加而减小。通过用非磁性 Al 杂质替代 Ru 位置来抑制 T c...
Superconducting characteristics of CeRu 2 have been investigated by systematic measurements of the nuclear-spin lattice relaxation rate, 1/ T 1 of 101 Ru on pure and impurity-substituted CeRu 2 , employing an NQR technique in zero magnetic field. (1/ T 1 ) for CeRu 2 shows a broad coherence plateau just below T c followed by an exponential decrease well below T c . By contrast, a distinct coherence peak of (1/ T 1 ) has been found just below T c for the impurity-substituted CeRu 2 , even though La- and Al-substitutions for the Ce and Ru sites make T c slightly increase and decrease, respectively. It is considered that the impurity scattering averages out the anisotropy of the energy gap, in good agreement with the theory of dirty superconductors by Anderson. 101 (1/ T 1 T ) in the normal state, which is in proportion to the square of the density of states at the Fermi level, N 2 ( E F ), is found to decrease with the Al content. The suppression in T c by substituting nonmagnetic Al impurity for the Ru sit...