Effect of carrier distribution on superconducting characteristics of the multilayered high-Tccuprate(Cu0.6C0.4)Ba2Ca3Cu4O12+y:63Cu−NMRstudy
Effect of carrier distribution on superconducting characteristics of the multilayered high-Tccuprate(Cu0.6C0.4)Ba2Ca3Cu4O12+y:63Cu−NMRstudy
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DOI：
10.1103/physrevb.61.9707
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发表时间：
2000-04
影响因子：
3.7
通讯作者：
Y. Tokunaga;K. Ishida;Y. Kitaoka;K. Asayama;K. Tokiwa;A. Iyo;H. Ihara
中科院分区：
文献类型：
--
作者：
Y. Tokunaga;K. Ishida;Y. Kitaoka;K. Asayama;K. Tokiwa;A. Iyo;H. Ihara
本文报道了多层高Tc铜酸盐（Cu0.6C0.4）Ba 2Ca 3Cu 4 O 12 + y（Cu 1234）的Cu-NMR研究，Tc = 117 K.在正常态下，63 Cu的Knight位移（K）和核自旋-晶格弛豫速率（1/T1）表明内层CuO 2面（IP）是欠掺杂的，而外层CuO 2面（OP）是重掺杂的.在超导状态下，IP中的K和1/T1在Tc = 117 K以下显著下降，而OP中的K和1/T1在Tc = 117 K以下适度下降，但在Tc 2= 60 K以下显著下降。OP中不寻常的NMR结果表明SC能隙在Tc 2= 60 K时没有完全发展。从比较与传统的d波模型，它示出的SC间隙在OP线性增加低于Tc，并遵循T的依赖性低于Tc 2的平均场类型。我们认为这些差异是由于IP和OP之间掺杂水平的差异造成的。在Tc = 117 K处的体SC跃迁被认为是由Cu 1234中的欠掺杂IP触发的。
We report Cu-NMR studies of the multilayered high-T c cuprate (Cu 0.6 C 0.4) Ba 2 Ca 3 Cu 4 O 1 2+ y (Cu1234) with T c= 117 K. In the normal state, the Knight shift (K) and the nuclear spin-lattice relaxation rate (1/T 1) of 63 Cu give evidence that the inner CuO 2 planes (IP) are underdoped, whereas the outer ones (OP) are heavily overdoped. In the superconducting (SC) state, both K and 1/T 1 decrease markedly below T c= 117 K in the IP, whereas in the OP they decrease moderately below T c= 117 K, but markedly below T c 2= 60 K. The unusual NMR results in the OP reveal that the SC gap does not fully develop down to T c 2= 60 K. From comparison with a conventional d-wave model, it is shown that the SC gap in the OP increases linearly below T c and follows the mean-field type of T dependence below T c 2. We propose that these dissimilarities are caused by the large difference of doping levels between the IP and the OP. The bulk SC transition at T c= 117 K is considered to be triggered by the underdoped IP in Cu1234.