Cu NMR and NQR Studies of High-Tc Superconductor La2-xSrxCuO4.
Cu NMR and NQR Studies of High-Tc Superconductor La2-xSrxCuO4.
复制标题
高温超导体 La2-xSrxCuO4 的 Cu NMR 和 NQR 研究。
DOI：
10.1143/jpsj.63.700
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发表时间：
1994
影响因子：
1.7
通讯作者：
K. Asayama
中科院分区：
文献类型：
--
作者：
S. Ohsugi;Y. Kitaoka;K. Ishida;G. Zheng;K. Asayama
对x =0.075 ~ 0.24的超导材料la2 - x Sr x cuo4进行了广泛的Cu NMR和NQR研究。原子核自旋-晶格弛豫速率（1/ t1）的快速下降和自旋Knight位移在温度以下，微观上证实了在0.10≤x≤0.24时，温度低于38 K的超导相的存在。当x =0.10时，样品的一小部分在低T处出现磁异常，例如：与T无关的t1和谱宽，与x =0.125的la2 - x Ba x cuo4的磁序有一定关系。对于x >0.15, t1 =const。在温度远低于温度的情况下，残余自旋Knight位移的存在表明，在费米能级上，由于不同结构（即四方和正交）的混合，超导性是一种具有有限态密度的无间隙型。
Results of extensive Cu NMR and NQR studies in the superconducting La 2- x Sr x CuO 4 with x =0.075∼0.24 have been presented. The rapid decrease of the nuclear spin-lattice relaxation rate, 1/ T 1 , and the spin Knight shift below T c confirm microscopically the existence of the superconducting phase with lower T c than 38 K for 0.10 ≤ x ≤0.24. For x =0.10, magnetic anomalies emerge at low- T in some small parts of the sample, e.g . T -independent T 1 and broadening of spectrum, having some relevance to the magnetic order in La 2- x Ba x CuO 4 with x =0.125. For x >0.15, the T 1 T =const. behavior and the existence of the residual spin Knight shift far below T c have revealed that the superconductivity is of a gapless type with a finite density of states at the Fermi level caused by the mixture of different structures, i.e. tetragonal and orthorhombic.