Effect of carrier distribution on superconducting characteristics of the multilayered high-Tc cuprate (Cu0.6C0.4)Ba2Ca3Cu4O12+y: 63Cu−NMR study

作     者：Y. Tokunaga K. Ishida Y. Kitaoka K. Asayama K. Tokiwa A. Iyo H. Ihara 

作者机构：Core Research for Evolutional Science and Technology (CREST) of the Japan Science and Technology Corporation (JST) Kawaguchi Saitama 332-0012 Japan 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2000年第61卷第14期

页      面：9707-9707页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：We report Cu-NMR studies of the multilayered high-Tc cuprate (Cu0.6C0.4)Ba2Ca3Cu4O12+y (Cu1234) with Tc=117 K. In the normal state, the Knight shift (K) and the nuclear spin-lattice relaxation rate (1/T1) of 63Cu give evidence that the inner CuO2 planes (IP) are underdoped, whereas the outer ones (OP) are heavily overdoped. In the superconducting (SC) state, both K and 1/T1 decrease markedly below Tc=117 K in the IP, whereas in the OP they decrease moderately below Tc=117 K, but markedly below Tc2=60 K. The unusual NMR results in the OP reveal that the SC gap does not fully develop down to Tc2=60 K. From comparison with a conventional d-wave model, it is shown that the SC gap in the OP increases linearly below Tc and follows the mean-field type of T dependence below Tc2. 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 Tc=117 K is considered to be triggered by the underdoped IP in Cu1234.