NMR in high-Tc oxide superconductors

✍ Scribed by Yoshio Kitaoka; Kenji Ishida; Shigeki Ohsugi; Kenji Fujiwara; Kunisuke Asayama

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 405 KB
• Volume: 185-189
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)91957-6

✦ Synopsis

63Cu NQR and NMR studies are extensively reported in La2_xSrxCuO4(LSCO), heavilydoped TI2Ba2CuO6+y(TBCO)

and Zn-doped YBa2Cu307(YBCOy). The nuclear spin-lattice relaxation (T 1) study extracts that the antiferromaEnetic (AF) spin correlation becomes less distinct with decreasing T c in heavily-doped TBCO over an optimum hole content. In non-superconducting TBCO, the AF spin correlation disappears, sugEesting an intimate interrelation between the occurrence of the superconductivity and the presence of the AF spin correlation. In superconducting state, both the T 1 and Knight shift results in undoped-and Zn-doped YBCO7 are consistently understood within a simple model combining both effects of the gap zeros of lines at the Fermi surface arising from d-wave pairing and of the small but finite residual density of states at the Fermi level induced by some impurity and some imperfection.