NMR study of high-Tc superconductors

✍ Scribed by K. Asayama; G.-Q. Zheng; Y. Kitaoka; K. Ishida; K. Fujiwara

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 399 KB
• Volume: 178
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)90075-a

✦ Synopsis

From systematic measurements of TI, Knight shift, NQR frequency of 63Cu and ~70 with high-pressure measurement in high-Tc materials, La2_;,SrxCuO4, YBa2Cu307 and T12Ba2CuO6+ e the following results have been obtained. The staggered susceptibility at the zone boundary, X(Q) which is a measure of the antiferromagnetic spin fluctuation decreases in order of the La, Y and T1 system. X(Q) is governed by the number of Cu d-holes, n (Cu) and O p-holes, n (O) in the CuO2 plane, x(Q) increases when n(Cu)/n(O) increases. Tc increases and then decreases with n(Cu)/n(O) having a maximum at an optimum value of n(Cu)/ n (O). Correlation between X(Q) and Tc has been discussed by assuming X(Q) to play an essential role for the occurrence of high-Tc superconductivity. The T-dependence of 1/Tt below Tc suggests strongly the d-wave pairing model.