SPIN FLUCTUATIONS PARAMETERS IN TL2BA2CACU2O8-DELTA AS SEEN BY CU-63 AND O-17 NMR

The Cu-63 and O-17 NMR shift, T-1 and T-2G values measured in oriented Tl2Ba2CaCu2O8-delta sample (Tc=112 K) are reported. From analysis of these data in a frame of MMP model[1] we estimated the characteristic energy of spin fluctuation Gamma(Q), and the magnetic correlation leng th xi. The latter was approximately the same as reported for YBa2Cu3O7 , but Gamma(Q) is markedly larger compared with YBa2Cu3O7 and its magn itude grows with lowering the temperature. Probably the high Tc values in this class of superconductors is related to large value of Gamma(Q ), which could be considered as a strong argument in favour of spin fl uctuation mediated superconductivity. A similar conclusion has been do ne earlier for Tl2Ba2Ca2Cu3O10-delta by Zheng et al. [2].