The Cu-63 and O-17 NMR studies of spin susceptibility in differently dopedTl2Ba2CaCu2O8-delta compounds

The NMR line shifts, spin-lattice relaxation rate T-1(-1) of Cu-63 and O-17 and Cu-63 spin-spin relaxation rate T-63(2)-1 were measured in normal and superconducting states of the magnetically oriented ceramics of Tl2Ba2CaCu2 O8-delta with different hole concentrations (T-c = 102 K, T-c = 112 K, T-c = 104 K) involving the optimally doped composition (T-c = 112 K). The magne tic hyperfine fields on the Cu and O atoms in the CuO2 layer were estimated using the temperature dependences of the Knight shift. The temperature dep endences of magnetic correlation length xi and characteristic energy Gamma( Q) of antiferromagnetic (AF) spin fluctuations were analyzed using the T-63 ,17(1)-1 and T-63(2)-1 data obtained. In going to overdoped state of cuprat e the crossover in temperature between different regimes of spin fluctuatio ns is discussed taking into account the magnetic phase diagram proposed for superconducting cuprates by Barzykin and Pines [V. Barzykin, D. Pines, Phy s. Rev. B 52 (1995) 13585]. (C) 1999 Published by Elsevier Science B.V. All rights reserved.