SPIN DYNAMICS STUDIED BY Y-89 NMR IN HIGH-TC SUPERCONDUCTOR YBA2CU3O6+X

Y-89 NMR shifts in the high T(c) superconductor YBa2Cu3O6+x are compared with O-17 NMR new data published by Yoshinari et al. and the orbital shift 89K(orb) is estimated to be 155 ppm. The nuclear spin lattice relaxation rate 89(1/T1T) for Y-89 is found to be proportional to 17(1/T1T) for O-17 at 2, 3 plane sites, which supports the single spin fluid model. The relation T1TK(S) = const. is realized for Y-89 nuclei in the oxygen depleted compounds YBaCu3O6+x. It is found that the relation T1TK(S) = const. means that the energy width of dynamical spin susceptibility chi-"(q, omega) with the wave vector q approximately 0, h-GAMMA-0, is independent of temperature although the uniform susceptibility chi-0 strongly depends on temperature. It is also shown that the weight of the low q part of the spin excitation spectrum decreases with decreasing the hole concentration.