NUCLEAR-RELAXATION OF HYDROGEN-DOPED ANTIFERROMAGNETIC YBA2CU3O6+XHY

Cu(1) NQR, Cu(2) zero field NMR, and proton NMR have been measured in the antiferromagnetic (AF) phase of a powdered sample of hydrogen-dope d YBa2Cu3O6.1H0.14 from 4.2 to 300 K. The line width of H-1 NMR increa ses abruptly below 20 K. The enhancements of T-2(-1) and T-1(-1) of Cu -63(1) NQR occur around 20 and 40 K, respectively. The relaxation mech anism of T-1 of NQR changes at T-rm = 80 K and the time dependence of its nuclear magnetization recovery shows a nonexponential type for T < T-rm and an exponential one for T > T-rm. The predominant source for T-1 below T-rm is found to be the fluctuating magnetic fields due to t he staggered Cu2+ moments induced by the hole doping effect. Above T-r m, T-1(-1) of NQR increases gradually with temperature but it is almos t temperature independent above 150 K, what can not be explained by th e effect of the ordered AF Cu2+ moments in the Cu(2)O-2 plane and also by the Raman process of the lattice vibrations.