NUCLEAR-SPIN RELAXATION AT PLANAR COPPER AND OXYGEN SITES IN YBA2CU3O6.96

The temperature dependence of the spin lattice relaxation rates (T1(-1)) at the planar copper (Cu(2)) and oxygen (O(2, 3)) sites in High-T(c) superconductor; YBa2Cu3O6.96 has been re-examined using an oriented powder sample. We have confirmed the existence of a characteristic region around T(c) where the degrees of suppression of both T1(-1),s are equivalent. At the lower temperature, the decrease of the relaxation rate at the Cu(2) sites was more rapid than that of the O(2, 3) sites, and obeyed the power law against the decrease of the O(2, 3) relaxation rate. This is in contrast with a previous report.