Nuclear-quadrupole-resonance study of overdoped Y1-xCaxBa2Cu3O7 - art. no.104514

We have performed a Cu-63,Cu-65 nuclear-quadrupole-resonance study of overd oped Y1-xCaxBa2Cu3O7 and find that the temperature dependence of the Cu spi n-lattice and spin-spin relaxation rates are similar to that in lightly ove rdoped YBa2Cu3O7. We show that the data can be interpreted within the Milli s, Monien, and Pines model in terms of no significant decrease in the antif erromagnetic correlation length, at least for p<0.233. Furthermore, the iso topic ratios of the spin-lattice and spin-spin relaxation rates do not chan ge with increasing hole concentration, indicating that magnetic relaxation is still dominant in the overdoped region.