Relaxation mechanisms for Cu-63,Cu-65 nuclear quadrupole resonance in Zn-doped YBa2Cu3O7

Abstract

We have prepared Zn-doped YBa2Cu3-xZnxO7, x=0 similar to 0.09 and performed Cu-63,Cu-65 nuclear quadrupole resonance measurements for the plane sites at 300 and 100 K as a function of Zn concentration. Both spin lattice and spin-spin relaxation rates are reduced for high Zn concentration. The reduction of spin-lattice relaxation rate due to Zn doping is more significant at the lower temperature. The ratio of Cu-63,Cu-65 spin-lattice relaxation rates indicates that the magnetic contribution to the spin-lattice relaxation rate for the plane copper is reduced whereas the quadrupolar contribution is increased at the lower temperature. This confirms clearly that the antiferromagnetic spin fluctuation of the plane copper moments is suppressed significantly by Zn substitution, [S0163-1829(99)00717-1].