INCREASED PHASE-BREAKING SCATTERING RATE IN ZN-DOPED YBA2CU3O7-DELTA

The in-plane resistance of two single crystals of YBa2(Cu1-0.01xZn0.01 x)(3)O-7-delta, x=1 and 3.5, was measured in magnetic fields up to 12 T parallel to the c axis at temperatures epsilon=ln(T/T-c) up to about 1/3. The coherence lengths and the phase-breaking scattering time tau (phi) were determined. xi(ab) and xi(c) were both found to decrease wi th Zn doping, with a slow increase of the anisotropy ratio xi(ab)/xi(c ). The phase-breaking scattering rate 1/tau(phi) increases strongly wi th increasing Zn concentration, indicating that Zn causes pair breakin g in YBa2Cu3O7-delta.