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

The in-plane resistance of two single crystals of YBa{sub 2}(Cu{sub 1{minus}0.01{ital x}}Zn{sub 0.01{ital x}}){sub 3}O{sub 7{minus}{delta}}, {ital x}=1 and 3.5, was measured in magnetic fields up to 12 T parallel to the {ital c} axis at temperatures {epsilon}=ln({ital T}/{ital T}{sub {ital c}}) up to about 1/3. The coherence lengths and the phase-breaking scattering time {tau}{sub {phi}} were determined. {xi}{sub {ital ab}} and {xi}{sub {ital c}} were both found to decrease with Zn doping, with a slow increase of the anisotropy ratio {xi}{sub {ital ab}}/{xi}{sub {ital c}}. The phase-breaking scattering rate 1/{tau}{sub {phi}} increases strongly with increasing Zn concentration, indicating that Zn causes pair breaking in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}.