Nernst Effect And Superconducting Fluctuations In Zn-Doped Yba2cu3o7-Delta

We report the measurements of in-plane resistivity, Hall effect, and Nernst effect in Zn-doped YBa2Cu3O7-delta epitaxial thin films grown by pulsed laser deposition technique. The pseudogap temperature T-*, determined from the temperature dependence of resistivity, does not change significantly with Zn doping. Meanwhile the onset temperature (T-nu) of anomalous Nernst signal above T-c0, which is interpreted as evidence for vortex-like excitations, decreases sharply as the superconducting transition temperature T-c0 does. A significant decrease in the maximum of vortex Nernst signal in mixed state is also observed, which is consistent with the scenario that Zn impurities cause a decrease in the superfluid density and therefore suppress the superconductivity. The phase diagram of T-*, T-nu, and T-c0 versus Zn content is presented and discussed.