RELATION BETWEEN IRREVERSIBILITY LINE AND VORTEX-GLASS LINE IN EPITAXIAL YBa2Cu3O7-δ THIN FILMS

Abstract

We have measured in detail the resistive transition and the isothermal current-voltage curves in the case of applied magnetic field parallel and perpendicular to the surface of the film up to 10T for an epitaxial YBa2Cu3O7-δ thin film, respectively. The comparative study of the irreversibility line from the R-T curves with the vortex-glass line from the I-V curves was made. The results showed that the irreversibility line determined from the different reduced resistivity criterion and vortex-glass line follow the same power law, H∝(T(0)-T(H))n, and n=4/3 for the vortex-glass line, n=3/2 for the irreversibility line. The irreversibility line is dependent not only on the different reduced resistivity criterion but also on the measuring current density. The vortex-glass line lies below the irreversibility line. The possible origin of the difference between such two lines was discussed.