Magnetoresistance probe of spatial current variations in high-T c YBa2Cu3O7–SrRuO3–YBa2Cu3O7 Josephson junctions

Abstract

The low frequency current–voltage characteristics of YBa₂Cu₃O₇–SrRuO₃–YBa₂Cu₃O₇ Josephson junctions show an increasing resistance and phase shift in fields of 0 to 8 T. A critical current is also evident up to 8 T. Data are analyzed in terms of field‐induced perturbations of the current paths through the junction. Results indicate a highly inhomogeneous interface where the mean width of spatial variations in both normal and supercurrent is of order 50 to 100 Å.