Influence of random point defects introduced by proton irradiation on the flux creep rates and magnetic field dependence of the critical current density Jc of co-evaporated GdBa2Cu3O7−δ coated conductors

Abstract

We report the influence of random point defects introduced by 3 MeV proton irradiation (doses of 0.5 × 1016, 1 × 1016, 2 × 1016 and 6 × 1016 cm−2) on the vortex dynamics of co-evaporated 1.3 μm thick, GdBa2Cu3O7−δ coated conductors. Our results indicate that the inclusion of additional random point defects reduces the low field and enhances the in-field critical current densities Jc. The main in-field Jc enhancement takes place below 40 K, which is in agreement with the expectations for pinning by random point defects. In addition, our data show a slight though clear increase in flux creep rates as a function of irradiation fluence. Maley analysis indicates that this increment can be associated with a reduction in the exponent μ characterizing the glassy behavior.