Modeling the Critical Current of Polycrystalline Superconducting Films in High Magnetic Fields [dataset]

We have performed simulations using time-dependent Ginzburg—Landau theory on a 2D polycrystalline system where grain boundaries are modelled as narrow regions with a locally reduced critical temperature (Tc). For the small system sizes investigated, we find that the critical current density (Jc) is not sensitive to changes in grain size until the grain size is sufficiently small that it limits the average superparticle density in the system through the proximity effect. Furthermore, once Tc in the boundary regions is sufficiently low relative to the surrounding superconductor that grain boundary regions act as preferred channels for flux flow, further reductions in the boundary Tc only weakly reduce Jc across the superconductor.