Vortex plastic flow, local flux density, magnetization hysteresis loops, and critical current, deep in the Bose-glass and Mott-insulator regimes

Abstract

We present simulations of flux-gradient-driven superconducting vortices interacting with strong columnar pinning defects as an external field $H(t)$ is quasistatically swept from zero through a matching field ${B}_{\ensuremath{\varphi}}$. We analyze several measurable quantities, including the local flux density $B(x, y, H(t))$, magnetization $M(H(t))$, critical current ${J}_{c}(B(t))$, and the individual vortex flow paths. We find a significant change in the behavior of these quantities as the local flux density crosses ${B}_{\ensuremath{\varphi}}$, and quantify it for many microscopic pinning parameters. Further, we find that for a given pin density ${J}_{c}(B)$ can be enhanced by maximizing the distance between the pins for $B<{B}_{\ensuremath{\varphi}}$.