Vortex Plastic Flow, $B(x,y,H(t)),M(H(t)),J_c(B(t))$, 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 quasi-statically swept from zero through a matching field $B_{\varphi }$. 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 $B_{\varphi }$, 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 $B<B_{\varphi }$.

4 pages, 4 PostScript Figures