Vortex dynamics in twinned superconductors

We numerically solve the overdamped equation of vortex motion in a twin-boundary (TB) superconductor, in which the applied Lorentz force ${F}_{L},$ the pinning forces due to TB's and point defects, and the intervortex interacting force are taken into account. Our simulations show that TB's act as easy flow channels for the vortex motion parallel to the TB's and obstructive barriers for that normal to the TB's. Due to the barrier effect, the transverse velocity of vortices increases with ${F}_{L},$ but if ${F}_{L}$ is strong enough, the vortices can cross through the TB's so that the transverse velocity vs ${F}_{L}$ curve exhibits peak behavior.