Vortex transport in a channel with periodic constrictions

By numerically solving the time-dependent Ginzburg-Landau equations in a type-II superconductor, characterized by a critical temperature T_c1, and the coherence length ξ₁, with a channel formed by overlapping rhombuses (diamond-like channel) made of another type-II superconductor, characterized, in general, by different T_c2 and ξ₂, we investigate the dynamics of driven vortex matter for varying parameters of the channel: the width of the neck connecting the diamond cells, the cell geometry, and the ratio between the coherence lengths in the bank and the channel. We analyzed samples with periodic boundary conditions (which we call ‘infinite’ samples) and finite-size samples (with boundaries for vortex entry/exit), and we found that by tuning the channel parameters, one can manipulate the vortex dynamics, e.g., change the transition from flux-pinned to flux-flow regime and tune the slope of the IV-curves. In addition, we analyzed the effect of interstitial vortices on these characteristics. The critical current of this device was studied as a function of the applied magnetic field, j_c(H). The function j_c(H) reveals a striking commensurability peak, in agreement with recent experimental observations. The obtained results suggest that the diamond channel, which combines the properties of pinning arrays and flux-guiding channels, can be a promising candidate for potential use in devices controlling magnetic flux motion.