Model calculations for the current-voltage characteristics of moving two-dimensional pancake vortex lattices in a finite stack of magnetically coupled superconducting thin films with transport current in the top layer

We consider two-dimensional (2D) pancake vortices in a stack of (Formula presented) Josephson-decoupled superconducting films in an applied magnetic induction perpendicular to the layers and transport current applied to the top layer. We assume that the pancake vortices in every layer form lattices that have the same structure and are not rotated relative to each other, though we do not require them to be in perfect registry with one another. Current-voltage characteristics are calculated, corresponding to voltage-measuring circuits attached to the top and bottom layers. The effects of both zero and nonzero uniform pinning are investigated. For small currents, the pancake lattices either remain pinned or move with the same fixed velocity. But when the surface current density in the top layer exceeds a certain value, the calculated top and bottom voltages become different from each other. We then investigate the dependence of this decoupling surface current density on the applied magnetic induction, the pinning strength, and the number of layers.