Dynamic phase diagram and orientational dependence for vortices in superconductors with periodic arrays of pinning sites

We investigate the depinning and dynamics of vortex lattices at incommensur ate field:, above the first matching field. The vortex lattice interacts wi th periodic pinning arrays for different angles of vortex driving with resp ect to the pinning lattice. We find that the optimal pinning for square arr ays of pins occurs for drives at 45 degrees with respect to the pinning lat tice. We present a dynamic phase diagram and show the evolution of these dy namic phases as a function of driving angle with respect to the pinning lat tice. (C) 2000 Elsevier Science B.V. All rights reserved.