Numerical Study of the Anisotropic Properties of Vortex Motion in Superconducting Films with a Periodic Lattice of De ects

The anisotropic e ects on the dynamical phases of a vortex lattice driven by a uniform Lorentz force are investigated by numerical simulations. A square array of columnar defects is represented by a periodic pinning potential. We assume that ow is elastic, so that the vortex-vortex interactions can be represented by elastic forces. V-I characteristics and mean-square displacements and velocities for di erent orientations of the driving force are calculated. It is found that, for a wide range of driving force magnitude and orientation, the vortex lattice is transversely pinned in high symmetry directions of the pinning potential. In addition, the transverse pinned vortex lattice is thermally depinned at high enough temperatures.