Pinning and thermal fluctuation effects on the two-dimensional vortex lattice: a numerical study

Within the dynamic approach we investigate numerically the influence of pin ning and thermal fluctuation effects on the motion of the two-dimensional ( 2D) vortex lattice under the action of an external driving force. At zero t emperature the critical pinning force is found to increase with increasing density of pinning centers and with decreasing of the strength of vortex-vo rtex interaction. The crossover between elastic and plastic regimes is obse rved. For the finite temperature case, three regions with different behavio r in the curve of velocity-force dependence (VFD) are observed; with increa sing the temperature, the influence of pinning effects decreases, leading t o a decrease of the critical pinning force and the restoration of the Linea r VFD. (C) 1999 Elsevier Science B.V. All rights reserved.