摘要

Based on resistively shunted junction dynamics, we have numerically studied the depinning transition and thermally activated creep motion of vortices in two-dimensional Josephson junction arrays exposed to a weak external field with the filling factor f = 1/25. Whether the bond disorder is introduced into the system or not, a continuous depinning transition is found at zero temperature. By means of scaling analysis of the current-voltage characteristics, a non-Arrhenius creep law is observed at finite temperatures, with the existence of two universality classes depending on the strength of the bond disorder. The effects of the disorder on the critical current and critical exponents are also discussed.