Effects of columnar pins on flux line dynamics

The effects of columnar pins on the flux lines in a model high-${\mathit{T}}_{\mathit{c}}$ superconductor in an applied field are studied through Monte Carlo simulations. An analytic solution for a single line case is obtained and compared with the simulation results. By introducing a tilted potential, we study simulated ‘‘I-V’’ characteristics and the results indicate a distinct scaling behavior above and below the depinning temperature. We introduce a diverging length scale measured in terms of a ‘‘retrapping length’’ to analyze self-similar behavior across the sharp depinning crossover.