Numerical study of vortex pinning and plastic vortex flow in disordered Josephson junction arrays

Abstract

Pinning and plastic flow phenomena of superconducting phases of current-driven Josephson junction arrays (JJAs) in magnetic fields are studied numerically. Using the resistively shunted junction (RSJ) model of ladder-type JJAs with positional disorder, we calculate the time evolution of the phases. We focus on two characteristic threshold currents. One is the threshold current between pinned and plastic flow regimes, and the other is that between plastic flow and elastic flow regimes. Even in a strong disorder limit, it is found that the two threshold currents show weak pinning behavior against the change in the strength of a junction critical current. We discuss pinning and plastic flow phenomena on the basis of the scaling theory of pinning of density waves, emphasizing a close relationship between the RSJ and the random field XY models.