Effects of coupling disorder on the phase dynamics of superconducting clusters

We have studied the electrical transport properties of superconducting clusters, periodic arrays of Josephson-coupled superconducting islands containing only a few cells. In such small samples, variations in the coupling between adjacent islands are not averaged out and produce asymmetries in the magnetoresistance as a function of bias current and applied magnetic field. By comparing experimental results with computer simulations of the Josephson phase dynamics in the clusters, we are able to understand the origin of the observed asymmetries and obtain a quantitative estimate of the coupling disorder in our arrays.