Effect of random disorder on the critical behavior of Josephson junction arrays

Random percolative disorder has been introduced into 300×300 arrays of Nb-Au-Nb proximity-coupled junctions. Our measurements of dc transport properties show that large amounts of random disorder, although depressing ${\mathit{T}}_{\mathit{c}}$ and broadening the resistive transition, do not alter the scale invariance of the phase transition. These results are described by a model which rescales the Josephson lattice by the percolation correlation length. The relevance of the observations to granular thin films is discussed.