Critical current in Nb-Cu-Nb junctions with nonideal interfaces

We report on experimental studies of superconductor (Nb)-normal metal (Cu)-superconductor (Nb) junctions with dirty interfaces between the different materials. By using a set of simultaneously prepared samples, we investigated the thickness dependence as well as the temperature dependence of the critical currents in the junctions. Good agreement between the decay of the measured critical currents and theoretical calculations was obtained without any fitting parameters.