The effect of electron reflection at the interface on the superconducting transition temperature of superimposed films

A geometry of superimposed films of two metals S and N with bulk superconducting transition temperatures Tsub(CS) and Tsub(CN) respectively (Tsub(CS)>Tsub(CN)) is considered. It is shown that the effects of reflexion can be expected to be significant in the experiments which have been performed even though films of very short mean free paths have been used in many cases. Since the experimental results have often been used to predict the strength of the electron-electron interaction in N some doubt must be cast on the values thus obtained. (Auth.)