Proximity effects between superconducting and magnetic films

The effect of magnetic impurities in the normal-metal side of a normal-metal-superconductor ($N-S$) "dirty" sandwich on the transition temperature of the sandwich is considered. We derive a sum rule for the kernel of the gap equation, which enables us to obtain the transition temperature in the Cooper limit. The effect of a magnetic order in the normal-metal side at temperatures close to the Curie temperature is discussed, both in the Cooper limit and in thicker films, using in the latter case Werthamer's approximation.