Upper critical fields and interface transparency in superconductor/ferromagnet bilayers

Proximity effect in Nb/Pd0.86Ni0.14, Nb/Cu0.46Ni0.54, and Nb/Cu0.42Ni0.58 bilayers has been studied in the presence of an external magnetic field. Upper critical field measurements, performed in parallel configuration, reveal a shift of the two-dimensional-three-dimensional crossover temperature, which we relate to the different interface transparencies of the three analyzed systems.