Magnetic and Transport Properties of Nb/PdNi Bilayers

We investigated the superconducting proximity effect in both Nb(35 nm)/PdNi superconductor (S)-ferromagnet (F) bilayer and Nb-Nb(10 nm)/PdNi-Nb (S-SF-S) variable-thickness bridges (VTBs). In Nb(35 nm)/PdNi(d_F nm) SF bilayer, non-monotonic behavior of the superconducting transition temperature T_c was observed as a function of PdNi thickness, d_F. This non-monotonic behavior of T_c can be interpreted from the view point of damped oscillatory superconducting order parameter induced in F-layer, and the effective exchange energy E_ex extracted from the data was approximately 150 K. On the other hand, in VTBs, it was found that the superconducting critical current I_c was monotonically decreased with increasing d_F.