Proximity effects in ferromagnet/superconductor bilayers

The local density of states (LDOS) in a ferromagnet (FM)/superconductor (SC) bilayer is obtained by using the Nambu Green's function approach. Besides the transition from the “0” state to “π” state found in the spatial variation of the LDOS in the FM, the dependence of the LDOS spectrum on the thicknesses of the FM and SC is also investigated. It is shown that the LDOS in a thin FM film in contact to the SC shows a strong superconducting feature suggesting the possible coexistence of the ferromagnetism and s-wave superconductivity induced by the proximity effects.