Superconductor–ferromagnet bi-layers: a comparison of s-wave and d-wave order parameters

We study superconductor–ferromagnet bi-layers, not only for s-wave, but also for d-wave superconductors. We observe oscillations of the critical temperature when varying the thickness of the ferromagnetic layer for both s-wave and d-wave superconductors. However, for a rotated d-wave order parameter the critical temperature differs considerably from that for the unrotated case. In addition we calculate the density of states for different thicknesses of the ferromagnetic layer; the results reflect the oscillatory behaviour of the superconducting correlations.