Experimental evidence of magnetic anisotropy induction by superconductivity in superlattices

We present a study of Nb∕Co superlattices by ferromagnetic resonance. We find that when the superconductor enters the Meissner state, an anisotropy field around 400Oe, parallel to the applied field, appears in the ferromagnetic layers, consistent with the superconducting flux expelled from the superconducting layers. This anisotropy field is an important key to understand previous results showing that the superconductor layers modify the magnetic state of the ferromagnetic layers.