Reversible magnetization process and magnetoresistance of soft-magnetic (NiFe) hard-magnetic (CoSm) bilayers

The magnetization process and magnetoresistance were studied for soft-magnetic (NiFe)/hard-magnetic (CoSm) bilayers. In the course of the magnetization reversal, the magnetic moments in the soft magnetic layer rotate reversibly, while they are pinned by the hard magnetic layer at the interface; consequently, the direction of the magnetic moment distributes successively as in a Bloch wall. The magnetoresistance also shows a reversible change, reflecting the magnetization process. The change is explained by means of the anisotropic magnetoresistance due to angle distributed magnetic moments.