Sub-nanosecond non-arrhenius magnetic switching in perpendicular multilayers

Measurements are presented of sub-nanosecond magnetization reversal process es of perpendicularly magnetized (CoCr/Pt) multilayers using real-time Kerr microscopy. The multilayers are placed on a ring-type recording head which is used as a sub-ns risetime field source. In the gap of the write head th e magnetic field direction changes rapidly from in-plane to out-of-plane. B y scanning the laser beam across the gap the influence of the field angle o n the reversal process is studied. The reversal time depends critically on the field angle, and faster switching occurs close to the gap (pole edge) d ue to the increase of the in-plane field. On the time scale of the study, t he rotational (non-Arrhenius) switching seems to dominate.