Kerr microscopy studies of microwave assisted switching

We study microwave assisted magnetization reversal of elliptical Ni81Fe19 thin film elements employing Kerr microscopy. A microwave field is applied along the short axis of the element and orthogonally to a quasistatic magnetic field, which is parallel to the long axis of the element. The reversal process is characterized by the formation of a complex multidomain structure. We demonstrate that the reversal process in total is compressed by applying a sufficiently high microwave field, which assists to overcome the effective energy barrier of the domain nucleation, and thus reduces the coercive field.