Effects of the transverse bias field on the dynamic magnetization switching behavior

The dynamic magnetization switching behavior of a nanostructured magnetic thin film under in-plane magnetic fields is well described by a switching phase diagram composed of two critical curves, one constructed at static and the other at dynamic conditions. The coherent magnetization switching occurs at high magnetic fields above the static critical curve while the incoherent magnetization switching occurs in the region enclosed by the static and the dynamic critical curves. In the incoherent switching region, an abnormal behavior of alternating non-switching/switching that cannot be explained by using the conventional switching phase diagram occurs under a strong transverse bias field. Analytically obtained energy profiles are successfully used to explain this abnormal switching behavior, and the key factor is identified to be the energy difference between the initial state and the saddle point. More extensive and systematic results for the switching phase diagram indicate that the location of the saddle point with respect to the initial state is another important factor affecting the abnormal alternating non-switching/switching behavior.