Theoretical wall mobility in soft ferromagnetic films

In a recent paper, calculations of wall mass as a function of velocity in thin films with parallel anisotropy were presented. The calculations, which were based on a Ritz model, showed that the mass increased with velocity. This paper presents calculations of the dependence of velocity on magnetic field, based on the same model. The results show that the wall mobility decreases with increasing field, and may eventually saturate, even though the mass remains finite. Saturation effects may be observed in films with a larger anisotropy or smaller damping than in Permalloy.