Diffusion-Damped Domain-Wall Motion

Abstract

The Néel model of diffusion aftereffect has been used to analyze the motion of 90° and 180° domain walls when the aftereffect mechanism is present. Instability occurs in the response of the 180° wall to step and ramps of applied magnetic fields. For a step of field, the response of the wall is delayed from the time of application of the field by a time which decreases with increasing step height. For a ramp of field in a finite sample, instability occurs when a minimum ramp slope is exceeded. These instabilities furnish a basis for the explanation of the recently reported phenomenon of ``dynamic squareness'' of the hysteresic loop.