Dynamics of bubble domains

Abstract

A simple unifying phenomenological model is developed which makes it possible to relate various motions of either bubble or stripe domains to the basic ``wall mobility'' and ``wall coercivity'' and permits the interpretation of several possible experiments in terms of these same basic quantities. A recent micromagnetics formulation of bubble‐domain dynamics, when modified, yields similar predictions and provides a definition of the bubble‐domain mobility in terms of microscopic quantities (A, K, Ms ) and the Gilbert damping parameter. It also includes domain‐wall inertial effects which are absent in the simple model. The combined theory suggests several experiments for the determination of the wall‐mobility mass and coercivity, and possible independent measurements of the Gilbert parameter. Some experimental results are presented for domains in oscillatory and pulsed field gradients. The results indicate that the new experiments, as interpreted by the present theory, are promising procedures for studying bubble‐domain materials.