Model for dynamic domain wall coercivity

Abstract

A lowest order theory of the dynamic coercivity of moving magnetic domain walls in insulators is developed. The power loss resulting from the production of wall localized spin waves by the interaction of the moving domain wall with anisotropy inhomogeneities is computed. It is found that at a given velocity the spin wave power production is concentrated near some particular wave-vector magnitude. The total energy loss per unit volume swept is, however, found to be generally independent of velocity in agreement with the usual definition of coercive energy loss. We find good agreement with coercivity and initial mobility data of Ju and Humphrey without the use of fitting parameters.