Exchange coupled domain walls: Resonance in multilayers

Abstract

Exchange coupling between magnetic films can lead to an attractive force between domain walls in the separate films. The coupling between the films allows for small amplitude oscillations around the equilibrium configuration of the walls, analogous to optic and acoustic type spin wave resonance modes. Since the restoring force acts only over the length of a domain wall, this suggests the possibility of sensitive measurements of the local coupling by studying domain wall resonances. The effects of applied fields are also examined. With antiferromagnetic coupling, small static fields push the walls apart and result in different behaviors of the acoustic and optic domain wall resonances.