Experimental investigation of the interaction potential of domain walls with localized stress fields in epitaxial garnet films

Abstract

Localized stress fields which are present at the edges of evaporated layers pin domain walls. In the experiments Cr layers on epitaxial EuGaYIG films were primarily used to study these effects. Since the domain walls are pinned at the layer edges, magnetic bubbles can be pinned with their centers either inside or outside the layer. To pull off the bubbles a pulsed field gradient established by parallel conductor lines was applied. In total, five different interaction forces can be distinguished. The pinning forces are proportional to the stress in the film, i.e. the layer thickness, and independent of the layer width as long as the width exceeds the bubble diameter. For edges with a normal parallel to 〈110〉 the pinning is symmetric for both edges whereas for 〈211〉 there is an asymmetry. Most of these effects agree qualitatively with theoretical predictions by Dishman et al., which are based on perturbations of the domain wall energy through inverse magnetostriction.