Edge-curling-wall discontinuities and interactions with bloch walls in easy-axis permalloy

Abstract

Laminations of soft-magnetic and nonmagnetic films, which meet the criteria for the “easy-axis” state [1], have edge-curling walls instead of the triangular closure domains of single sheets. Our laser magneto-optic microscope has enabled us to image and model two types of edge-curling wall discontinuities that are induced by geometry in finite elements. One is a sectored-vortex discontinuity in a single-domain state, not previously predicted. In addition, laminates with Permalloy layers on the order of one µm thick, are usually found to be divided into easy-axis domains by 180° Bloch walls. We describe several types of interaction of a Bloch wall with an edge-curling wall. Finally we confirm, for the first time, coupled (top and bottom layers) single-domain states in two-magnetic-layer elements. © 1988 IEEE