Kerr-Imaged Edge-Curling Wall Effects of Narrow Magnetic Cores

Magnetic cores produced by laminating alternating magnetic/nonmagnetic layers have been shown to eliminate closure domains by linking flux vertically between magnetic layers at the edge of the film. Closure domains, which do not contribute significantly to the permeability, are undesired in patterned magnetic cores for transformers since they reduce the inductance. The inductance of narrow magnetic core transformers was found to drop with increasing frequency. Kerr images of these cores reveal partial closure domains at the edges, which explain the inductance behavior. Edge domain effects are explained based upon energy models of laminated Permalloy strips.