Influence of magnetostatic interactions on the magnetization reversal of patterned magnetic elements

Abstract

The magnetization reversal in patterned thin-film arrays of elliptical submicron permalloy elements has been investigated by magnetic-force microscopy and micro-magneto-optic Kerr effect. Three different spatial arrangements of chains are considered, namely chains aligned parallel to the long axis of the ellipse, chains aligned parallel to the short axis of the ellipse, and arrays with roughly equal element-to-element spacings in both directions. Comparison of the hysteresis loops in an in-plane field perpendicular to the ellipses' long axes shows that the magnetization reversibility is highest for chains along the long axis. This is due to the nearly coherent magnetization rotation in the applied magnetic field and to the formation of a head-to-tail domain arrangement. Other arrangements, such as chains of ellipses aligned parallel to short axis, yield flux-closure domains as the applied magnetic field is changed. © 2011 American Institute of Physics.