Abstract
The magnetization switching behavior of permalloy ring elements as a function of ring diameter and film thickness by magnetoresistance measurement is presented. The permalloy ring elements, with diameters of 2-5μm and a thickness of 14-66nm, were fabricated by electron beam lithography through a lift-off process. The switching field for the transition from the vortex state to the onion state increases with decreasing size. Furthermore, the switching field increases with increasing thickness up to a critical value of about 53-65nm, over which the switching field tends to decrease with increasing thickness. © 2004 Elsevier B.V. All rights reserved.