Influence of interfaces on the magnetic properties of submicron FeCo elements

We investigate the influence of interfaces on the properties of patterned elliptical elements made of epitaxial (BCC) Fe2/Co6 multilayers and polycrystalline Fe25Co75 alloy films, both containing 75 at% Co. Magnetic force microscopy shows that the formation of stable single domains in zero field is more likely in ellipses made of the alloy than of the multilayers. Magnetization measurements demonstrate considerably different behaviour of elements made of homogeneous and layered films, which imply that the magnetization reversal occurs through the formation of quasi-single domain states in the Fe25/Co75 ellipses and mainly by gradual rotation and switching in the FeCo elements.