Magnetic hardening in SmCo\u3csub\u3ex\u3c/sub\u3e–Co multilayers and nanocomposites

SmCox–Co (x = 3.5, 4, and 5) nanostructured multilayers have been prepared by dc and rf sputtering. Magnetic hardening has been found in the as-deposited thin films. The effects of the Co and hard-phase layer thicknesses and the effect of the Cr underlayer have been studied. Further magnetic hardening has been achieved by heat treating the samples. A remarkable increase of the coercivity has been obtained in the nanocomposite films, with coercive force up to 40 kOe. Transmission electron microscopy, atomic force microscopy, and magnetic force microscopy observations have been performed to understand the nanostructure and the domain structure