Magnetic Properties of Fe/Al Multilayered Films

The structures and magnetic properties of Fe/Al multilayer thin films prepared by dc magnetron sputtering have been investigated. The crystal structure and magnetic properties of films were found to depend on the thickness ratio of the Fe and Al layers (dFe/dAl). The lattice constant increases with decreasing thickness ratio, because solid solutions of Fe and Al are formed in the interface layers. For thickness ratios below 3, the lattice constant increases discontinuously and the saturation magnetization of the iron layer decreases rapidly with decreasing thickness ratio. In this region, ordered structures such as Fe3Al seem to be formed, resulting in a decrease in Hc and an increase in the resistivity with decreasing thickness ratio. Films with layer thicknesses dFe = 18 Ã… and dAl = 6 Ã… had Hc = 1 Oe and Ms = 1200 emu/cc.