Crystallographic and magnetic properties of Fe-Mo and Fe-W films with an artificially layered structure

Fe-Mo and Fe-W films deposited in an alternating multilayer structure by the magnetron DC-sputtering method are shown to have a compositionally modulated structure with intermixing layers thinner than two atomic layers of constituents. The crystallographic structures are amorphous for films with constituent layers thinner than 5 Å, and BCC-type crystalline for the other films. The crystalline films with small periodicities have a compositionally modulated superlattice structure, where constituent layers grow epitaxially on the (110) plane parallel to the film. The films with large periodicities have a compositionally modulated superstructure composed of periodic stacking of crystalline layers of constituents. The amorphous films are paramagnetic or ferromagnetic with small magnetization. The crystalline films are ferromagnetic with an easy magnetization direction in the film plane. The magnetizations of crystalline films are quantitatively explained by assuming one nonmagnetic Fe layer at the interface