Interface Phenomena and Magnetic Properties of Fe/Cr Multilayers

Fe/Cr thin film multilayers were e-beam evaporated in ultra-high vacuum changing the elemental layer thickness while the Fe/Cr thickness ratio was maintained fixed to 2. The magnetic properties were correlated to the sample microstructure and morphology, as a function of the elemental layer thickness. For very low multilayer thickness, the samples are mainly constituted by particles showing both superparamagnetic and ferromagnetic behavior. By increasing the thickness of the multilayer, the superparamagnetic small particles decrease up to vanish, and the magnetic properties become antiferromagnetic. A further increase of the layer thickness determines the formation of low defective layers of pure Fe and Cr intercalated by thin regions of Fe-Cr alloy. The system becomes ferromagnetic with a significant out-of-plane tilting of the magnetization vector which determines a magnetic morphology changing from stripe-57to labyrinth-like configuration.