Effects of the elemental layer thickness on the properties of Fe/Co grown at 200 °C.

Thin Fe/Co multilayers were grown at 200 °C onto glass and naturally oxidized Si substrates, changing the elemental layer thickness. Onto glass substrates, the multilayers show a large in-plane uniaxialmagnetocrystalline anisotropy, which strengthens by increasing the Fe layer thickness. Onto naturally oxidized Si substrates, an appreciable out-of-plane contribution to the magnetization vector is present. This can be due to the absence in the multilayer stack of a pure-Co layer as a consequence of a large intermixing occurring at the Fe/Co interfaces, that gives rise to a structure only constituted by intercalated Fe and FeCo layers. However, by increasing the Co and Fe layer thickness, the intermixing lowers because of a change in the sample morphology and microstructure, which determines the disappearance of the out-of-plane tilting of the magnetization vector while promoting the establishing of an in-plane anisotropy.