Effects of deposition temperature and elemental layer thickness on the properties of Fe/Co multilayers grown by molecular beam epitaxy

Fe/Co multilayers were grown at different temperatures up to 200 degrees C onto MgO-(1 0 0) monocrystalline substrates, varying both the Co and Fe elemental layer thicknesses. All samples show a multilayered structure where the elemental layers are separated by a thin interfacial region which, for high-temperature growths, is constituted by an equiatomic FeCo compound. The multilayers grown at room temperature show an in-plane uniaxial magnetic anisotropy. The increase in the growing temperature determines an improvement of the sample smoothness and the appearance of two preferred in-plane orientations of the easy magnetization axis having different strengths. By increasing the Co layer thickness, the in-plane magnetic behaviour becomes isotropic, while by increasing the Fe layer thickness, an out-of-plane contribution to the magnetization vector is established, which is responsible for the appearance of a well-defined magnetic morphology constituted by stripe-like domains.