Structural order and magnetic anisotropy transition in Co/Fe multilayers

Abstract

Co/Fe multilayers were electron-beam evaporated in ultrahigh vacuum onto quartz substrates keeping the Co layer thickness ͑10 nm͒ constant and changing that of Fe ͑10-30 nm͒. For Fe layer thicknesses up to 24 nm, the magnetization substantially lies in the film plane and shows a uniaxial magnetic anisotropy. The coercive field measured along the easy axis is ϳ10 Oe, and the x-ray reflectivity patterns show a superlattice behavior. For a Fe layer thickness equal to 30 nm, the in-plane texture strongly decreases, the coercive field increases up to ϳ100 Oe, the magnetization direction forms an out-of-plane angle of ϳ36°and a stripe magnetic domain structure takes place. The observed in-plane anisotropy and the changing in the magnetic order as a function of the iron layer thickness is discussed and justified, assuming that the growth of the first Co layer occurs by the nucleation of ordered zones, influencing the subsequent layer order via exchange interaction.

Exchange-spring magnets based on L10-FePt ordered phase

“…Previous works on model systems [7][8][9] pointed out that a determining role in the exchange coupling between different magnetic layers is played by their nature and morphology, and by the interdiffusion phenomena occurring at the interfaces. In order to analyse these effects, Mössbauer spectroscopy has been performed on FePt/Fe bi-layers and related to the exchange coupling occurring between the soft and hard phases.…”

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

“…The increase of the soft Fe layer thickness gives rise to the initial softening of the magnetic behaviour of the multilayer. When the thickness of the soft layer becomes much higher than that of the hard one the structural disorder increases favouring an increase of the preferential sites for the domain wall pinning [12].…”

Magnetization processes in exchange-coupled nano-crystalline Fe/Co planar systems

“…In particular, cobalt films intercalated by iron layers have shown the possibility to obtain systems with a strong exchange coupling between the two ferromagnetic phases [2,3]. Another very interesting characteristic is their peculiar in-plane uniaxial magnetic anisotropy [4,5].The aim of the present work is to investigate the origin of such kind of anisotropy. With this in mind a careful characterization of structural and magnetic characteristics was performed and a correlation between microstructural and macroscopic properties was carried out.…”

“…In particular, cobalt films intercalated by iron layers have shown the possibility to obtain systems with a strong exchange coupling between the two ferromagnetic phases [2,3]. Another very interesting characteristic is their peculiar in-plane uniaxial magnetic anisotropy [4,5].…”