Magnetic Anisotropy of Epitaxially Grown Fe/Mn/Co Trilayers

This paper reports a study of cubic magnetic anisotropies of bcc-Fe and bcc-Co structures in Fe/Mn/Co trilayers grown by molecular beam epitaxy onto MgO(001) substrates. Parallel ferromagnetic resonance experiments, at microwave frequency of 33.9 GHz, reveal the presence of a large fourfold magnetic anisotropy in all studied films. Two uniform resonance modes, with fourfold magnetic anisotropy in both bcc-Fe and Co layers, are excited by the microwave field in samples with Mn thicknesses of 0.83 and 0.99 nm. Films with thick Mn layer (1.16–2.20 nm) do not exhibit independent Fe and Co uniform modes, a result associated with an enhancement of the roughness at the Mn/Co interface (Fe/Mn interface roughness was estimated by
$^{57}$
Fe Mössbauer spectroscopy to be nearly constant for all films) at the Fe/Mn and Mn/Co interfaces. Magnetic anisotropy constants of bcc-Fe and bcc-Co layers of sample with 0.99 nm thick Mn layer were determined, respectively, as
$4.5\times 10^{5}$
and
$6.4\times 10^{5}\ {\rm erg/cm}^{3}$
.