In-plane magnetic anisotropy of stepped epitaxial Fe(001) thin films probed by x-ray magnetic circular dichroism

X-ray magnetic circular dichroism experiments were performed at the Fe L_2.3 edges on stepped epitaxial Fe thin films structured by the so-called atomic saw method. The measurements highlight a slight in-plane orbital moment anisotropy. The orbital moment is larger along the in-plane uniaxial easy magnetization axis corresponding to the crystallographic direction along which the tensile strain is relieved. This points out the link between the magnetocrystalline or magnetoelastic energy and the orbital moment anisotropy as predicted by Bruno's model. A theoretical approach performed within the tight-binding formalism corroborates the experimental results by evidencing the enhancement of the orbital moment along the more tightly bound direction.