Surface magnetism of 3d monolayers on a W(1 1 0) substrate probed by X-ray magnetic circular dichroism

A theoretical investigation of the X-ray magnetic circular dichroism (XMCD) and the magnetic properties of a Fe, Co and Ni monolayer on a W(1 1 0) substrate is presented. The Ni monolayer shows very weak ferromagnetism, whereas Fe- and Co-based systems show an in-plane magnetization in agreement with experiments. The Fe and Co spin magnetic moments are reduced from their bulk value due to the surface relaxation and the hybridization with the d valence electrons of W. The orbital magnetic moments are found to be larger for the in-plane magnetization axis for all atoms. The calculated XMCD spectra reflect the anisotropy of the orbital magnetic moments.