Oxygen adsorption on a Fe/MgO(1 0 0) film: a surface magnetism investigation

The surface magnetism of an iron film grown on a MgO(1 0 0) substrate has been studied by means of spin polarized metastable de-excitation spectroscopy (SPMDS) as a function of the exposure to oxygen. The O2p states are magnetically coupled to the iron film and exhibit a splitting in energy ΔEO2p between the majority and the minority components. The behavior of ΔEO2p with oxygen exposure demonstrates that the magnetic coupling of the O2p states is strongly dependent on the local environment of the adsorbed oxygen atoms and provides a clear indication of the magnetic shielding induced by oxygen diffusion in sub-surface sites.