Oxygen adsorption on a Fe/MgO(100) film: a surface magnetism investigation

The surface magnetism of an iron film grown on a MgO(1 0 0) substrate has b een studied by means of spin polarized metastable de-excitation spectroscop y (SPMDS) as a function of the exposure to oxygen. The O-2p states are magn etically coupled to the iron film and exhibit a splitting in energy DeltaE( O2p) between the majority and the minority components. The behavior of Delt aE(O2p) with oxygen exposure demonstrates that the magnetic coupling of the O-2p states is strongly dependent on the local environment of the adsorbed oxygen atoms and provides a clear indication of the magnetic shielding ind uced by oxygen diffusion in sub-surface sites. (C) 2001 Elsevier Science B. V. All rights reserved.