Effects of annealing and oxygen adsorption on the surface. Composition of thin Ni–Mg alloy films

The magnesium enrichment of thin binary alloy films was studied as a function of temperature and oxygen exposure. Several NixMg1−x alloy films (x=0.5–0.96) were prepared and studied in situ by means of X-ray photoelectron spectroscopy (XPS). Magnesium was found to segregate at the surface in agreement with the theoretical predictions. The heat of segregation ΔHs was estimated from the temperature dependence of the surface composition. Oxygen induced surface segregation of magnesium and formation of surface MgO were observed.