OXIDATION OF RARE-EARTH MAGNESIUM INTERFACES

A photoemission study of formation and oxidation of rare earth/magnesium interfaces is presented. Our results indicate that a thin, rare earth rich amorphous surface alloy forms when the rare earths Ce or Pr are evaporated onto a magnesium substrate at room temperature. When these systems subsequently were exposed to oxygen, only weakly enhanced substrate oxidation was observed. This differs from previous observations on e.g., Al and Ta substrates, where strongly enhanced oxidation was seen. Differences in the Mg and Al systems are though to be related to different oxide structures.