X-ray photoemission spectroscopy of La0.67Ca0.33MnO3 films

We have performed X-ray photoemission spectroscopy (XPS) on thin films of (001) and (200) oriented La0.67Ca0.33MnO3 grown on (100) and (110) SrTiO3 substrates by off-axis sputtering. The films were examined by XPS without exposing them to air. We have compared the core levels and the valence spectra between the two different orientations, as well as after the effects of air exposure and annealing in UHV. We find that the surfaces are very stable against exposure to air. Comparing the measured intensity ratios to a model for the uniform termination of the film shows the terminating layer to be MnO2 for both the (001) and (200) oriented La0.67Ca0.33MnO3 films.