X-ray photoemission spectroscopy of La Ca MnO 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.