X-ray photoemission spectroscopy of La(0.67)Ca(0.33)MnO(3) films

TL;DR

This study uses X-ray photoemission spectroscopy to analyze the surface stability and termination layer of La(0.67)Ca(0.33)MnO(3) thin films grown on different substrates, revealing a stable MnO2 termination layer.

Contribution

It provides detailed surface composition analysis of La(0.67)Ca(0.33)MnO(3) films with different orientations and confirms the MnO2 termination layer through XPS measurements.

Findings

Surfaces are stable against air exposure.

Surface termination is MnO2 for both orientations.

Surface composition remains consistent after annealing.

Abstract

We have performed x-ray photoemission spectroscopy (XPS) on thin films of (001) and (200) oriented La(0.67)Ca(0.33)MnO(3) grown on (100) and (110) SrTiO(3) 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 MnO(2) for both the (001) and (200) oriented La(0.67)Ca(0.33)MnO(3) films.