Analysis of the electronic configuration of the pulsed laser deposited La0.7Ca0.3MnO3 thin films

The electronic properties of La0.7Ca0.3MnO3−δ thin films grown by the pulsed reactive crossed beam laser ablation method are investigated. The effects of post-deposition annealing of epitaxial La0.7Ca0.3MnO3−δ thin films have been investigated using X-ray photoelectron spectroscopy (surface sensitive) and hard X-ray absorption spectroscopy (bulk sensitive). The films deposited in the high vacuum are oxygen deficient and contain mostly Mn3+. High temperature annealing in a flowing oxygen atmosphere partially changes the Mn oxidation state from +3 towards +3.4. These changes should favor a metal-like conduction and a ferromagnetic double exchange transport mechanism in the annealed thin films.