Effects of Post-Deposition Annealing on the Properties of Calcium Manganese Oxide Thin Films*

We will present our results on the effects of post-deposition annealing on the structural and electrical properties of CaMnO$_{3-d}$ thin films grown by Pulsed Laser deposition. The thin films are epitaxially grown on (100) LaAlO$_{3}$ which has larger in-plane lattice parameters than that of bulk CaMnO$_{3}$, which leads to bi-axial tensile strain in the thin films. Results from our laboratory show that bi-axial tensile strain leads to low resistivity in thinner films, the resistivity increasing with increasing thickness. These results are suggestive of a coupling between strain and oxygen stoichiometry in the thin films. We have investigated the effects of post-deposition annealing in various gas ambients towards the goal of understanding the effects of relaxation and oxygen stoichiometric changes. We will present a comparison of the structural and electrical properties of as-grown and post-annealed films over a range of thicknesses.