B-Site Stoichiometry Control of the Magnetotransport Properties of Epitaxial Sr2FeMoO6 Thin Film

The high degree of spin-polarization observed in ordered double perovskite oxide Sr2FeMoO6 at room temperature has attracted considerable interest from both fundamental and practical points of view. In this paper, we have shown a significant change in spin-polarization with a small B-site off-stoichiometry. We have demonstrated a direct correlation between the growth process, Fe:Mo (B-site) stoichiometry, and the electrical properties of half metallic Sr2FeMoO6 thin film. We have shown that varying the Fe:Mo (B-site) stoichiometry by a small atomic percent results in an order of magnitude change in resistivity and at least four times change in magnetoresistance. Theoretical calculation suggests a strong correlation between electronic structure, electronic polarization, and B-site non-stoichiometry.