Curie Temperature Behavior In Half-Metallic Ferromagnetic Double Perovskites Within The Electronic Correlation Picture

The half-metallic ferromagnetic compound Sr2FeMoO6 is considered a fundamental material to understand the role of electronic parameters controlling the half-metallic ground state and high Curie temperature in double perovskite. We present an electronic approach using the Green's function technique and the renormalization perturbation expansion method to study the thermodynamical properties of double perovskites. The model is based on a correlated electron picture with localized Fe spins and conduction electrons interacting with the local spins via a double-exchange-type mechanism. Electron correlations within the conduction band are also included in order to study the Curie temperature T-C. Our results show an increases of T-C by increasing the carrier density in La-doped Sr2FeMoO6 compounds in contrast to the case of uncorrelated itinerant electrons.