First principles study of the effects of disorder in the Sr$_2$FeMoO$_6$ perovskite

Abstract

First principles calculations were done in the double perovskite $\textrm{Sr}_2\textrm{FeMoO}_6$ regarding the effects of cationic disorder and electronic correlation in the ground-state properties such as spin polarization and magnetic saturation. We used the Generalized Gradient Approximation (GGA) method including a U Hubbard term. Results with 25% of disorder, where Fe-O-Fe and Mo-O-Mo configurations frequently occur, are shown. We found that disorder breaks down the half-metallic ferromagnetic behavior. We also calculated a magnetic saturation decrease from 4.0$\mu_B$ per formula unit to 2.22$\mu_B$ in accord with neutron magnetic scattering experiments.