Ab Initio study of half-metallic feature and electronic structure of A2FeMoO6 (A=Ba,Ca) magnetic system

Abstract

We report several ab initio calculations performed over the A 2 FeMoO 6 (A=Ba, Ca) double perovskite. Results show that it is an insulator for the spin up orientation and conductor for the other one. We investigate the electronic structure of A 2 FeMoO 6 by means calculations of density of states for both spin orientations, based on the Density Functional Theory and the Linearized Augmented Plane Waves method. For the exchange correlation potential we chose the Generalized Gradient Approximation since this potential consider the difference between the electronic densities for the two distinct spin orientations from the beginning. The density of states is calculated by the histogram method and the position of the Fermi level is found by integrating over the density of states for both spin orientations. With the calculated densities of states, the half metallic properties of these compounds can be observed with the position of the Fermi level. Our results are in agreement of the Sarma's methodology, who considers a new mechanism for the magnetic interactions responsible for the magnetism on the A 2 FeMoO 6 family. We also calculate the cell dimensions that minimize the total energy for each configuration using the Murnaghan equation state.

First-Principle Studies of Ferrimagnetic Double Perovskite Ca2FeMoO6 Compound

“…Half-metallic ground state with an energy gap in the majority spin channel and strongly hybridized bands at the Fermi level for the minority spin component using the SIC-LSD approach was obtained for double Ca 2 FeMoO 6 perovskites [24,25]. Bonilla et al [26] from their study attributed the half-metallic character in Ca 2 FeMoO 6 compound to the spin down t 2g states of the Fe 3d and Mo 4d states, which is responsible for the conductivity. The insulating behavior of the spin up configuration in Ca 2 FeMoO 6 compound was attributed to the e g states.…”