First-principles study of the electronic and magnetic properties ofSr2Fe1+xMo1−xO6

Abstract

We have investigated the electronic and magnetic properties ofSr2Fe1+xMo1−xO6 (−1≤x≤0.25), thecomposition x = 0 corresponding to the well-known double perovskite systemSr2FeMoO6, using first-principles density functional theory within the generalized gradient approximation(GGA)+U schemes. The crystal structure of the compounds has a cubic lattice forx = −1 and 0.25 while the structure of the compounds has a tetragonal lattice fromx = −0.75 to 0.0. The lattice parameters decrease slightly as the Fe content increasesand the variation of unit cell volume is linear with the compositionx. Our spin-polarized calculations give a metallic ground state for thex<0 regime and a half-metallic ground state for thex≥0 regime. The magneticstructures for x≤0 are found to be the ferromagnetic state while the magnetic structure forx = 0.25 is the ferrimagnetic state where any Fe at the Mo crystallographic site is coupledantiparallel to the Fe moments at the correct site.