Effects of cobalt substitution on the physical properties of the perovskite strontium ferrite

Structural, electronic and magnetic properties of the perovskites SrFe1-xCoxO3 (x = 0, 0.25, 0.50, 0.75 and 1) are investigated using generalized gradient approximation (GGA) and GGA with Hubbard potential within the frame work of spin-polarized density functional theory (DFT). The calculated structural parameters and geometries are consistent with the experimental results and observed decrease in the lattice constants with increase in Co concentration. The bonding nature is visualized through electron charge densities and confirms that the bond between Sr−Fe/Co is ionic, Fe/Co−O is covalent and Co−Fe is metallic. Band profiles comparison and electrical properties reveal that these compounds are metallic. It is observed that the magnetic interaction is anti-ferromagnetic at Fe rich side while ferromagnetic for Co substituted compounds. The transition of anti-ferromagnetism to ferromagnetism is explained through exchange interactions.