Band Description of Variations in the Electronic Properties of SrFeO3 – δ with a Change in the Concentration of the Constituent Elements

The electronic and magnetic properties of La0.5Sr0.5Fe0.8Co0.2O3 – δ at 0.05 ≤ δ ≤ 0.35 have been studied by using the coherent potential method taking into account the strong electronic correlations in Fe t2g- and Co t2g-states. The effect of doping elements and oxygen non-stoichiometry on the electronic spectrum of SrFeO3 is considered. The introduction of La into the Sr sublattice leads to an increase in oxygen non-stoichiometry, which contributes to a growth of the accumulated charge, Q. To raise the electrical conductivity and the number of redox pairs, it is proposed to dope the Fe sublattice with Co. The solid solution La0.5Sr0.5Fe0.8Co0.2O2.95–2.65 characterized by the metallic/half-metallic type of the electronic spectrum with the redox pairs Fe4+/Fe3+, Co4+/Co3+, and Co2+/Co1+ is a promising electrode material for pseudocapacitors.