Genesis of the electronic spectrum and magnetic properties of a high-temperature phase of nonstoichiometric strontium ferrite SrFeO$_{3-\delta}$ ($0\le\delta\le0.5$)

The genesis of the electronic spectrum and magnetic properties of a high-temperature cubic phase of SrFeO$_{3-\delta}$ with the disordered distribution of oxygen vacancies under the variation of their concentration has been studied in the coherent-potential approximation within the $\mathrm{LDA + U}$ formalism. Experimental tendencies of the fundamental electron-energy and magnetic characteristics in SrFeO$_{3-\delta}$ under the variation of oxygen nonstoichiometry within the homogeneity region, $0\le\delta\le0.5$, have been described.