Evolution of the electronic properties of SrFe$_{1-x-y-z}$Al$_x$Mn$_y$Co$_z$O$_3$ solid solutions depending on the composition and the degree of localization of electronic states

The genesis of the electronic spectrum in SrFe1 − xAlxO3, SrFe1 − xMnxO3, SrFe1 − xCoxO3, SrFe1 − 2xAlxCoxO3, and SrFe1 − y − zMnyCozO3 cubic solid solutions of strontium ferrite, where $0 \leqslant x \leqslant 0.15$ and $0 \leqslant y$ , $z \leqslant 0.125$ , is studied in the coherent potential approximation. The inclusion of electron correlations on 3d atoms makes it possible to reproduce the experimental content tendencies in the variation of the electronic and magnetic properties. It is shown that codoping of ferrite with cobalt and aluminum effectively increases the concentration of electron carriers and their degree of localization in SrFe1 − x − 0.15AlxCo0.15O3, which is of interest in the development of oxide thermoelectrics. Due to a relatively large contribution from delocalized states at the Fermi level, SrFe1 − y − zMnyCozO3 solid solutions with $y = z = 0.1{-} 0.12$ are promising electrode materials.