Structural features and high-temperature properties of SrFe1 − xSixO3 − δ

• The maximal solubility of silicon x = 0.25 is observed in SrFe1 − xSixO3 − δ at 1300 °C.
• Silicon cations trap oxygen vacancies and reduce ion conductivity.
• The doping is accompanied with reduction of oxygen content variations.
• The doping results in decreased thermal expansion in air.

The perovskite-like oxide series SrFe1 − xSixO3 − δ, where x = 0.05, 0.10, 0.15, 0.20, 0.25 and 0.30, was obtained by the solid state synthesis at 1300 °С. The maximal solubility of silicon is found to be near xm = 0.25. The observed increase of the cubic lattice parameter with silicon content is shown to be mainly related with reduction of iron cations. The silicon doping is also accompanied with the decrease of oxygen homogeneous range and expansion of SrFe1 − xSixO3 − δ ceramics at heating in air. It is shown that silicon dopants influence rather weakly the electron–hole contribution to the total conductivity while oxygen ion component undergoes a strong decline. The dependence of the ion conductivity from silicon content can satisfactorily be explained in frameworks of the model with oxygen vacancies trapped near silicon dopants.