Electrical conductivity and structural stability of SrCo1−xFexO3−δ

Perovskite compounds in the system of SrCo1−xFexO3−δ (x=0.2, 0.4 and 0.6) were synthesized by solid state reaction. SrCo1−xFexO3−δ shows the p-type small polaron conduction behavior. Electrical conductivity and oxygen vacancy content decrease with increase in Fe content. The incorporation of Fe increases the structural stability of SrCo1−xFexO3−δ at low temperatures, while decreasing the structural stability at high temperatures. Oxygen partial pressure has a strong influence on electrical conductivity. At low oxygen partial pressure, SrCo0.8Fe0.2O3−δ will transform from cubic to orthorhombic structure. This structure can remain in 5%H2/Ar only for a short time and then dissociates into Sr3Fe2O6.64 and Co due to the reduction of B-site elements.