Electronic Conductivity, Seebeck Coefficient, and Defect Structure of La 1‐x Sr x FeO ₃ ( x =0.l, 0.25)

The electrical conductivity and Seebeck coefficients of La 1‐x Sr x FeO 3 ( x =0.1, 0.25) were measured as a function of oxygen partial pressure, P O2 , at T =900° to 1300°C. The electrical conduction was p type in the higher P O2 range, and n type in the lower P O2 range. The Seebeck coefficient indicated that the conduction was due to electron hopping between Fe × Fe and Fe Fe , in the higher P O2 range and electron hopping between Fe′ Fe and Fe × Fe in the lower range. The carrier concentrations were calculated from the values of electrical conductivity and Seebeck coefficient. From the P O2 dependences of the carrier concentrations, the defect structure of La 1‐x Sr x FeO 3 was determined. It was found that the electrical properties can be described by considering the imperfections Sr La , Vo , Fe Fe , and Fe′ Fe .