LAUSR

In this study, SrFeO3-LaFeO3 ceramic composite was prepared from mixture of SrFeO3 and LaFeO3 powders (synthesized by solid state reactionmethod) by pressing and sintering at 1400?C for 6 h. The composite exhibits single orthorhombic structure with coexistence of SrFeO3 and LaFeO3 phases. Chemical composition and complex dielectric properties were investigated. The obtained permittivity of the SrFeO3-LaFeO3 composite is 2 to 3 times higher than that of the pure SrFeO3 or LaFeO3 perovskite samples. The observed dielectric behaviour can be explained by the localized dipolar effect and dielectric relaxation processes, arising from the presence of mixed-valence state of Fe (i.e., Fe2+/Fe3+/Fe4+ pairs) and oxygen vacancies with activation energies of 0.38 and 0.73 eV, respectively. Resistances of grain boundaries and grains were revealed by impedance spectroscopy.