Preparation, characterization and electrical properties of Ca and Sr doped LaCrO3

Abstract Perovskite structure chromites are one of the most important family of functional materials, especially useful as interconnect materials in solid oxide fuel cells (SOFCs). In this paper, the relationship of the structure, valence states of Cr, and electrical conductivity of La 0.8 Ca 0.2 CrO 3 and La 0.7 Ca 0.2 Sr 0.1 CrO 3 were studied. The samples were synthesized by solid state reaction under air or nitrogen condition, respectively. It is found that the relationship of AC conductivity with frequency is in consistent with Jonscher power law when the frequency is between 2 × 10 2 –2 × 10 6  Hz. The electrical resistivity is in line with temperature change, which means that the conduction mechanism is small polaron theory and meets Arrhenius formula. Binding energy of the Cr 2p in the compounds synthesized in air corresponded to 576.4 eV, 577.6 eV and 579.7 eV, which means the valence states of Cr are + 3, + 5 and + 6. But for the compounds synthesized in N 2 atmosphere the valence states of Cr are + 3 and + 6.