Study on valence state and electrical conductivity of La1−xCaxCrO3 Original Research Article

La1−xCaxCrO3 (x=0.0–0.5) samples were prepared by the sol-gel method. The sintering temperature of the samples can decrease to 1573 K. The crystal structures of La1−xCaxCrO3 at room temperature all are of the orthorhombic perovskite GdFeO3-type. XPS analysis indicates that the chromium ions are in a mixed valence state. The introduction of Ca2+ into the lattice is compensated by the oxidation of Cr3+ to Cr6+. With increasing x, the amount of Cr6+ increases. The presence of Cr6+ is one of the key factors affecting the electrical conductivity of La1−xCaxCrO3.