Solid state reaction synthesis and total electrical conductivity of La0.7Sr0.3CryMnzCo(1−y−z)O3−δ

The La0.7Sr0.3CryMnzCo(1−y−z)O3−δ samples were prepared by solid state reaction. The phases, microstructure and properties of the samples were investigated by XRD, SEM, DC four-probe method and iodometry method. The single orthorhombic phase La0.7Sr0.3CryMnzCo(1−y−z)O3−δ perovskite oxides were obtained when sintered at l350 °C for 10 h. The oxygen nonstoichiometry of the materials varied inversely with the total electronic conductivity. The sample with composition of La0.7Sr0.3Cr0.5Mn0.35 Co0.15O3−δ had the maximal total electronic conductivity and the lowest oxygen nonstoichiometry which were 22.4 S/cm and 0.040 at 850 °C, respectively. The low total electronic conductivity is related to the low relatively density of the samples directly. The activation energy of conduction changed at 550 °C, and the activation energy of conduction at high temperature (T>550 °C) was higher than that at low temperature range (T<550 °C).