Abstract: La_0.6Sr_0.4Co_1-yFe_yO₃(y=0-1.0) fine powders were synthesized by a Glycine-Nitrate Process (GNP) method, and a perovskite-type structure with rhombohedral symmetry was certified for the powders by XRD. The electrical conductivity of La_0.6Sr_0.4CoO₃(y=0) decreased monotonously with the increase of temperature in the range from room temperature to 900℃, while the electrical conductivities of it in other n(Co)/n(Fe) ratios increased with increasting temperature and reached the maximums of 3.22×10²-1.5×10³S/cm near 600 ℃ and then decreased. The hopping of small polarons is the dominating mechanism for the electrical conduction at low temperatures. The activation energy of the small polarons hopping increased from 3.378 to 17.471 kJ/mol with the decrease of n(Co)/n(Fe) ratio. Compared with the La_0.6Sr_0.4Co_1-yFe_yO₃synthesized by a conventional solid state reaction method, those synthesized by the GNP method exhibit a higher sintering activity and electrical conductivities. The differences in the temperature of electrical conductivity maximum and activation energy between the La_0.6Sr_0.4Co_1-yFe_yO₃oxides with an identical composition synthesized by the GNP method and solid state synthesis method, respectively, are attributed to the influences of stoichiometry and microstructure on electrical transportation process.

Key words: La_0.6Sr_0.4Co_1-yFe_yO₃, Perovskite-type oxides, Glycine-nitrate process method, Mixed electronic- ionic conduction