Survey of the quasi-ternary system La0.8Sr0.2MnO3 - La0.8Sr0.2CoO3 - La0.8Sr0.2FeO3

An overview on the variation of the thermal expansion, the electrical conductivity as well as nonstoichiometry of the oxide content as a function of composition within the quasi-ternary system La0.8Sr0.2MnO3-delta-La0.8Sr0.2CoO3-delta-La0.8Sr0.2FeO3-delta in air is presented. The various powders were synthesized under identical conditions. The DC electrical conductivity values of the compositions at 800 degrees C in air vary in a wide range from 15 to 1338 S cm(-1). The magnitude of electrical conductivity of the perovskites is mainly determined by the percentage of cobalt in the compositions. A similar behaviour was observed for the measured thermal expansion coefficients between room temperature and 1000 degrees C in air, increasing from 10.9 to 19.4 x 10(-6) K-1 as a function of cobalt content. Changes in the oxygen stoichiometry of the materials were characterized by temperature-programmed oxidation measurements. (c) 2007 Elsevier Ltd. All rights reserved