Synthesis and Characterization of La1-xSrxMnO3±δ Powders Obtained by the Polymeric Precursor Route

Polycrystalline strontium-doped lanthanum manganite (LSM) powders with 0.15, 0.22, and 0.30 mol % Sr were synthesized by the polymeric precursor route using a molar ratio of 3: 1 citric acid and metal cations. The powders were characterized by Fourier transform infrared spectroscopy, thermal analysis, high-temperature X-ray diffraction to determine the crystalline perovskite phase and crystallite sizes, scanning electron microscopy for the morphological analysis, nitrogen adsorption to determine the specific surface area, and laser scattering to evaluate the particle size distribution. The LSM perovskite-type oxides containing intermediate 0.22 mol % Sr were found to exhibit a tendency to decrease in crystallite size and increase in specific surface area and, when calcined at 700-900 degrees C exhibited a pure phase of perovskite, had a crystallite size of about 17-20 nm and a specific surface area for 900 degrees C of 34.3 m(2).g(-1).