Alkoxide route to La0.5Sr0.5COo3 films and powders

An all-alkoxide route to films and nano-phase powders of the La0.5Sr0.5CoO3 perovskite is described. To our knowledge, this is the first purely alkoxide-based route to (La1-xSrx)CoO3, and it yields phase-pure and elementally homogeneous perovskite at 700 degrees C by heating at 2 degrees C/min. At 700 degrees C, a cubic unit cell was obtained with a(c) = 3.853A, and after further heating to 1000 degrees C, a rhombohedral cell could be indexed: a(r) = 5.417 angstrom, alpha(r) = 59.94 degrees. Ninety to 130 nm thick films of La0.5Sr0.5CoO3 were obtained by spin coating. The gel-to-oxide conversion was studied in some detail, using thermo-gravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, IR spectroscopy, and transmission electron microscope equipped with an energy-dispersive X-ray spectrometer.