Characterization of LaMeO3 (Me: Mn, Co, Fe) perovskite powders obtained by polymerizable complex method

LaMeO3 (Me: Mn, Fe and Co) perovskites, obtained by polymerizable complex method at 900 °C for 6 h with grain size of ∼80 nm, were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. The Raman active phonons in perovskites crystallized in rhombohedral symmetry—LaMnO3.15 and LaCoO3—and orthorhombic symmetry—LaFeO3—were reported. Raman spectra were excited using Ar+ laser (wavelength 514.5 nm) with various laser beam powers between 10 and 450 μW on a sample at room temperature. Raman bands were compared to those reported for other similar systems with the orthorhombic and rhombohedral Pbnm structure. The Raman spectra of LaMnO3.15 and LaCoO3 were strongly dependent on the laser beam power. Raman spectra obtained for the studied systems are related to many factors as the laser irradiation and the structure of LaMnO3.15, LaFeO3 and LaCoO3 which greatly depends on the method of preparation, particle size, oxygen content, symmetry, temperature or the oxygen partial pressure.