Crystal Structure Analysis of Calcium-Doped Lanthanum Manganites Prepared by Mechanosynthesis

摘要: We report results of crystal structure analyses calcium-doped lanthanum manganites, La1−xCaxMnO3, obtained by mechanosynthesis. The calcium to ratio x was varied from 0 1 at increments 0.1, allowing us study changes in with different degrees substitution, LaMnO3 (x=0) CaMnO3 (x=1). Metallic oxide precursors, Mn2O3, La2O3, and CaO, were mixed stoichiometric proportions. powder mixture milled using a shaker mixer/mill. X-ray diffraction used monitor the phase transformation as function milling time. Rietveld refinement structurally characterize manganites. show that it is possible obtain manganite mechanosynthesis weight balls 12:1. After 4.5 h time, synthesis completed; time independent calcium-doping level. However, increase Ca2+ content leads monotonic decrease orthorhombicity factor b/a for ratios between 0.2 0.8. When doped level increased, peak displacement observed, which associated distortion variation cell parameter. All manganites crystallized same O-type orthorhombic perovskite pure LaMnO3, space group Pnma. structural lattice partial oxidation manganese ion, increment on vacancies, cationic substitution.