2010
I. A. Lira-Hernández, F. Sánchez-De Jesús, C.A. Cortés-Escobedo and A.M. Bolarín-Miró, Crystal structure analysis of calcium-doped lanthanum manganites prepared by mechanosynthesis, Journal of the American Ceramic Society, Vol 93(10) pp. 3474-3477 (2010) Editorial John Wiley & Sons, Inc. DOI: 10.1111/j.1551-2916.2010.03872.x. ISNN: 0957-4530
Abstract
We report results of crystal structure analyses of calcium-doped lanthanum manganites, La1?xCaxMnO3, obtained by mechanosynthesis. The calcium to lanthanum ratio x was varied from 0 to 1 at increments of 0.1, allowing us to study changes in crystal structure with different degrees of calcium substitution, from LaMnO3 (x=0) to CaMnO3 (x=1). Metallic oxide precursors, Mn2O3, La2O3, and CaO, were mixed in stoichiometric proportions. The powder mixture was milled using a shaker mixer/mill. X-ray powder diffraction was used to monitor the phase transformation as a function of the milling time. Rietveld refinement was used to structurally characterize the manganites. The results show that it is possible to obtain calcium-doped lanthanum manganite by mechanosynthesis using a weight ratio of balls to powder of 12:1. After 4.5 h of milling time, the synthesis is completed; the time is independent of the calcium-doping level. However, increase of the Ca2+ content leads to a monotonic decrease of the orthorhombicity factor b/a for calcium to lanthanum ratios between 0.2 and 0.8. When the doped level is increased, a peak displacement is observed, which is associated with a distortion of the crystal structure and variation in the cell parameter. All the manganites crystallized with the same O-type orthorhombic perovskite structure as pure LaMnO3, with a space group Pnma. The structural distortion in the orthorhombic lattice with the Ca2+ content is associated with a partial oxidation of the manganese ion, the increment on vacancies, and the cationic substitution.
Mechanosynthesis and magnetic characterization of nanocrystalline manganese ferrites
MECANOSÍNTESIS DE MANGANITAS DE LANTANO: EFECTO DE LA RELACIÓN EN PESO BOLAS:POLVO
OBTENCION DE Co-27Cr-6Mo MEDIANTE ALEADO MECANICO PARA POSIBLES APLICACIONES BIOMÉDICAS
SÍNTESIS Y CARACTERIZACIÓN DE CÁTODOS DE CaxLa1-xMnO3 PARA SU APLICACIÓN EN CCOS
CARACTERIZACIÓN DE FERRITA DE MANGANESO OBTENIDA POR MECANOSÍNTESIS
Mechanosynthesis and magnetic characterization of nanocrystalline manganese ferrites
SÍNTESIS DE NiMn2O4 ASISTIDA MEDIANTE MOLIENDA DE ALTA ENERGÍA A PARTIR DE MEZCLAS DE NiO-MnO