INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
MICROSTRUCTURAL MODELLING OF CUPRIC OXIDE NANOSTRUCTURES
A. E. BIANCHI; G. PUNTE
Congreso; IV Reunión Anual de la Asociación Argentina de Cristalografía; 2008
Universidad Nacional del Sur
Nanostructured CuO powders were prepared by ball milling route. The set of X ray powder diffraction patterns obtained was analyzed using different approximations, within a Rietveld refinement approach, to characterize structure and microstructure evolution as function of ball milling time. The models employed included the assumption that samples consist of a) isotropically refined and microstrained grains, b) nanograins with some degree of shape and/or microstrain anisotropy and c) nanocrystaline grains and disordered grain boundaries (a few nanometers thick). The later model allows us to fit the patterns by inclusion of a second and almost amorphous phase, consistent with a grain boundary thickness in the range 1-2nm. The outcome of the use of the different models on the mean crystallite size and microstrain, cell parameters and super exchange path geometry is discussed.