Rietveld refinement of nanocrystalline phases

Nanocrystalline phases give rise to x-ray diffraction patterns similar to those obtained for the corresponding microcrystalline system, but broadened by effect of crystallite size. Because of this similarity for the analysis of the diffraction patterns of nanostructures, the x-ray diffraction techniques developed for microcrystalline powders can be applied. One of these techniques is the refinement of the crystalline structure by the Rietveld method from the refinement lattice parameters, atom positions in the unit cell, their occupation numbers, their roof-mean-square thermal displacements, average crystallite size, average strain, and the concentration of each of the nanophases in the sample can be obtained. We describe the refinement of the crystalline structure of nanophases of MgO, TiO2, ZrO2, and KMn8O16 (C) 1997 Acta Metallurgica Inc.