Nanometer‐size tin oxide particles (see Figure) with high thermal stability against particle growth have been synthesized. A low particle growth rate was achieved by doping SnO2 particles with rare earth ions during synthesis. This technology can be applied to modify the particle surface and then control growth rate and specific electric and catalyst properties, producing nanostructured materials with improved performance.

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In this letter we investigated the temperature-dependent Raman spectra of CaMn7O12 helimagnet from room temperature down to 10 K. The temperature dependence of the Raman mode parameters show remarkable anomalies for both antiferromagnetic and incommensurate transitions that this compound undergoes at low temperatures. The anomalies observed at the magnetic ordering transition indicate a spin-phonon coupling at higher-temperature magnetic transition in this material, while a magnetostrinction effect at the lower-temperature magnetic transition.

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Structural and morphological studies in pure and Ce-doped tin dioxide nanoparticles with high stability against particle growth were performed in samples, obtained using the polymeric precursor method and prepared at different annealing temperatures. A Ce-rich surface layer was used to control the particle size and stabilize SnO 2 against particle growth. The formation of this segregated layer can contribute to a decreased surface energy, acting in the driving force, or reducing the surface mobility. Only the cassiterite SnO 2 phase was observed below 1000 C and a secondary phase (CeO 2 ) was observed for the Ce-doped SnO 2 at temperatures higher than 1000 C, when de-mixing process occurs. The evolution of crystallite size, microstrain and morphology of the nanoparticles with annealing temperatures was investigated by X-ray diffraction (XRD), associated to Rietveld refinements, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). #

This paper presents and discusses some of the results of the effects of processing on rare earth-doped nanosize SnO 2 . Several relevant factors that may influence the characteristics of the final product are studied. The influence of two preparation routes and two heat-treatment conditions on the incorporation of dopants is investigated. The route whereby a soluble salt is used as the dopant source is found to provide the highest degree of dopant incorporation, even under the least favorable heat-treatment conditions.

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