JOSE FERNANDO QUEIRUGA REY
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Artigo IPEN-doc 11404 Synthesis of Insub(2)Osub(3) nanoparticles by thermal decomposition of a citrate gel precursor2005 - REY, J.F.Q.; PLIVELIC, T.S.; ROCHA, R.A.; TADOKORO, S.K.; TORRIANI, I.; MUCCILLO, E.N.S.Artigo IPEN-doc 13760 Primary particle size effect on phase transition in Basub(2)Insub(2)Osub(5)2008 - REY, J.F.Q.; FERREIRA, F.F.; MUCCILLO, E.N.S.The primary particle (or crystallite) size effect on the order–disorder phase transition temperature in Ba2In2O5 was investigated. Sintered specimens were prepared by solid state synthesis. Structural characterization performed by Raman spectroscopy shows that single-phase brownmillerite structure was obtained at room temperature for all prepared samples. In situ high-temperature X-ray diffraction experiments using Synchrotron radiation and electrical conductivity measurements reveal a decrease in the phase transition temperature with decreasing of the primary particle size. Lattice defects, mainly hydroxyls and nitrates, also influence the phase transition in Ba2In2O5.Artigo IPEN-doc 14071 Synthesis and characterization of spherical and narrow size distribution indium oxide nanoparticles2009 - SOUZA, E.C.C.; REY, J.F.Q.; MUCCILLO, E.N.S.This work reports the synthesis of indium oxide nanoparticles and their thermal, structural, microstructural and optical characterization. The preparation method is based on a surfactant-free room temperature soft chemistry route. Spherical indium oxide nanoparticles (about 8 nm in diameter) were obtained after thermal treatment of gels at 400 ºC for 2 h, as shown by X-ray diffraction experiments and nitrogen adsorption measurements. Transmission electron microscopy observations confirm the single-crystalline nature of the produced nanoparticles. The photoluminescence emission spectrum at room temperature shows a broad peak with onset at approximately 315 nm as a result of quantum size effect as revealed by small-angle X-ray scattering.