Preparation and characterization of ferroelectric materials of Pb1-xLaxTiO3 (PLT) composition in nanometer scale / Preparação e caracterização de materiais ferroelétricos de composição Pb1-xLaxTiO3 em escala nanométrica

AUTOR(ES)

Alexandre Mesquita

DATA DE PUBLICAÇÃO

2007

RESUMO

The main objective of this work was to obtain ferroelectric materials of Pb1-xLaxTiO3 (PLT) composition, with x = 0.10, 0.15 and 0.20, in nanometer scale in order to prepare nanostructure ceramic and thin films and characterize their structural and electric properties. The nanoparticles used to prepared ceramic samples and the solution used to prepared thin films was obtained using the conventional high temperature sintering method and by using high pressure and high temperature simultaneously. The structural modification due to particle size and lanthanum amount was followed by X-Ray diffraction (XRD), Raman spectroscopy and X-Ray absorption techniques. The transition process was followed from XRD pattern and from the Raman spectra. Samples calcined at 400 oC that were characterized as amorphous present different X-ray absorption spectra. The ceramic samples sinterized at high temperature and ambient pressure presented a microstructure (microsized grains) and electrical properties (normal ferroelectric) similar to that observed in the same samples obtained from the solid-state reaction method. On the other hand, the ceramic sample with x = 0.20 prepared at high pressure and at room temperature formed only by nanoparticles present a behavior characteristic of a relaxor ferroelectric material showing the influence of the grain size on the electrical properties of these samples.

ASSUNTO(S)

ferroelectric ceramics titanato de chumbo e lantanio nanomaterials lead lanthanium titanate cerâmicas ferroelétricas nanomateriais

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