Nanostructured sodium lithium niobate and lithium niobium tantalate solid solutions obtained by controlled crystallization of glass

Transparent, nanostructured glass ceramics based on ferroelectric solid solutions of the type Na1-xLixNbO3 (in very narrow composition regions for x=0.12 and 0.93) and LiNb1-yTayO3 (y=0.5 unlimited solid solubility), can be obtained by controlled crystallization of glass. The parent glass samples were prepared by conventional melt-quenching technique. Heat-treatment of the parent glasses was performed at the various temperatures, for the same time. The glass structure evolution during the controlled crystallization was examined by FT-IR spectroscopy analysis. Crystalline phases were identified by X-ray diffraction analysis and SEM was used for microstructure characterization. Densities of the crystallized glasses were measured by Archimedean principle. The capacitance and dielectric loss tangent were measured at a frequency of 1 kHz, at the room temperature. It was found that in the all investigated systems crystallize solid solutions Na1-xLixNbO3 and LiNb1-yTayO3 in the glassy matrix, have crystal size on nanoscale (less than 100nm), which is one of requirements to get a transparent glass ceramic that could be a good ferroelectric material regarding to the measured properties. (c) 2005 Elsevier B.V. All rights reserved.