Crystallization and Physical Properties of LiTaO₃ in a Reactive Glass Matrix (LiBO₂-Ta₂O₅)

Abstract

Crystallization kinetics of the glass system (100-x)LiBO₂-xTa₂O₅ (5 ≤ x ≤ 20, in molar ratio) prepared via the conventional metal-plate quenching technique have been studied by the isothermal method using differential thermal analyses (DTA). The X-ray powder diffraction (XRD) of the glasses heat-treated at 790 K/6 h confirmed the evolution of lithium tantalate (LiTaO₃) phase in the glass matrix. The value of Avrami exponent n in the Johnson-Mehl-Avrami equation was found to be greater than 3, suggesting a three dimensional growth process with an increasing number of nuclei. Scanning electron microscopy of the heat-treated samples establish the growth of the LiTaO₃ crystallites to be spherulitic. These crystallites embedded in the glass matrix were found to be pyro and ferroelectric.

Keywords:

• LiTaO₃
• crystallization
• reactive glass matrix
• LiBO₂
• dielectric constant
• ferroelectric
• pyroelectric