Preparation of LiTaO 3 powders at reduced temperatures by a polymerized complex method

Abstract

A polymerized complex technique was utilized to prepare LiTaO 3 at reduced temperatures, viz. 500–600°C. A methanol–citric acid (CA) solution of TaCl 5 was found to be highly resistant to ambient moisture in air. Heating of a mixed-solution of methanol, CA, ethylene glycol (EG), Li and Ta ions with a molar ratio of [Methanol]:[CA]:[EG]:[Li]:[Ta]=1:0.1:0.4:0.01:0.01 at 130°C produced a yellow transparent polymeric gel without any precipitation, which after pyrolysis at 300°C was converted to a powder precursor for LiTaO 3. The formation of pure LiTaO 3 occurred during the heat treatment of the powder precursor at temperatures higher than 500°C in static air, which was confirmed by a combined analysis using XRD and Raman scattering techniques. No X-ray diffraction and Raman spectroscopic evidence for phase separation of crystalline Li 2CO 3 and Ta 2O 5 as distinct intermediates has been obtained during the thermal decomposition of the powder precursor.