Hydrothermal synthesis of tetragonal BaxSr(1-x)TiO3 powders

Abstract

Barium-strontium titanate (BaxSr(1-x)TiO3 or BST) powders, with x ranging from 0 to 1, were synthesized hydrothermally at 200 oC by reacting a Ti(OH)4 gel with Ba(OH)2 and Sr(OH)2. The resulting BST powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The mean particle sizes were found to be between 80 nm to 150 nm. The BST powders were found to be richer in Sr relative to the compositions of the corresponding hydrothermal solutions, indicating easier incorporation of Sr, compared to Ba, in the powders. All powders were found to be single-phase solid-solutions, and were determined to be cubic using XRD. However, Raman spectroscopy has revealed, for the first time, the presence of tetragonality in Ba-rich hydrothermal BST powders.