Morphology evolution of BaTi5O11 nanocrystals prepared by hydrothermal method and their permittivity

BaTi5O11 nanocrystals were synthesized by a hydrothermal method. The influence of Ba/Ti molar ratio in the Ba–Ti precursors on the morphology and dielectric properties of BaTi5O11 nanocrystals was investigated. In the precursors, the Ba2+ ion concentration was decreased from 0.02 to 0.01 mol/L, and the Ti4+ ion concentration was increased from 0.08 to 0.09 mol/L. The rice-like BaTi5O11 nanocrystals were synthesized at Ba/Ti molar ratios of 20:80 and 18:82, while the flower-like BaTi5O11 nanocrystals were formed at Ba/Ti molar ratios of 15:85, 12:88 and 10:90. The pure BaTi5O11 phase was synthesized at Ba/Ti molar ratio of 18:82 in the precursor, and the material had the permittivity of 38.9 at 8 GHz, which was close to that of the bulk BaTi5O11 ceramics.