Ferroelectric and optic properties of the translucent BaTiO3 ceramics derived from nanocrystalline monolith

Polycrystalline, translucent barium titanate (BaTiO3) ceramics were successfully fabricated from partially crystallized, transparent monolithic xerogels produced by a high concentration sol-gel method using metal alkoxides. The xerogels yielded dense and translucent BaTiO3 ceramics after heat treatment at 1100degreesC for 1 h in oxygen flow, with an average grain size of about 0.5 mum and a relative sintered density of 97%. The transmittance of a ceramic (0.2 mm thick) was observed to increase almost linearly with wavelength of light, showing a transmittance of 32% at 800 nm. The dielectric constant of the ceramics at room temperature was found to be 1500, and the remanent polarization and coercive field were 2 muC/cm(2) and 5 kV/cm, respectively. The variation of transmittance for a ceramic as a function of applied electric field to examine the material's electro-optic property was also measured.