Investigation of ferroelectric properties on nanocrystalline barium titanate ceramics

Abstract

Dense nanocrystalline BaTiO₃ (BT) ceramics with 50 nm average grain size obtained by spark plasma sintering were investigated. The dielectric data showed a ferro para phase transition with a maximum permittivity of 1,602 at 120ºC and at 1 kHz. The polarization reversal characteristics were measured, and the typical piezoelectric hysteresis loop was recorded. The asymmetry of permanent polarization and coercive field in polarization-electric field curves were obtained and attributed to the existence of an internal electric field. The present results provide experimental evidence, indicating that if a critical grain size exists for ferroelectricity, then it is less than 50 nm for polycrystalline BT ceramics.

Keywords

nanocrystalline BaTiO₃ (BT) ceramics, grain size, ferroelectric properties