Ferroelectric properties study for nanocgrain barium titanate ceramics

Abstract

Dense nanocrystalline BaTiO 3 ceramics with 50 nm average grain size obtained by spark plasma sintering were investigated. The dielectric data show a ferro-para phase transition with a maximum permittivity of 1602 at 120 °C and at 1 kHz. The polarization-reversal characteristics and the local ferroelectric switching behavior were measured; the typical piezoelectric hysteresis loops were recorded. The asymmetry of permanent polarization and coercive field in polarization–electric field curves were obtained and attributed to the existence of internal electric field. The present results provide experimental evidence, indicating that if a critical grain size exists for ferroelectricity it is less than 50 nm for polycrystalline BaTiO 3 ceramics.