Ferroelectric properties of nanocrystalline barium titanate ceramics

摘要

Dense nanocrystalline BaTiO_3 ceramics with the average grain size of 20 nm obtained by spark plasma sintering were investigated. The dielectric data show a ferroelectric to paraelectric phase transition with a maximum permittivity of ≈930 at 115℃ and at 1 kHz. The polarization-reversal characteristics and the local ferroelectric switching behavior were measured; the typical piezoelectric hysteresis loops were recorded. The present results provide experimental evidence, indicating that if a critical grain size exists for ferroelectricity it is less than 20 nm for polycrystalline BaTiO_3 ceramics.