Grain size effects on the dielectric properties of BaTiO3 ceramics were characterized in the light of an effect of internal stress. Fine grained BaTiO3 with an average grain size of 1 μm exhibited higher dielectric constant, lower ferroelectric transition temperature (Tc), and lower transition energy in comparison with those of coarser grained material. For the fine grained BaTiO3, the dielectric constant decreased with increasing one-dimensional compressive pressure, whereas, for the coarse grained material, the value increased before decreasing with the pressure. The one-dimensional pressure caused an increment of Tc in both the fine and coarse grained BaTiO3. The pressure affected more significantly the coarse grained material. The relationship between these results and internal stress, and the effect of external pressure imposed on the internally stressed lattice, is discussed.

Keywords: BaTiO3, internal stress, grain size effects, dielectric properties, ferroelectric