Influence of domain on grain size effects of the dielectric properties of BaTiO3 nanoceramics and nanoparticles

The dielectric property of BaTiO3 nanoparticles and nanoceramics has been studied on the basis of Ginsburg–Landau–Devonshire thermodynamic theory. In this paper, considering nanodomains, Landau coefficients have been written as a function of grain size, and the dielectric constant of the material has been calculated at a variety of temperatures and grain size. The results indicate that with decreasing grain size, the dielectric peak decreases. The two lower dielectric peaks of the orthorhombic–rhombohedral phase and tetragonal–orthorhombic phase move to higher temperature, while cubic–tetragonal phase dielectric peak moves to lower temperature. The dielectric constant of BaTiO3 ceramics decreases with decreasing grain size. The dielectric constant peak at room temperature is at the grain size which is larger than the critical grain size 17–30 nm. The calculated result is consistent with the experimental data.