Dimension and Size Effects in Ferroelectrics

Abstract

The characteristic sizes of perovskite ferroelectrics have been examined by mean-field theory in a three dimensional base, leading to a detailed evaluation of the ultimate limits of physical sizes in nanostructured ferroelectrics with the stable polar phase in situations where the influence of depolarizing field can be neglected. Consequently, the dielectric susceptibility of nanostructured ferroelectrics is also derived for a three dimensional case. The size dependencies on the phase transition temperatures of perovskite ferroelectris, such as BaTiO₃, PbTiO₃, and Pb(Zr_0.5Ti_0.5)O₃, are calculated by considering crystallographic anisotropy. In addition we have numerically evaluated the dielectric coefficient of Pb(Mg,Nb)O₃ near the Curie temperature range based on its microstructure.