Extrinsic contributions to the grain size dependence of relaxor ferroelectric Pb(Mg1/3Nb2/3)O3: PbTiO3 ceramics

Abstract

This paper addresses the observed grain size with dependence of the dielectric behavior for Pb(Mg1/3Nb2/3)O3: PbTiO3 ceramics grain sizes ≥ 1.0 μm. A combined transmission electron microscopy (TEM) analysis and dielectric characterization are modeled with a modified brick wall approach. From this model, it is possible to extrapolate information such as single crystal values of dielectric maximum, Kmax, the diffuseness coefficient, δ, and the average intergranular thickness for relaxor ceramics. The calculated intergranular thickness agrees well with TEM observations, ≍2.0 nm. This semi-empirical method may be potentially useful in development work of relaxor ceramics to predict the optimized dielectric properties obtainable within microstructural restrictions.