Variable structural ordering in lead scandium tantalate-lead titanate materials

A phase region of variable order-disorder [VOD] has been identified in this study for compositions in the range [x = 0.0-0.075] (x: mole fraction PbTiO3). Materials from this region retain some degree of long-range ordering of B-site cations as evidenced by x-ray and electron diffraction which is enhanced with post-sintering annealing. Annealed ceramics exhibit sharp dielectric responses [K(T)] and near-normal first-order ferroelectric behavior while as-fired specimens with lesser degrees of long-range ordering show the more diffuse and dispersive characteristics of a relaxer ferroelectric.