Theory of the nonstoichiometric 1 : 1 short-range ordering in Pb(B ' 1/3B '')O-3-type relaxor ferroelectrics

Abstract

It is known that the B-site compositional fluctuation caused by the formation of the nonstoichiometrically 1:1 ordered nanodomains is mainly responsible for the diffuse phase transition (DPT) behavior in Pb(B-1/3'B-2/3")Oa-type perovskites. A new theory of the 1:1 short-range ordering was developed to explain the observed inability of the coarsening of the ordered domains beyond nanometer scale. It was shown that both the dispersion entropy associated with the formation of negatively charged ultrafine domains and the mode of the counter-ion distribution at the domain/matrix interface played a significant role in controlling the equilibrium ordered domain size.