Predicting the position of the morphotropic phase boundary in high temperature PbTiO3-Bi(B′B″)O3 based dielectric ceramics

Two previously unreported PbTiO3-Bi(B′B″)O3 type solid solution systems possessing a high dielectric transition Curie temperature (TC) at their morphotropic phase boundary (MPB) were investigated. Both Bi(B′B″)O3 type compounds, Bi(Mg1∕2Ti1∕2)O3 and Bi(Mg1∕2Zr1∕2)O3, possess a low tolerance factor and display extensive solid solubility with PbTiO3. Dielectric and structural properties of the MPB systems were measured. Using a relationship presented in this paper, which relates the tolerance factor and the position of the MPB in PbTiO3 based systems, the approximate compositional position of the MPB in these systems was accurately predicted prior to synthesis. It is proposed that this relationship can be used as a guide in the search for PbTiO3 based MPB systems.