Dielectric and Piezoelectric Properties in the Ternary System of Pb(Zn_1/3Nb_2/3)O₃-Ba(Zn_1/3Nb_2/3)O₃-PbTiO₃

Abstract

Phase diagram of the ternary system of Pb(Zn1/3Nb2/3)O3–Ba(Zn1/3Nb2/3)O3–PbTiO3 is determined from structural and dielectric measurements. In the vicinity of Pb(Zn1/3·Nb2/3)O3, two phases of perovskite (ferroelectric) and pyrochlore (non-ferroelectric) types are coexistent. The piezoelectric active part is found near the morphotropic (rhombohedral-tetragonal) phase boundary. The most active one is obtained for the composition of 0.8Pb(Zn1/3Nb2/3)O3–0.2Pb0.7Ba0.3(Zn0.1Nb0.2Ti0.7)O3, where the planar coupling factor reaches 0.44.