Phase diagram of polar states in the BaTiO3 – BaSnO3 – PbTiO3 system

The aim of the work was the synthesis and studies of ceramic samples of the ternary BaTiO₃–BaSnO₃–PbTiO₃ system, which had not been systematically studied before. Thermogravimetric, X-ray diffraction, dielectric and pyroelectric studies were performed on the synthesized samples of (1–x)BaTi_1-ySn_yO₃·xPbTiO₃ compositions with 0 ≤ y,x ≤ 1. It was found that solid solutions with the perovskite structure are formed throughout the composition region in the system. Concentration regions in which solid solutions of different symmetries are formed have been determined. The results of dielectric and pyroelectric studies show that an increase in BaSnO₃ content in samples leads to a change in their dielectric properties from ferroelectric to relaxor ferroelectric, then to properties such as those of dipole glass, and then to the properties of linear dielectrics. The research results are presented in the form of x–T phase diagrams for the entire concentration range of the (1–x)Ba(Ti_1–ySn_y)O₃·xPbTiO₃ system.