A phenomenological potential and ferroelectric properties of BaTiO₃–CaTiO₃ solid solution

A modified phenomenological potential was constructed for BaTiO₃-CaTiO₃ solid solution single crystal based on the Landau–Devonshire theory. The Ba_1−xCa_xTiO₃ solid solution phase diagram of temperature vs concentration (T-x) is obtained and shown to perfectly agree with experimental observations. Sustained Curie temperature can be obtained by the increase of Ca concentration x, while the transition temperatures from tetragonal to orthorhombic phase, and further to rhombohedral phase decrease with increasing Ca content. In this work, spontaneous polarization and dielectric constant dependence on concentration are studied and the relationship between hydrostatic pressure and transition temperatures is established to pave the way for the generation of temperature-concentration-pressure phase diagram.