Effect of anharmonicity of the crystal potential on ferroelectric-antiferroelectric phase transitions

The ferroelectric-antiferroelectric phase transitions in lead zirconate-titanate-based solid solutions have been considered with allowance made for anharmonicity of the crystal potential. In the phase diagram of lead zirconate-titanate, the boundary separating the regions of the ferroelectric and antiferroelectric states are shifted toward higher titanium concentrations. The calculated and experimental phase diagrams are presented for such cases.