Movement of the interphase boundary inKNbO3under pressure

The study of the movement of the paraelectric-ferroelectric interphase boundary in ${\mathrm{KNbO}}_3$ under hydrostatic pressure is provided in the framework of the mean-field theory. The analytical solution for the parameters of motion of the interphase boundary is applied for the calculations of the width and velocity of the latter at different pressures. The calculations are based on the experimental data for the Curie-Weiss constant and for the parameters of the Landau-Ginzburg expression for the free energy. The response to hydrostatic pressure and the tricritical point were calculated nonempirically.