Temperature-induced motion of interphase boundaries in confined ferroelectrics

Abstract

Thermally induced dynamics of interphase boundaries are considered in confined ferroelectrics at a first-order phase transition. The size dependence of the temperature of the stability limit of the paraelectric phase and the phase transition temperature is calculated for a semi-infinite plate with one finite size (thickness). The velocity of the interphase boundary is presented as a function of its thickness for the thermally induced motion. The result is in agreement with the experiment on PbTiO₃. It is shown that close to the phase transition the interphase boundary should change the direction of its motion at a critical thickness of the sample, reflecting the first-order character of the ferroelectric phase transition.