Finite-size effects in dynamics of paraelectric-ferroelectric interfaces induced by latent heat transfer

A theory of the thermally induced dynamics of interphase boundaries in the case of latent heat transfer is presented for confined ferroelectrics. Two distinct types of interface motion, thermally induced, have been observed in experiment in ferroelectric perovskites: (a) slow motion usually governed by the polarization relaxation mechanism and presented by polarization kink migration, and (b) rapid motion that takes place over short periods of time and has not been sufficiently clarified. We show that latent heat transfer may cause the observed rapid motion of the interphase boundary during the phase transition temperature passage. On cooling the heat generated during the phase transition accelerates the interphase boundary The dependence of the interface velocity on the crystal size is calculated for the latent heal transfer mechanism of the interface motion. The theoretical result is in agreement with the experiment according to which the interface velocity decreases with increasing crystal size. (C) 2001 Elsevier Science B.V. All rights reserved.