We justify the application of the theory of the kink-type motion for interphase boundaries for perovskites at first-order phase transitions and obtain a criterion for separating two mechanisms for the front motion—the latent heat transfer and the relaxation of the order parameter. Calculations of the velocity of the interphase boundary motion caused by latent heat transfer at ferroelectric phase transitions show the domination of relaxation kinetics during the ferroelectric-paraelectric phase transitions in perovskites of the ${\mathit{ABO}}_3$ type. This allows us to conclude that the dynamics of interphase boundaries in perovskites are governed by the polarization evolution. © 1996 The American Physical Society.

• Received 28 March 1996

DOI:https://doi.org/10.1103/PhysRevB.54.3055