Mazur O. Kinetics of the formation of domain structures in ferroelectrics in an external electric field

The object is the kinetics of the formation of mono- and polydomain structures in ferroelectric crystals at the stage of phase transformations of the order – disorder type of the first and second kind that occur in the process of isothermal relaxation after rapid cooling under the influence of field and mechanical actions. The goal is to establish the regularities of the formation of mono- and polydomain structures in strongly non-equilibrium conditions, which are implemented at the relaxation stage after a rapid cooling of the ferroelectric sample and the determination of the influence of static and high-frequency electric fields and the comprehensive (hydrostatic) pressure on this process. Methods – analytical method of derivation of relaxation differential equations in partial derivatives, correlation analysis, qualitative analysis of differential equations with the using of concept of phase portrait, numerical Runge-Kutty algorithms. The existence of metastable polydomain asymmetric phases in the process of relaxation of the domain structure to the state of thermodynamic equilibrium is established. A square root law is derived, in which the average size of the domain grows during relaxation. It was found that at the early relaxation stage there is an incubation period of the expectation of the nuclei of ferroelectric domains. Increased probability of formation of polydomain structures while simultaneously imposing on the system of an electric field and hydrostatic pressure was established. It is shown that the formation of stable regular polydomain structures takes the threshold character depending on the parameters of the high-frequency electric field. An innovative method for the formation of quasi-one-dimensional periodic domain structures by using the rapid cooling and the high-frequency field in the form of a standing wave is proposed. Sphere – educational process, research in the field of non-equilibrium phase transformations using the proposed methods in domain engineering.