Repolarization of Ferroelectric Superlattices BaZrO3/BaTiO3

Abstract

With the use of the modified Sawyer-Tower scheme and Merz technique, studies were conducted on the repolarization characteristics of ferroelectric (BaZrO3/BaTiO3) superlattices on monocrystalline MgO substrate. Studies of temperature changes in the dielectric hysteresis loops indicated a sufficiently smooth decrease in spontaneous polarization compared with homogeneous barium titanate near the phase transition temperature of the superlattice. Experimental studies of switched currents have shown that the switching processes in the synthesized superlattices are implemented in two stages: activation motion (“creep” mode) and non-activation motion (slip mode). The presence of the activation switching stage and the numerical estimates show that with high probability, the movement of domain boundaries accomplishes the processes of switching in the studied superlattice. The threshold field separating the stated stages decreases with increasing temperature up to the Curie point of the superlattice, similar to the coercive field. Detection of the non-strictly exponential dependence of the switching current on the reverse field strength in the activation stage was modulated by the dependence with the power-law exponent for the applied electric field. Both techniques indicate that the studied superlattices have a small internal displacement field directed from the superlattice to the substrate.

Dielectric properties and switching processes of ferroelectric superlattices

“…These changes lead to the loss of stability of the zirconium ion in the symmetric position of the cell of the crystal lattice of barium zirconate and its displacement in the normal direction. As shown in [13][14][15][16][17], as a result of these processes, the BZ layers in the superlattice undergo a phase transition to the ferroelectric phase with the polarization vector directed perpendicular to the substrate, and the lattice BaZrO3/BaTiO3 as a whole, in accordance with research of the dielectric hysteresis * Perovskites and other Framework Structure Crystalline Materials * p 554…”

“…The main applications of ferroelectric superlattices are associated with partial (in weak fields) or complete (switching) polarization changes [13][14][15], which were carried out also by the authors of this work. This article is a synthesis of data obtained by its authors [16,17].…”

Engineering Relaxor Behavior in (BaTiO3)n/(SrTiO3)n Superlattices

“…A separate avenue for subsequent study is to extend our experiments to other superlattices such as (Ba 1-x Sr x TiO 3 ) n /(SrTiO 3 ) m , [54] (PbTiO 3 ) n /(SrTiO 3 ) m , [53,[55][56][57] (Pb 1-x Sr x TiO 3 ) n /(SrTiO 3 ) m , [55] and (BaTiO 3 ) n /(BaZrO 3 ) m . [58] Such studies, together with examinations of composition-, periodicity-, and composition-plusperiodicity-graded heterostructures, should supply a sufficient set of measurements from which to develop a quantitative theory for relaxor behavior in ferroelectric/paraelectric superlattices.…”

Influence of misfit stresses on the dielectric permeability of ferroelectric superlattices BaTiO3/BaZrO3

“…The nature of these losses is indicated by the study of switching processes in the investigated superlattice using the Merz method [19], which revealed the activation character of switching in it. According to estimates [19], this type of switching can be associated only with the presence of a domain structure [20], which requires an order of magnitude smaller field compared to switching material as a whole.…”