Vitali Yu. Topolov

Interfaces in ferroelectrics and related materials with complex domain structures

Abstract This review is devoted to studies of polydomain and/or heterophase ferroelectric crystals containing different types of interfaces, i.e. domain walls, boundaries between polydomain regions or boundaries separating single- or polydomain phases.

Evaluation of nontrivial behaviour of electromechanical coupling factors in PbTiO3-type ferroelectric ceramics

Abstract Results of evaluations of electromechanical coupling factors k * 31 , k * 33 and k * 15 in PbTiO 3 -based ferroelectric ceramics are reported. A sensibility of these parameters to changes in electromechanical constants, temperature, 90° domain structure of grains, and composition of ceramics is discussed.

On various types of piezoelectric anisotropy in polydomain boracite crystals

Abstract The paper is devoted to a determination of effective piezoelectric coefficients d3j poly and e3j poly (j = 1, 2, 3) of boracite crystals with 180° domain structure. Some features of these coefficients and their anisotropy are studied for different domain volume concentrations and/or temperatures.

A comparative analysis of electromechanical properties and their anisotropy in two-component composites with different connectivity

Abstract Some nonmonotonic concentration dependences of electromechanical constants for two-component piezoactive 2–2 and 1–3 composites are considered, Examples of significant variations of the piezoelectric anisotropy in both these composites and of a possibility of changing the sign of the elastic compliance s13 *E in the 2–2 composite are analyzed.

Domain structures and elastic phase matching in alkali halide-alkali cyanide mixed crystals

Abstract The elastic matching of complex domain (twin) structures is investigated in the cases of rhombohedral-monoclinic and monoclinic-orthorhombic phase boundaries for crystals of (KBr)1−x(KCN)x, (x≈ 0.6 … 0.7) and (KCl)1−x(KCN) (x≈ 0.8 … 0.9), respectively. The role of effective stress relaxation in the formation of the glass state at lower concentrations x is discussed.

Averaging physical constants and the problem of connection between piezoelectric properties of single-crystal and ceramic ferroelectrics

This paper is devoted to the analysis of different methods for averaging the physical constants of ferroelectric crystals as well as to the calculation of the piezoelectric coefficients d/sub ij/* and their anisotropy d/sub 33/*/|d(31)*| for PbTiO/sub 3/-type ceramics under a polarizing electric field.