A. V. Turik

Piezoelectricity in NaNbO3 ceramics

Piezoelectric and dielectric measurements were performed on different batches of polarized NaNbO3 ceramics. It has been established that, as a result of polarization, in these ceramics there appears a metastable ferroelectric phase existing for a long time. The presence of this phase manifests itself as a piezoelectric effect accompanied by a piezoresonance dispersion of the dielectric permittivity. The magnitudes and temperature dependencies of the piezoelectric coefficients d33 of the NaNbO3 ceramics were measured for the first time.

The role of 90° domain wall displacements in forming physical properties of perovskite ferroelectric ceramics

Abstract A proposed model which takes into account an elastic interaction between a polydomain grain and a surrounding ceramic matrix under weak external mechanical stresses has been used for evaluating a contribution from 90° domain wall displacements to piezoelectric and elastic constants of the perovskite ferroelectric ceramics. A difference between experimental and averaged constants of BaTiO3 ceramics can be explained by the estimated contribution.

Ferroelectric ceramics with a large piezoelectric anisotropy

This review concerns the experimental and theoretical publications devoted to the important problem of the large piezoelectric anisotropy in -based polarized ferroelectric ceramics.

Maxwell-Wagner relaxation in piezoactive media

Maxwell-Wagner piezoelectric, dielectric and elastic relaxations in two-layer or multilayer serial piezoactive media are considered. As distinct from the oversimple model, described in literature, we derive exact solutions by taking into account mechanical boundary conditions, transversal piezoelectric response and elastic properties of layers. We first study the Maxwell-Wagner relaxation of elastic compliances and the contribution from piezoelectric coefficients and elastic constants of two layers to the value of the relaxation time. Methods for strengthening as well as eliminating the relaxations and for the giant enhancement of dielectric permittivity are specially reviewed.

Effect of domain structure on physical properties of ferroelectrics

Abstract The elastic compliance coefficients, dielectric permittivities and piezoelectric constants of a BaTiO3 tetragonal crystal with periodically alternating layers of 180° domains were calculated. It was shown that the presence of 180° domain walls resulted in changes of a number of elastic and dielectric constants of the polydomain sample as compared with the single domain one. The propagation of elastic waves in the laminated crystal was considered. The frequency dependence of effective permittivity and the effect of domain structure on the piezoelectric behaviour of crystal were analysed.

Porous piezoelectric composites with extremely high reception parameters

The reception parameters Q33* and Qh* of modified fiber composites based on high-e33FC/c33FC, E ferroelectric piezoceramics (e33FC is the piezoelectric constant, c33FC, E is the elastic modulus) are considered as functions of the electromechanical properties and the porosity of the components. Pore configurations at which the values (Q33*)2≈(Qh*)2≈7×10−9 Pa−1 for the polymer matrices of 1-0-3 composites are much higher than for conventional ternary composites are analyzed.

Preisach model and simulation of the converse piezoelectric coefficient in ferroelectric ceramics

The electric-field dependencies of the elastic strains ξ3(E) and the converse piezoelectric coefficients d33(E) for ferroelectric ceramics of different degree of ferroelectric hardness have been measured. The observed results have been approximated by the Preisach and Rayleigh polynomials. The nonmonotonic d33(E) dependence for ferroelectric ceramics has been established. The interpretation of the observed results based on a substantially different distribution of reoriented domains over the internal and coercive electric fields in the ceramics of different degree of ferroelectric hardness is given.

On a correlation between remanent polarization and piezoelectric coefficients of perovskite-type ferroelectric ceramics

It is shown that the dependence of the piezoelectric coefficients of BaTiO3 ferroelectric ceramics on the remanent polarization is monotonic due to the influence of the domain structure of the grains. The effect of the 90° domain structure of the grains on the non-monotonic behaviour of the piezoelectric coefficients and their anisotropy in PbTiO3 ceramics is discussed. It is established that contradictions between results of some recent papers are removed by taking into account the role of the domain structure in forming the piezoelectric response of ferroelectric ceramics.

The S-type domain and twin boundaries in plate-like PbZrO3 crystals having complicated twinned structures

Four kinds of S-type domain and twin boundaries in the ferroelectric R3m and antiferroelectric Pbam phases of plate-like PbZrO3 crystals with complicated twinned structures have been described. Conditions for thermal stability of S-boundary orientations in perovskites have been formulated.

The effect of domain structure on electromechanical properties of PbTiO3,-based ferroelectrics

Abstract Dependences of the tensor components of the piezoelectric moduli, dielectric permittivities and elastic compliances on the volume concentration of 90° domains in the grains and on the temperature have been analyzed for ceramic PbTiO3. Possibilities for realization of the large piezoelectric anisotropy and its temperature variation in the crystals and ceramics of PbTiO3 have been discussed.