V. Z. Borodin

Domain structure and electrophysical properties of piezoelectric ceramic materials with low coercive field

Abstract The present paper reports the results of investigations of electrophysical properties and domain structure of the materials with low coercive field.

Electromechanical nonlinearity of polycrystalline ferroelectrics under resonant excitation

In this paper regularities in the change of piezoelectric and elastic properties of polycrystalline ferroelectrics are considered in their dependence on changes in the strength of the electric excitation field up to destructive levels at the main vibrational mode. A system of solid solutions from the family Pb(ZrxTi1_x)O3 + yMnO2 where 0.3 < x < 0.7, 0 < y < 3% has been our object of investigation; however, the revealed relationships have a more general character and, apparently, exist in other solid solution systems of PZT as well as, to a large extent, in polycrystalline ferroelectrics in general.

“Controlled” surface layers in BaTiO3 single crystals

In spite of the fact that the existence of surface layers in ferroelectric materials has been verified by numerous experiments, their physical nature still remains obscure.1

A Study of Evolution of Structural Parameters of PZT-Based Ferrosoft Ceramics in the Vicinity of Transition to a Paraelectric Phase

The peculiarities of structural changes of the material were investigated in the temperature range from 20 to 280°C. Electroelastic parameters: the frequency constant of radial vibrations N r and the piezoelectric modulus d 31 of the preposed sample and the poled sample being in a 1 kV/cm dc electric field were studied. It has been established that the electric field increases a temperature stability of structure of ferroelectric domains.

Effect of poling regimes on domain structure and properties of PbTiO3-based piezoceramics

Samples of piezoelectric PT-1 ceramics based on PbTiO3 modified by Ca, Nd, Bi and Mn have been studied. The poling d.c. and strong a.c. field effect on the domain structure and electrical and physical properties (eT33/e0, sE11, d33, d31, anisotropy d33/d31) has been determined. The formation of closed domain structures with laminar series of 90° domains was established for “virgin” ceramics. The orientation of 90° domain boundaries normal to the electric field direction was found to take place under the strong a.c. field. The further application of the d.c. poling field leads, mainly, to 180° domain reorientations that manifests itself in the rapid increase of piezoelectric coefficients and anisotropy under the relatively weak poling fields. It was established that the increased piezoelectric anisotropy is due to 180° and 90° domain reorientations.

Pyroelectric properties of PZT-type ferroelectric ceramics in the morphotropic phase-transition region

The temperature changes in the pyroelectric coefficient of the PZT-type materials synthesized in the morphotropic phase-transition region have been dynamically investigated under different polarization conditions. The temperature ranges of thermodynamic instability of the domain and phase structures after the “high-voltage” polarization have been revealed. The samples undergoing a phase transition into the ferroelectric state in an electric field exhibit enhanced thermal stability of domain structures.

Pyroelectric properties of low-coercive PZT-based materials

Abstract The temperature dependence of the dynamic pyroelectric coefficient at the sinusoidal thermal flow (f= 2.5; 10 and 800 Hz), the discharge currents and the dielectric permittivity (f= 1 kHz) for three groups of the low-coercive materials was studied. These materials belong to the multicomponent PZT-based systems modified with certain additives and have the Curie temperatures 215, 280 and 320°C (compositions 1, 2, 3). It has been established that in the process of heating the sample, in the region of the transition into a paraelectric phase the dynamic pyroelectric coefficient passes through two maxima between which the difference of temperatures is 27.5; 25 and 6°C for compositions 1, 2, 3, respectively. The maxima of discharge currents and the anomalies in the temperature dependence of the dielectric permittivity correspond to these maxima. A partial depolarization of the samples in the region of a low-temperature maximum of the pyroelectric coefficient and the discharge current is due to the rele...

Irreversible increase in the temperature range of existence of the orthorhombic antiferroelectric phase in PbZr1 − xTixO3 ceramics (0.02 ≤ x ≤ 0.05)

The influence of thermostating at 450°C on the dielectric and pyroelectric properties of PbZr1 − xTixO3 polarized ferroelectric specimens the range 0.02 ≤ x ≤ 0.05 has been investigated. An irreversible increase in the temperature of the ferroelectric-antiferroelectric phase transition was observed in all specimens upon their cooling after exposure to an elevated temperature for more than 1 h. The original position of the phase-transition point on the temperature scale was not recovered as a result of afterpoling upon cooling through the Curie temperature. Heating of the same specimens in the bridged mode up to 650°C with subsequent abrupt immersion in silicone oil at room temperature (hardening) is accompanied by an additional increase in the range of existence of the antiferroelectric phase from 3 to 15°C with an increase in the x concentration.

Control of the temperature hysteresis and diffuse dielectric anomaly in the temperature range of the ferroelectric-antiferroelectric phase transition in PbZr1 − xTixO3 (0.03 ≤ x ≤ 0.05) ceramics

The magnitudes of the temperature hysteresis and diffuse dielectric anomaly corresponding to the transition from the antiferroelectric phase to the ferroelectric phase in PbZr1 − xTixO3 (0.03 ≤ x ≤ 0.05) ceramics can be reversibly changed by varying the temperatures of heating and cooling in the course of thermocycling. The results obtained indicate that the antiferroelectric-ferroelectric transition in the PbZr1 − xTixO3 ceramics materials is a smeared first-order phase transition.

Peculiarities of Variation of the Dielectric Permittivity and the Pyroelectric Coefficient with Temperature in PZT-Based Ferrosoft Ceramics Modified with Different Additives of PbGeO3

ABSTRACT The temperature dependencies of the dielectric permittivity ϵ( T) the dynamic pyroelectric coefficient γd( T) and the quasi-static pyroelectric coefficient γst( T) of prepoled samples of the low-coercive materials belonging to the PZT-based multicomponent system modified with 0.5%; 1% and 2% PbGeO3 and having the Curie temperatures T c = 207, 215 and 206°C, respectively, were studied. Polarization of the samples was performed under three different conditions. It was been established that in the ϵ( T) curve one can observe a step-like variation of ϵ( T) or a slope variation at temperatures below the temperature maximum by 40–50°C. The additional low- and high-temperature maxima are observed in the γd( T) and γst( T) curves.