L. A. Shilkina

New binary systems of solid solutions based on NaNbO3

The complex investigations of new and known binary systems of solid solutions (SS), based on antiferroelectrics NaNbO3 (NN) with oxides, possessing columbite. KW-bronze, ilmenite and perovskite structure as second components: (1 - x)NN - xAIINb2O6 and (1 - x)NN - xAIITiO3 (AII - Ni. Cu, Mg, Co, Zn, Cd, Mn, Ca, Sr or Pb) have been conducted. The ferro- and piezoelectric properties with a wide range of values have been detected in all systems investigated. There are solid solutions, in which the detected values of electrophysical properties make them suitable for use in piezoelectronics.

Correlation between the microstructure of ferroelectric ceramics and their chemical and phase composition, the degree of perfection of the crystal structure and the preparation conditions

The correlation between crystallite sizes of ferroelectric ceramics and spontaneous deformation of the crystal unit cell was considered for two cases: 1) in varying concentrations of solid solutions of the systems based on NaNbO3 and PbTiO3-PbZrO3, and 2) in the individual compositions of the above systems with the crystallite size varying with the preparation conditions. It is shown that in the first case there is a reciprocal dependence between the homogeneous deformation parameter Δ characterizing the spontaneous deformation of the crystal unit cell and the crystallite sizes d. In the second case Δ varies with d.

Ferroelectric Elastance of Sodium Niobate-Lithium Niobate Solid Solutions in Relation to A -O Bond Covalence

The ferroelectric elastance of (Na, Li, A0.5′)NbO3 solid solutions was found to vary directly with the total electronegativity of elements A (EN∑A), that is, with the A-O bond covalence at B=const. Using EN∑A values and the position on the phase diagram, one can determine the solid solution parameters optimum for use in high-frequency (A′=Sr, Pb), medium-frequency (A′=Cd), and elevated-temperature (A′=Cd) devices.

The effect of space charge and crystallite size on the formation of properties of ferropiezoceramic materials

The effect is treated of the space charge field and of the crystallite size on the properties of ferroceramics of different compositions. The established qualitative correlation between the structure and electrophysical parameters, the crystallite size, and the space charge field may be useful in designing ferropiezoceramic materials for different applications and devices involving such materials.

A spread in electrophysical parameters of ferroelectric piezoelectric solid solutions and its minimization

A spread in electrophysical parameters of solid solutions based on PZT and niobium oxides is considered for a wide range of component concentration. It is shown that composition fluctuations and their associated solution imperfection cause a significant deviation of the parameters from their mean values. The fluctuations are most pronounced when the crystal structure is unstable (e.g., at morphotropic transitions and near the solubility limits of the components). The optimization of methods for solid solution preparation greatly reduces the effect of process variables on parameter reproducibility.

X-ray amd electrophisical studies of anisotropic PbTiO3-based piezoelectric ceramics

Abstract A study of structural, electrophysical and strength, parameters of anisotropic piezoelectric ceramics PCR-70 was carried out over a wide range of sintering temperatures and polarizing fields. The character of correlation between these parameters was established and described.

Obtaining, Crystal and Grain Structure, Macroresponses of the Binary System Solid Solutions (1 − x)BiFeO 3 -xPbTiO 3

We obtained almost clean samples of binary system solid solutions (1 − x)BiFeO3-xPbTiO3 (0.1 ≤ x ≤ 0.5, Δx = 0.1) using the solid-state reaction technique with further sintering according to common ceramic technology. We studied the formation patterns of their crystalline structure, microstructure, dielectric and magnetic characteristics in a wide range of temperatures and frequencies. This research suggests an explanation for the observed effects.