Microwave Electrodynamic Study on Antiferroelectric Materials in a Wide Temperature Range.

The electrodynamic properties of lead zirconate titanate ceramic solid solutions, exhibiting ferro-antiferroelectric phase transition, are investigated at microwave frequencies in a wide temperature range. Significant changes in the electrodynamic response are found, presumably associated with structural rearrangements accompanying the sequence of phase transitions between para-, ferro-, and antiferroelectric states. The phenomena observed in the experiments are considered under conditions of changing temperature and concentrations of the components; several independent measurement techniques were used for their unambiguous identification.

The Influence of the Elemental Composition, Crystal Structure, and Grain Structure of the Ferro-Piezoceramics of Various Degrees of the Ferro-Hardness on the Stability of the Polarized State.

Ferro-piezoceramic materials (FPCM) with different degrees of ferrohardness were fabricated by double solid-phase synthesis followed by the sintering technique using hot pressing method. The X-ray studies carried out in a wide temperature range showed that with increasing temperature, each of the studied FPCM undergoes a series of phase transformations, accompanied by a change in the symmetry of the unit cell. In this case, near the phase transition to the nonpolar cubic phase, in each of the FPCM, the formation of a fuzzy symmetry region is observed, which is characterized by weak distortions and temperature-time instability of the crystal structure.

Features of the Structure and Electrophysical Properties of Solid Solutions of the System (1-x-y) NaNbO-xKNbO-yCdNbO.

Ferroelectric ceramic materials based on the (1-x-y) NaNbO-xKNbO-yCdNbO system ( = 0.05-0.65, = 0.

Phase states, microstructure and dielectric characteristics of solid solutions (1 - )NaNbO - CaNbO and (1 - )NaNbO - SrNbO.

Ceramics of binary systems solid solutions (1 - )NaNbO - CaNbO and (1 - )NaNbO - SrNbO with non-isostructural extreme components were prepared by the solid-phase reactions technique with the following sintering using conventional ceramic technology. It was found that ceramics with ≤ 0.2 have a perovskite structure.

Multi-element ferroactive materials based on KNN-PZT compositions with fundamentally different physical properties.

Quasibinary section solid solutions of a four-component system of the (1-)(NaK)NbO-Pb(TiZr)O composition, based on compositions with fundamentally different physical responses (Na, K)NbO(KNN), Pb(Ti, Zr)O (PZT), have been produced by two-step solid-phase synthesis followed by sintering using conventional ceramic technology. The features of their structural formation have been revealed, a phase diagram of equilibria has been constructed, correlation relationships composition ‒ structure ‒ microstructure ‒ macroproperties have been established. Based on the measured X-ray fluorescence intensities, the concentrations of chemical elements, included in the surface composition of the samples of piezoceramic materials, have been determined.