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In flux-grown (1-x)NaNbO3-(x)Gd⅓NbO3 solid solution crystals a diffusion of the dielectric permittivity ε maximum grows with x and increases dramatically when x exceeds a threshold value x0 ≈ 0.1. Optical studies by the rotating-polarizer method show that Gd-doping results in a very small mean size of twins and the distribution of the birefringence image becomes very messy. In the x < x0 range the changes of lattice parameters and birefringence corresponding to the ε(T) anomaly were revealed. The results obtained are in line with the assumption that phase transition diffusion in NaNbO3 is a result of the local strains stemmed from the impurities. [ABSTRACT FROM AUTHOR]

Deals with a study which determined the properties of nonstoichiometric sodium niobate. Background to the study; Analysis of the X-ray diffraction data; Conclusions.

Abstract: The physical properties of PZT (PbTi x Zr1−x O3, 0.0≤x≤1.0) ceramics were studied in broad ranges of constant and alternating electric field strengths (0kV/cm≤E≤30kV/cm). Dielectric, piezoelectric and elastic parameters of the solid solutions at room temperature were investigated. The results can be helpful to develop of PZT based materials for use in various high-voltage devices and bend components such as varactors, phase shifters, etc. [Copyright &y& Elsevier]

Abstract: Based on high temperature x-ray diffraction studies of the PZT system (PbTi x Zr1−x O3, 0.0≤x≤1.0) the complete x-T phase diagram of solid solutions is built, which exhibits peculiar properties due to the real structure of ceramics: [-] irregularity of the phase transition line to the paraelectric state, which is more pronounced in the rhombohedral–tetragonal transition region; [-] appearance of intermediate “region of indistinct symmetry” at 0.2≤x≤1.0, which forestalls the transition to the non-polar cubic phase at temperature increase; [-] formation of two morphotropic regions: contracting (rhombic–rhombohedral) and expanding (rhombohedral–tetragonal) at temperature increase; [-] richness of single-symmetry phase diagram fragments by regions of coexistence of phase states. The homogeneity regions of the real solid solutions contain phase-boundary lines of a new type evidencing of intraphase transitions prevailing in the rhombohedral phase, which show up in the presence of two and more different cell values (preserving the global crystal lattice symmetry). [Copyright &y& Elsevier]

Abstract: The sequence of phase transformations in the ceramic system PbTi x Zr1−x O3 (0≤x≤1.0) is determined and the real phase diagram of solid solutions is built. The observed periodicity of phase formation processes in the rhombohedral and tetragonal regions is explained by the real (defective) structure of PZT system ceramics, which is in many respects related to the variable valence of Ti ions and, as a result, to formation, accumulation, and ordering of point defects (oxygen vacancies) and their elimination by crystallographic shifts. The obtained results are useful in interpretation of the macroscopic properties of ceramics based on the PZT system. [Copyright &y& Elsevier]

Abstract: Solid solution (SS) ceramics of the PZT (PbTi x Zr1−x O3, 0≤x≤1.0) system were studied in broad temperature (10≤T≤1000K) and electric field frequency (10−2≤f≤107 Hz) ranges. Several groups of SS were distinguished, which differ by nonmonotonic behavior of dielectric parameters in the cryogenic temperature range and at Т>300K, which results both from the defective state and from the polymorphism of SS. A conclusion is made on the expediency of use of the obtained data during the application of materials based on the PZT system in the broad range of external actions. [Copyright &y& Elsevier]

Abstract: Single crystals of La1−x Bi x Mn α O3±β and La1−x−y Bi x A y Mn α O3±β (A=Ba, Pb) are grown, their crystal and electron structure is studied. Relative Mn3+/Mn4+ abundance in each single crystal is determined via fitting experimental Mn2p-spectra with weighted superposition of theoretical spectra of tri- and quadrivalent Mn, and, for barium-free samples, from energy splitting of the Mn3s-spectra components. Strong heterogeneousness of the crystals both in elemental composition and crystal structure is discovered. It is shown that the heterogeneousness displays itself in various oxygenic environments around Mn atoms which give rise to the appearance of Mn4+ ions. A simple model is proposed that allows understanding the nature of the appearance of Mn4+ ions in single crystals of lanthanum–bismuth manganites. [Copyright &y& Elsevier]

Abstract: This work is concerned with the specific features of sintering of solid solutions of the PZT system (PbZr1−x Ti x O3, 0.0≤x≤1.0) depending on composition. The microstructure of the solid-solution ceramics has been found to be a fairly homogeneous, mosaic, sufficiently close packing of isometric crystallites with a range of section from 3 to 11μm, but there exists a number of special features related to the component and phase composition of the objects. It has been found that the changes in multifractal parameters of grain structure of these ceramics reflect with high sensitivity the processes of phase transformations in the solid solutions. The obtained results are useful in developing piezoelectric materials based on the PZT system. [Copyright &y& Elsevier]