The paper studies the nonlinear electrical response of dispersed-crystalline lead zirconate titanate powders (PbZr[Formula: see text]Ti[Formula: see text]O3, PZT) in the microwave range (8.2–12.4[Formula: see text]GHz). The main attention is paid to the influence of temperature and incident wave power on the dielectric properties of the material, especially near the morphotropic phase boundary (MPB) and phase transitions (PTs). The experiments were carried out using a waveguide measuring cell and a vector network analyzer. The results showed that the permittivity and losses of the material depend on the frequency, temperature and microwave power. A broad relaxation maximum of losses was found at ∼12[Formula: see text]GHz, which shifts to the low-frequency region upon heating. It is assumed that this maximum is due to the presence of several competing polarization mechanisms associated with the reorientation of dipoles in the B sublattice. At higher powers (>5[Formula: see text]dBm), nonlinear effects were observed, including the disappearance of the relaxation maximum, which may be due to local heating and destabilization of dipole configurations. The obtained data emphasize the importance of taking into account cooperative interactions and structural transitions when analyzing the dielectric response of PZT in the microwave range.

Samples of solid solutions of the multicomponent system [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text], of the PZT–PZN–PMN type were obtained using conventional ceramic technology. The effect of a dc bias and temperature on the structure and dielectric properties of the solid solution was studied. X-ray diffraction analysis revealed that the ceramic solid solution is characterized by the coexistence of tetragonal and pseudocubic phases in 80:20 ratio. The obtained solid solution was found to have symmetrical “butterfly” loops, which are characteristic of classical ferroelectrics and are formed only from the second study cycle. The maximum [Formula: see text] is achieved at [Formula: see text] kV/cm; the hysteresis of the [Formula: see text] [Formula: see text] dependence decreases with increasing E, becoming practically absent at [Formula: see text] [Formula: see text]kV/cm. The temperature-dependent controllable characteristics of the dielectric were studied. The data obtained at room temperature correlate well with the X-ray diffraction data. It was concluded that the obtained data could be used in the development of high-voltage devices operating based on such materials.

The paper is devoted to determination of the mechanisms of permittivity dispersion in the frequency range of (8.2–12.4) GHz in solid solutionsSolid solution of the PbZr1-TiO3 (PZT)PbZrTiO (PZT) system depending on temperature, consideringPhase transition phase transitions. Dispersed-crystalline powders of the specified composition with different molar fractions of Zr and Ti, having phase transitions betweenAntiferroelectric antiferroelectric, ferroelectric and paraelectricParaelectric states in the temperature range of (25–250) °C, were chosen as the object of study. Measurements of the reflection and transmission coefficients in the specified temperature range were carried out in a waveguide measuring cell, and the complex permittivity was calculated by the Nicolson–Ross–Weir method. Dielectric relaxationRelaxation was detected in the studied frequency range, presumably associated with vibrations of atoms in the B-sublattice. The greatest relaxation losses occur in the ferroelectric state (rhombohedral phase) at elevated temperatures, presumably due to the repolarization of the unit cells. The PbZr0.97Ti0.03O3 composition has the smallest losses, being in the antiferroelectric state at temperatures close to room temperature.

Solid solutions (SS) with a quasi-binary cross-section of a four-component system of the composition (1-x)(Na0.5K0.5)NbO3-xPb(Ti0.5Zr0.5)O3, based on compositions with fundamentally different physical responses (Na, K)NbO3 (KNN), Pb(Ti, Zr)O3 (PZT), have been prepared by a two-stage solid-phase synthesis followed by sintering using conventional ceramic technology. The influence of thermal cycling on the dielectric properties of ceramic SS with x=0.00,& mldr;,1.00 has been studied. It has been shown that thermally induced fatigue does not have a significant effect on the Curie temperature and the diffusing of the phase transition (PT) of SS containing only extreme components. It has been found that when the concentration of PZT in the studied system is varied, the epsilon '/epsilon 0(T) dependencies take on a form characteristic of ferroelectrics with a diffuse PT. When the repolarisation cycles are varied, the diffusing parameter and the Curie and Burns temperatures show a wave-like behavior. The observed effects are explained by the interaction of different defect types. A conclusion is drawn on the possible practical applications of the studied SS.

Solid solutions of system (1-x) (Na0.5K0.5)NbO3-xBiFeO(3) with 0.85 <= x <= 0.95 have been prepared by two-step solid phase synthesis followed by sintering using conventional ceramic technology. An experimental study of the crystal structure, dielectric spectra in a wide range of temperatures and frequencies of alternating electric field and magnetic phenomena was carried out. The correlation between crystal structure and macro-responses in the temperature range (300-800) K has been established. The formation of two relaxation processes of non-Debyev type in the studied solid solutions in the temperature range (529-720) K with activation energies of 0.135 eV and 0.329 eV was found.

The resultsResult of X-ray diffraction analysis, the study of their microstructureMicrostructure, and the dielectric propertiesDielectric properties of theSolid solution solid solutionsNaBiTiO 0.9Na0.5Bi0.5TiO3–0.1Na0.5K0.5NbO3 with the addition of bismuth ferriteBismuth ferrite are presented in this paper. The introduction of BiFeO3BiFeO into the system does not change the cubic symmetry of the cell at room temperature. The nature of the microstructureMicrostructure is consistent with the changes in the relative density of the ceramicsCeramics. The dependencies of the dielectric propertiesDielectric properties of the studied solid solutions indicate a combination of the relaxor nature of the objects with a Maxwell–Wagner polarization process.

Ceramic samples of solid solutions of the binary system (1−x)BiFeO3-xBaTiO3 + 2 wt.% Bi2O3 (0.29 ≤ x ≤ 0.33, Δx = 0.01) were prepared using the conventional solid-phase reaction method with and without mechanical activation. Using X-ray studies, it was found that the objects have a pseudocubic crystal structure, and limited solubility occurs in solid solutions of the studied composition, as evidenced by the presence of regions with an increased Bi or Ba content and similar cell parameters. A diffuse phase transition occurred from the FE to PE state in the temperature ranges of (650–850) K. Relaxor-like behavior and the smearing of the phase transition in the studied ceramics can be associated with the presence of non-interacting regions with an increased content of Bi or Ba, different modulation, and crystal lattice symmetry. The grain morphology and dielectric characteristics of the selected solid solutions were investigated. The highest piezoelectric coefficient, d33 = 120 pC/N, was obtained in the mechanically activated ceramics 0.71BiFeO3-0.29BaTiO3 + 2 wt.% Bi2O3.

The regularities of the influence of mechanical activation procedures on the processes of phase formation, formation of crystalline and grain structures, and electrophysical properties of ferro-piezoelectric material based on a three-component system of solid solutions (1-x) Pb(Ti0.47Zr0.53)O3-xPb(Nb2/3Zn1/3)O3 doped 1.5 mas. % Mn2O3 with x = 0.15 have been established. The durations of mechanical activation that give a high density of ceramic, its best dielectric, piezoelectric and ferroelastic parameters have been determined. It has been shown that the dependence of these parameters on the duration of mechanical activation confirms the known correlation relationship "elemental composition-internal structure (crystalline, grain, domain & mldr;) - macro-responses" realized in materials with special electrical properties (ferroelectrics). It should be noted that the extreme values of all the presented characteristics are realized under such technological regulations that ensure the extreme nature of the parameters of the internal structure of objects. In this respect, the best piezoelectric characteristics and mechanical quality are possessed by the studied ceramics mechanically activated for (10-15) minutes. A conclusion is drawn on the expediency of using the obtained data in the development of similar materials and devices based on them.

Solid solutions of the binary systems based on lithium metaniobate of the form LiNbO3 - A2+TiO3 (A2+ - Co, Ni, Cu) were prepared using optimal technology and studied. The solubility boundaries of the components, the symmetry and parameters of the unit cells of the formed solid solutions were determined by X-ray diffraction. Two groups of systems were distinguished: with the formation of continuous series of the solid solutions and with limited solubility of the components. The developed piezoceramic materials can be used to create piezoelectric elements for high-frequency measuring equipment designed to control objects that experience extreme external influences.

Твердофазным синтезом с последующим спеканием по обычной керамической технологии получены образцы твердых растворов трехкомпонентной системы (1-x)Pb(Ti0.5Zr0.5)O3- x/2CdNb2O6 с x=0.025÷0.100, Δx=0.025. Исследованы кристаллическая структура, микроструктура, электрофизичские и теплофизические свойства этих керамик. Показано, что все исследованные твердые растворы можно разделить на две группы (с x=0.025 и с x>0.025), характеризующиеся различными особенностями изменения свойств при вариациях внешних воздействий.Это, вероятно, обусловлено переходом отструктуры типа перовскита с тетрагональной (Т) элементарной ячейкой к неоднородным ТР, состоящим из серии Т- фаз с близкими параметрами ячейки. Сделано заключение о целесообразности использования полученных данных при разработке подобных материалов устройств на их основе.

The solid solutions of the (1-x)Na[Formula: see text]Bi[Formula: see text]TiO3-xNa[Formula: see text]K[Formula: see text]NbO3 system were produced by the conventional ceramic technology using mechanical activation of the synthesized product. It was found that in the (1-x)Na[Formula: see text]Bi[Formula: see text]TiO3-xNa[Formula: see text]K[Formula: see text]NbO3 system at room temperature, a number of morphotropic phase transitions occur: rhombohedral → cubic → tetragonal → monoclinic phases. The introduction of a small amount of Na[Formula: see text]K[Formula: see text]NbO3 leads to an increase in the temperature stability of the dielectric properties of ceramics. A change in the relaxor properties of the solid solutions of the (1-x)Na[Formula: see text]Bi[Formula: see text]TiO3-xNa[Formula: see text]K[Formula: see text]NbO3 system was shown. The increase in energy density and energy efficiency was found at additive 10[Formula: see text]mol.% of Na[Formula: see text]K[Formula: see text]NbO3.

Materials, based on strontium titanate, have many applications in microwave technology. The main methods for achieving target characteristics when developing such materials are modification of the composition and creation of low-dimensional structures. Due to the high cost of single crystals of suitable shape for measuring electrical parameters using standard methods, ceramics and composites are being considered as an alternative. The work proposes to use a set of simpler measurement techniques that allow for a primary analysis of the microwave response of single-crystal materials and simplify further modeling and calculations. The results of calculating the resonance response of a model single-crystal sample of strontium titanate are presented. The influence of the features of measurement techniques on the final results is analyzed. Conclusions are drawn about the feasibility of conducting comprehensive studies using various techniques. The results obtained will help in further calculations and modeling of the electrical parameters of single-crystal samples of functional materials.

Using the method of two-stage solid-phase synthesis, involving mechanical activation of the synthesized powders and subsequent sintering using conventional ceramic technology, ferroelectric multicomponent solid solutions, based on the PZT system, were produced, characterized by fairly high Curie temperatures and pyroelectric coefficients, high coefficients of pyroelectric sensitivity and resistance to vibration interference, which makes it possible to classify them as pyroelectric materials, are promising for use as working elements of sensors for pyroelectric receivers of radiant (thermal) energy.

The paper presents the results of a study of the microwave absorption properties of ceramic materials based on bismuth ferrite containing rare earth elements, as well as systems of solid solutions ([Formula: see text])BiFeO 3 –xPbFe[Formula: see text]Nb[Formula: see text]O 3 in a wide range of component concentrations. The methodology for measuring and calculating the parameters of samples of the materials under study is described. The influence of structural and microstructural factors on the average and maximum level of microwave absorption of the materials under study in a wide frequency range is analyzed. A comparison of the microwave absorbing properties of these materials with industrial absorbers has been carried out, and prospects for application in microwave technology have been shown.

The results of the crystal structure studies by method X-ray diffraction and Mossbauer effect and the microstructure analysis by high resolution transmission electron microscopy of solid solutions of the (1-x)PbFe1/2Nb1/ 2 O 3- x PbFe 2/3 W 1/3 O 3 system are presented. X-ray diffraction and transmission electron microscopy studies at room temperature reveal the presence of extended planar defects- crystallographic shift planes in the crystal structure of the solid solutions (1x )Pb(Fe 1/2 Nb 1/2 )O 3- x Pb(Fe 2/3 W 1/3 )O 3 system. The structure of the solid solutions (1x )Pb(Fe 1/2 Nb 1/2 )O 3- x Pb(Fe 2/3 W 1/3 )O 3 system is demonstrated to comprise regions of disparate chemical composition, as evidenced by a range of techniques.

We studied solid solutions of the system (1-x)PbFe1/2Nb1/2O3 - xPbFe(2/3)W(1/3)O(3) using X-ray and Neuron diffraction, and M & ouml;ssbauer spectroscopy. To obtain ceramics, we used the method of two-stage solid-phase synthesis and sintering according to the conventional ceramic technology. Pure solid solutions of the (1-x)PbFe1/2Nb1/2O3-xPbFe(2/3)W(1/3)O(3) system were obtained. A deviation of the unit cell parameters from the Vegard rule was revealed, which indicates stratification of the structure into microregions differing in composition. The introduction of PbFe2/3W1/3O3 into the system led to partial ordering (clustering) of cations in the B position. An increase in magnetic moment with growing amount of PbFe2/3W1/3O3 was shown.

Using conventional ceramic technology, solid solutions (SS) of the system (1 – x)(Na0.5K0.5)NbO3 – xBiFeO3 with x = 0.05, 0.20, 0.55, 0.95 were obtained by solid phase synthesis in two stages. It has been established that the structure of the studied solid solutions critically depends on technological regulations: solid solutions close in composition to (Na0.5K0.5)NbO3 are characterized by the highest sintering temperatures, low relative densities and their discrepancy in trial and experimental samples at one and the same temperature; and those close in composition to BiFeO3 are characterized by low sintering temperatures, high relative densities and practically identical relative densities of trial and experimental samples. Two phase transitions have been identified: (i) in fact the decomposition of SS, takes place in the interval 0.00 < x < 0.05, (ii) transition from the C-phase to the Rh-phase occurs in the interval 0.55 < x < 0.95.

The paper demonstrates the results of a study of lead-free solid solutions of BaTi1-xZrxO3 modified with AgNbO3. Solid solutions, obtained by two-stage solid-phase synthesis, have high density, and show signs of coexistence of several crystallographic phases. Widely blurred maxima are observed on the dependencies of the dielectric constant, which may be a consequence of the close temperatures of the phase transitions in BaTi1-xZrxO3 and AgNbO3. Low concentrations of AgNbO3 lead to a significant change in the shape of the dielectric hysteresis loops compared to BaTi1-xZrxO3. At low concentrations of AgNbO3, optimal energy harvesting conditions are achieved, showing 0.085 J · cm−3 and 77