In this paper, we report the successful growth of 0.5BiFeO3–0.5PbFe0.5Nb0.5O3/SrTiO3/Si(001) heterostructure using RF-cathode sputtering in an oxygen atmosphere. The deposited films have been investigated by X-ray diffractometry and spectroscopic ellipsometry (SE). 0.5BiFeO3–0.5PbFe0.5Nb0.5O3 films on silicon substrates with a strontium titanate buffer layer are single-phase, polycrystalline with a texture in the 001 direction. The unit cell parameters calculated in the tetragonal approximation were c = 4.005 ± 0.001 Å; a = 3.995 ± 0.001 Å. The presence in the films of small unit cell deformation arising from different unit cells parameters of the film and substrate is observed. Dielectric properties and capacitance-voltage characteristics have been measured. The ellipsometric parameters have been obtained.In this paper, we report the successful growth of 0.5BiFeO3–0.5PbFe0.5Nb0.5O3/SrTiO3/Si(001) heterostructure using RF-cathode sputtering in an oxygen atmosphere. The deposited films have been investigated by X-ray diffractometry and spectroscopic ellipsometry (SE). 0.5BiFeO3–0.5PbFe0.5Nb0.5O3 films on silicon substrates with a strontium titanate buffer layer are single-phase, polycrystalline with a texture in the 001 direction. The unit cell parameters calculated in the tetragonal approximation were c = 4.005 ± 0.001 Å; a = 3.995 ± 0.001 Å. The presence in the films of small unit cell deformation arising from different unit cells parameters of the film and substrate is observed. Dielectric properties and capacitance-voltage characteristics have been measured. The ellipsometric parameters have been obtained.

The properties studying results of ceramics based on strontium, calcium and sodium niobates, which vary from the conditions of synthesis, sintering, and mechanical processing, are presented. The evolution of the grain structure of objects is traced depending on their phase filling during concentration changes in the composition and thermodynamic prehistory (preparation conditions).The properties studying results of ceramics based on strontium, calcium and sodium niobates, which vary from the conditions of synthesis, sintering, and mechanical processing, are presented. The evolution of the grain structure of objects is traced depending on their phase filling during concentration changes in the composition and thermodynamic prehistory (preparation conditions).

Ceramic samples of BiFeO3-based perovskite solid solutions with the highly ordered complex perovskites PbFe1/2Sb1/2O3(PFS) and SrFe1/2Sb1/2O3 (SFS) were obtained using high-pressure synthesis at 4–6 GPa. Mössbauer studies revealed that BiFeO3-SFS compositions are characterized by a larger compositional inhomogeneity as compared to BiFeO3-PFS ones. In line with this result, concentration dependence of the magnetic phase transition temperature TN for BiFeO3-SFS compositions is close to the TN(x) dependence for BiFeO3solid solution with disordered perovskite PbFe1/2Nb1/2O3(PFN). In contrast to this TN(x) dependence for BiFeO3-PFS compositions nicely follows the theoretical TN(x) dependence calculated for the case of the ordered distribution of Fe3+ and non-magnetic Sb5+ ions in the lattice (chemical ordering).Ceramic samples of BiFeO3-based perovskite solid solutions with the highly ordered complex perovskites PbFe1/2Sb1/2O3(PFS) and SrFe1/2Sb1/2O3 (SFS) were obtained using high-pressure synthesis at 4–6 GPa. Mössbauer studies revealed that BiFeO3-SFS compositions are characterized by a larger compositional inhomogeneity as compared to BiFeO3-PFS ones. In line with this result, concentration dependence of the magnetic phase transition temperature TN for BiFeO3-SFS compositions is close to the TN(x) dependence for BiFeO3solid solution with disordered perovskite PbFe1/2Nb1/2O3(PFN). In contrast to this TN(x) dependence for BiFeO3-PFS compositions nicely follows the theoretical TN(x) dependence calculated for the case of the ordered distribution of Fe3+ and non-magnetic Sb5+ ions in the lattice (chemical ordering).

This work presents the results of studying the electrophysical properties of the YCu0.15Mn0.85O3 solid solution in the range of temperatures of T = 26–400∘C and frequency range of f = 102–105 Hz. A model description of the revealed dispersion of dielectric parameters in the material is made. The nonclassical modified Havriliak–Negami model written for complex electrical conductivity was used as an approximation model. It is shown that the application of this model almost exactly describes the frequency behavior of the dielectric constant 𝜀′/𝜀0( f), the dielectric loss tangent tgδ( f) as well as the real and imaginary parts of complex conductivity γ′( f) and γ′′( f). The results of this work are an important step in identifying the opportunities and understanding the applications of this model.This work presents the results of studying the electrophysical properties of the YCu0.15Mn0.85O3 solid solution in the range of temperatures of T = 26–400∘C and frequency range of f = 102–105 Hz. A model description of the revealed dispersion of dielectric parameters in the material is made. The nonclassical modified Havriliak–Negami model written for complex electrical conductivity was used as an approximation model. It is shown that the application of this model almost exactly describes the frequency behavior of the dielectric constant 𝜀′/𝜀0( f), the dielectric loss tangent tgδ( f) as well as the real and imaginary parts of complex conductivity γ′( f) and γ′′( f). The results of this work are an important step in identifying the opportunities and understanding the applications of this model.

Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements. ZnO nanorod arrays being good piezoelectric materials possess large surface area, which provides extra benefits for chemisorption and photodetection. Highly oriented nanorod arrays are typically prepared onto highly crystalline substrates, whereas the nanorods growth onto metal contacts meets significant technological difficulties. In this paper, we report on carbothermal, electrochemical, and hydrothermal techniques of ZnO nanorod arrays synthesis on metal contacts. The optical and structural properties of the obtained nanorods were studied using scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, and luminescence spectroscopy. A reliable technique was developed for obtaining ohmic contact with the grown nanorods. I–U curves of prepared contact were studied. Carbothermal synthesis made it possible to obtain the most crystallinely perfect, homogeneous, and dense arrays of nanorods and control the concentration of point defects by changing the synthesis parameters over a wide range. The electrochemical synthesis demonstrated excellent results for synthesis of ZnO nanorods on the surface of resonator electrodes.Efficiency of the piezoelectric chemisensors may be considerably enhanced by use of zinc oxide nanorods as sensing elements. ZnO nanorod arrays being good piezoelectric materials possess large surface area, which provides extra benefits for chemisorption and photodetection. Highly oriented nanorod arrays are typically prepared onto highly crystalline substrates, whereas the nanorods growth onto metal contacts meets significant technological difficulties. In this paper, we report on carbothermal, electrochemical, and hydrothermal techniques of ZnO nanorod arrays synthesis on metal contacts. The optical and structural properties of the obtained nanorods were studied using scanning electron microscopy, X-ray diffraction (XRD), Raman spectroscopy, and luminescence spectroscopy. A reliable technique was developed for obtaining ohmic contact with the grown nanorods. I–U curves of prepared contact were studied. Carbothermal synthesis made it possible to obtain the most crystallinely perfect, homogeneous, and dense arrays of nanorods and control the concentration of point defects by changing the synthesis parameters over a wide range. The electrochemical synthesis demonstrated excellent results for synthesis of ZnO nanorods on the surface of resonator electrodes.

The paper discusses the features of the effect of modification with lithium carbonate on the dielectric dispersion of lead ferroniobate ceramics. The modifier has been previously shown to change the ways of the recrystallization sintering and therefore reduce the sintering temperature of the ceramics, increase their average grain size, and improve their dielectric and piezoelectric properties. In this study, the emphasis is placed on the analysis of the diffusion effects of the ferroelectric phase transition upon such modification considered from the standpoint of the chemical specifics of the modifier and its location in the structure of the parent compound.The paper discusses the features of the effect of modification with lithium carbonate on the dielectric dispersion of lead ferroniobate ceramics. The modifier has been previously shown to change the ways of the recrystallization sintering and therefore reduce the sintering temperature of the ceramics, increase their average grain size, and improve their dielectric and piezoelectric properties. In this study, the emphasis is placed on the analysis of the diffusion effects of the ferroelectric phase transition upon such modification considered from the standpoint of the chemical specifics of the modifier and its location in the structure of the parent compound.

Some of the known binary ABO3perovskites with ferro- (FE) or antiferroelectric (AFE) at TC and different magnetic phase transitions (PT): ferro-and antiferromagnetic at TN and also some of their solid solutions are considered. Some correlations between their FE or AFE and/or magnetic PTs temperatures, on the one hand, and their interatomic bond A–O strains, on the other hand, have been constructed. It is shown that in the plotted diagrams these temperatures change with a change in δAO values as follows: classical FEs are followed by multiferroics, starting with BiFeO3 and ending with YVO3, followed by classical AFEs. At the same time, the temperatures TC and TN experience maxima at the corresponding points for BiFeO3, then quickly decrease, and the difference between them, TC-TN, basically also decreases, slightly increasing along the way to the point EuTiO3. which made it possible to systematize these TC and TN.Some of the known binary ABO3perovskites with ferro- (FE) or antiferroelectric (AFE) at TC and different magnetic phase transitions (PT): ferro-and antiferromagnetic at TN and also some of their solid solutions are considered. Some correlations between their FE or AFE and/or magnetic PTs temperatures, on the one hand, and their interatomic bond A–O strains, on the other hand, have been constructed. It is shown that in the plotted diagrams these temperatures change with a change in δAO values as follows: classical FEs are followed by multiferroics, starting with BiFeO3 and ending with YVO3, followed by classical AFEs. At the same time, the temperatures TC and TN experience maxima at the corresponding points for BiFeO3, then quickly decrease, and the difference between them, TC-TN, basically also decreases, slightly increasing along the way to the point EuTiO3. which made it possible to systematize these TC and TN.

Ceramics of quasi-binary concentration section (x = 0.50, 0.1 ≤y≤ 0.2, Δy = 0.025) of the ternary solid solution system (1−x−y)BiFeO3–xPbFe0.5Nb0.5O3–yPbTiO3 were prepared by the conventional solid-phase reaction method. By using X-ray diffraction technique, the phase diagram of the system was constructed, which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them. Grain morphology, dielectric and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient d33= 260 pC/N was obtained. Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior, a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350–500 K.Ceramics of quasi-binary concentration section (x = 0.50, 0.1 ≤y≤ 0.2, Δy = 0.025) of the ternary solid solution system (1−x−y)BiFeO3–xPbFe0.5Nb0.5O3–yPbTiO3 were prepared by the conventional solid-phase reaction method. By using X-ray diffraction technique, the phase diagram of the system was constructed, which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them. Grain morphology, dielectric and piezoelectric properties of the selected solid solutions were investigated. The highest piezoelectric coefficient d33= 260 pC/N was obtained. Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior, a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350–500 K.