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This study explores the structural, dielectric, impedance, and optical characteristics of the perovskite compound Sr(Mn${}_{0.45}$Fe${}_{0.05})$Nb${}_{0.5}$O₃. The compound was prepared by the solid-state mixed-oxide method. X-ray diffraction analysis confirmed a single-phase tetragonal crystal structure ($a=5.6425$ Å, $b=5.6425$ Å, $c=7.9468$ Å, space group I4/mcm). Morphological analysis revealed an almost uniform grain distribution with minimal spacing. The Maxwell–Wagner phenomenon was observed in the frequency-dependent dielectric properties by considering various polarization mechanisms. A dielectric anomaly indicating a ferroelectric to paraelectric phase transition was observed around 260^∘C during the temperature-dependent dielectric study. Impedance analysis demonstrated the NTCR behavior of the material. According to Jonscher’s power law, conduction is governed by nonoverlapping small polaron tunneling, explaining the relationship between conductivity with frequency. The activation energies for relaxation and conduction suggest electron hopping. Estimated band gap of 1.91eV is applicable for optoelectronic devices. The temperature-dependent resistance analysis indicates potential applications in N-type thermistors. The M–H hysteresis loop’s nonlinearity curve suggests weak ferromagnetism at low temperatures.

We present studies of the behavior of the permittivity of such liquid systems as pure distilled water, alcohol and 50%-aqueous solutions of alcohol as affected by the inerton field generated by a special signal generator contained within a wrist-watch or bracelet made by so-called Teslar^® technology. It has been found that the changes are in fact significant. The method employed has allowed us to fix the value of frequency of the field generated by the Teslar^® chip. The frequency has been determined to be approximately 8 Hz. The phenomenological consideration and submicroscopic foundations of a significant increase of the permittivity are studied, taking into account an additional interaction, namely, the mass interaction between polar water molecules, which is caused by the inerton field of the Teslar^® chip. This is one more proof of Krasnoholovets' concept regarding the existence of a substructure of the matter waves of moving/vibrating entities, i.e. the inerton field, which has been predicted in a series of his previous works.

Compositions with x=0.1, 0.2, 0.4, and 0.5 in the system (Pb_0.95Sr_0.05)·(Zr_0.53Ti_0.47)O₃+xwt%Cr₂O₃ (PSZTC) were synthesized using conventional ceramic method. Addition of Cr₂O₃ stabilized the tetragonal phase against the rhombohedral one. Scanning electron microscopy (SEM) showed a decrease of the mean grain size when increasing the doping level. The permittivity and electrical conductivities of the PSZTC compounds have been investigated and the activation energies were calculated.

Al³⁺-doped Ni–Zn ferrites with composition of Ni_0.5Zn_0.5(Fe_1-xAl_x)₂ O₄ (where x = 0, 0.012, 0.023, 0.035 and 0.045) were prepared by a method named "one-step synthesis." The magnetic and dielectric properties of the as-prepared Ni–Zn ferrites were investigated. X-ray diffraction data indicated that all the ferrite samples had a single-phase spinel structure. The addition of Al³⁺ resulted in a reduction of the grain size, lattice constant, density, shrinkage and saturation magnetization of the as-prepared samples. The Curie temperatures, however, raised first and reduced later with increasing contents of Al³⁺ in the samples, but still kept high values. Both the real and imaginary parts of permeability of ferrites decreased with increasing amount of Al³⁺ doped before they reached peak value. As the applied frequency increased to higher than about 10 MHz, the real part of permeability of non-doped ferrite had already become lower than those of ferrites doped with Al³⁺. Moreover, the doping of Al³⁺ made their utility of magnetic permeability move to much higher frequency. The observed decreases in dielectric constants and dielectric loss tangent could be attributed to the decreased electron conductivity by substituting Fe³⁺ with Al³⁺ in the samples. The as-prepared high-performance soft magnetic materials prepared using such a simple and low-cost method will be much promising in high-frequency applications and industrialization.

In the work nano silica has been irradiated by 2×10¹³ cm^-2s^-1 neutron flux at different times up to 20 h. The temperature and frequency dependencies of real and imaginary parts of dielectric constant of the nanomaterial exposed to neutron flux influence and initial state has been comparatively analyzed. From analysis results it has been revealed that the permittivity of nano SiO₂ increases in general tendency with influence of neutron flux. The mutual dependence of the real and imaginary parts of dielectric constant of nano SiO₂ particles has been reviewed. From the cases similar to Cole–Cole diagrams existing in the dependencies it has been revealed that the value of the relaxation period is compatible with polarization of the nano particles. It has been observed an increase in polarization with increase of influence period of neutron flux. Mechanisms of all effects observed in the experiments have been given.

An ultra-broad working temperature dielectric material, Bi₄Ti${}_x$O${}_{12}$($x$ = 2.96, 2.98, 3.0, 3.02 and 3.04), prepared by a conventional mixed oxide route was investigated which is supposed to replace lead-containing ceramics for its outstanding dielectric properties. Microstructure and dielectric properties of well-sintered samples (at 1040${}^{\circ }$C, 1060${}^{\circ }$C, 1080${}^{\circ }$C, 1100${}^{\circ }$C and 1120${}^{\circ }$C) were studied. X-ray diffraction analysis indicated that the new material was in a single Bi-layered perovskite phase. The dielectric constant and dielectric loss at different frequencies (10, 100 and 1000 kHz) were measured at 1100${}^{\circ }$C. With the increasing frequency, the dielectric constant decreased and the dielectric loss was almost unchanged. While at 100 kHz, there is the highest relative permittivity (${𝜀}_r$) of 2822.8 and the lowest dielectric loss of 0.0040 ($x$ = 2.98), the Curie temperature ($T_c$) is 668.9${}^{\circ }$C. At the frequency of 1 MHz, the highest relative permittivity (${𝜀}_r$) is 1115.8 when Ti content is 3.02, and the Curie temperature is 672.2${}^{\circ }$C. SEM can explain the results of the dielectric spectrum at different Ti content and sintering temperatures. $Z\ast$ plots show that Bi₄Ti₃O${}_{12}$ ceramics are a kind of dielectrics. Since it possesses large dielectric constant, low dielectric loss and stable temperature character, this material shows promising applications for the ultra-broad temperature range components, such as high-temperature multilayer ceramic capacitors and microwave ceramics.

Polyvinyl chloride (PVC) is widely used as insulator in electrical engineering especially as cable insulation sheaths. In order to improve the dielectric properties, polymers are mixed with ceramics. In this paper, PVC composites with different weight percentages 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared and investigated. Loss index (${𝜀}^{″}$) and dielectric constant (${𝜀}^{\prime }$) have been measured using an impedance analyzer RLC. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) have been used as characterization techniques. The incorporation of BaTiO₃ does not modify the crystallinity and the morphology of the PVC but reduces the space charges, therefore the dielectric losses. The frequency response analysis has been followed in the frequency ranges (20–140 Hz and 115–1 MHz). Relaxation frequencies have been evaluated in each frequency range. Experimental measurements have been validated using Cole–Cole’s model. Experimental results show well that BaTiO₃ as a filler improves the dielectric properties of PVC.

Magneto tunable left-handed material (LHM) which acts as a composite system has been theoretically demonstrated. The variation of the real and imaginary parts of the effective refractive index of the system is studied. The resonance that occurs in these studies are analyzed. The variation of impedance, reflectivity, absorptivity with frequency of the composite system was observed. The changes in resonance frequency with applied magnetic field are investigated. It is found that the resonance frequency increases with applied magnetic field.

In this work, the structure, dielectric and optical properties of PVDF/zirconia-based polymer nanocomposites were investigated. The morphology and structure of the nanocomposites were analyzed by XRD, SEM, FT-IR, UV and EDS analyses. It was determined that the forbidden gap for the PVDF/1%ZrO₂-based nanocomposite is 4.7eV, for PVDF/5%ZrO₂-4.5eV, and for PVDF/10%ZrO₂-4.2eV. It is shown that the dielectric permittivity of the nanocomposites increases sharply up to 3% of ZrO₂ nanoparticles in the polymer and then decreases slightly with an increase in the concentration of nanoparticles. An increase in the permittivity indicates an increase in polarization processes in nanocomposites at a 3% conentration of ZrO₂ nanoparticles in the PVDF matrix. It has been established that the dielectric loss tangent at low frequencies starts to decrease, and at high frequencies, it increases. The increase in the dielectric loss tangent at high frequencies is explained by an increase in relaxation processes and energy dissipation in these systems.

The solid solutions of Pb_1-xSm_x(Zr_0.50Ti_0.50)_1-x/4O₃ (PSZT), x = 0.00, 0.03, 0.06 and 0.09 were prepared by a mixed oxide method at high temperature (sintering temperature 1200°C). Preliminary X-ray structural analysis suggests the formation of single-phase compounds at room temperature in tetragonal crystal system. The microstructural SEM analysis shows that the grains of the materials are almost spherical and also uniformly distributed over the surface. Detailed studies of dielectric properties (ε, tanδ and σ) of the materials in a wide temperature range (30–500°C) at different frequencies (10³–10⁶ Hz) reveal that the compounds have transition temperatures well above the room temperature. The analysis of the diffusivity of the dielectric peaks in these compounds provides values between 1 and 2, where the higher values indicate great disorder in the system. The temperature dependence of ac conductivity and the value of activation energy in different regions suggest that the conduction process is of mixed type (i.e. singly ionized in ferroelectric region and doubly ionized in paraelectric phase).

SF₆–N₂ mixtures are becoming the best alternative for SF₆ in electrical systems. Plasmachemical modeling and the results of a positive surface streamer are reported in this paper. The model exhibits excellent streamer transition from the gas gap to the insulator surface. The surface charge accumulations on the dielectric insulators are compared and discussed. Results showed that the density of negative ions is much larger than that of electrons in the surface streamer channel. The dominant and less pronounced constitute the main negative ions in the electronegative surface streamer because of the strong electron attachments to SF₆ molecules.

In this paper, we continue the theoretical study of changes in optical characteristics of superlattices as a consequence of some specific behavior of excitons. Based on the particular dispersion law and the spectral distribution of excitons, we have formulated and calculated the refractive indices of these structures and defined how refractive indices change with external electromagnetic field. It was determined that among wide variety of parameters governing calculus, only two parameters have a significant effect on exciton energy spectra and calculated optical quantities: (a) the number of film layers which constitute superlattice; (b) ratio of the exciton energy transfer between the layers of one film and on the boundary between two different films.

Nanocrystalline 3C-SiC was irradiated by neutron flux ($2\times 10{}^{13}$ n$\cdot$cm${}^{-2}$s${}^{-1})$ up to 20h in the TRIGA Mark II type research reactor. The experiments have been conducted in the 0.1Hz–2.5MHz frequency and 100–400K temperature ranges. The frequency dependencies of real and imaginary parts of the permittivity of nanomaterial were analyzed comparatively before and after neutron irradiation. After neutron irradiation, there was increase in dopant element concentration in the nanocrystalline 3C-SiC particles. Concentration of new dopant elements in the 3C-SiC nanomaterial directly affects dielectric polarization and leads to increased permittivity. Simultaneously, after neutron irradiation, agglomeration and amorphous transformation influence on the polarization of nanocrystalline 3C-SiC. Moreover, 3C-SiC nanoparticle interface polarization gives rise to dispersion. It was found that ionic polarization was dominant in the nanocrystalline 3C-SiC particles.

Nanocrystalline 3C-SiC is irradiated by neutron flux ($2\times 10^{13}$n/cm²s) up to 20h in the TRIGA Mark II type research reactor. At the first stage, silicon carbide nanoparticles were analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM) devices before and after neutron irradiation. Amorphous transformation and agglomeration effects on the permittivity of nanocrystalline silicon carbide (3C-SiC) were comparisons investigated before and after neutron irradiation. Dielectric spectroscopies of nanocrystalline 3C-SiC have been conducted at the frequency ranges of 0.1Hz–2.5MHz and temperature ranges of 100–400K. Real and imaginary parts of the permittivity of the nanomaterial were analyzed for comparison before and after neutron irradiation. Neutron irradiation increased dopant elements concentration in the nanocrystalline 3C-SiC particles, and that directly affects dielectric polarization and increased permittivity. All the mechanisms of the observed effects are given in the work.

The film structures on the base of soft and crystalline ferroelectrics (poly(vinylidene fluoride - trifluoroethylene) copolymer and deuterated triglycine sulfate) were produced. The volume content of the DTGS microcrystal particles embedded in the polymer matrix of the composite films was up to 10%. It was found crystalline phase changes in the polymer matrix at the DTGS inclusions presence. The DTGS crystal particles increased dielectric permittivity and electrical conductivity of the composite films. The temperature dependences of the dielectric permittivity indicated increasing the phase transition temperature of polymer matrix at the DTGS inclusions growth.

Owing to the special planar structure and very high resistivity, $Z$-type hexaferrites possess the high initial permeability and cut-off frequency, indicating great application potential in high-frequency devices. Strontium Co₂Z hexaferrites (Sr₃Co₂Fe${}_{24}$O${}_{41}$) were successfully prepared by the sol–gel method and calcined at the different temperatures from $1175^{\circ }$C to $1250^{\circ }$C. The influence of the calcined temperatures on the microstructure, phase structures, magnetic properties and microwave absorption behavior of all samples was investigated in detail. All results indicated that strontium hexaferrites go through the $M$-, $Y$-, $Z$-, and $W$-phase transformation process from $1175^{\circ }$C to $1250^{\circ }$C, and S-1200 (calcined at $1200^{\circ }$C) is confirmed to be Co₂Z-type hexaferrites. S-1200 showed the highest imaginary permeability while the imaginary permittivity of all samples is close to zero, indicating the excellent microwave adsorption behavior of strontium Co₂Z hexaferrites. The reflection loss results indicate that S-1200 exhibits the best microwave absorption performance with the RL value of −32.4 dB for 4.0 mm thickness at 4.72 GHz, according to the impedance matching and quarter-wavelength theory.

Triangular voltage waveform was employed to distinguish the contributions of dielectric permittivity, electric conductivity and domain switching in current-electric field curves. At the same time, it is shown how those contributions can affect the shape of the electric displacement — electric field loops (D–E loops). The effects of frequency, temperature and microstructure (point defects, grain size and texture) on the ferroelectric properties of several ferroelectric compositions is reported, including: BaTiO₃; lead zirconate titanate (PZT); lead-free Na_0.5K_0.5NbO₃; perovskite-like layer structured A₂B₂O₇ with super high Curie point (T_c); Aurivillius phase ferroelectric Bi_3.15Nd_0.5Ti₃O₁₂; and multiferroic Bi_0.89La_0.05Tb_0.06FeO₃. This systematic study provides an instructive outline in the measurement of ferroelectric properties and the analysis and interpretation of experimental data.

In this paper, we present detailed investigations on the dielectric properties of Lithium (x = 0.10) and Potassium (y = 0.01, 0.02, 0.04, 0.05) mixed Sodium tri-titanate, Na_2-x-yLi_xK_yTi₃O₇ polycrystalline materials synthesized by solid-state reaction. The characteristics of the pelletized samples have been studied in the temperature range from 350 to 725 K and on the frequency in the range from 10 kHz to 1 MHz. The studies reveal that the chain structured Na_2-x-yLi_xK_yTi₃O₇ layered compound possesses electronic, ionic, dipolar, and space charge polarization mechanisms over the respective temperature regions in the entire temperature range of study.

In this paper, we investigate the possibility of using the heterogeneous materials, with cuboid metallic inclusions inside a dielectric substrate (host) to control the effective permittivity. We find that in the gigahertz range, such a material demonstrates a significantly larger permittivity compared to the pure dielectric substrate. Three principal orientations of microscale cuboid inclusions have been taken into account in this study. The highest permittivity is observed when the orientation provides the largest polarization (electric dipole moment). The detrimental side effect of the metallic inclusion, which leads to the decrease of the effective magnetic permeability, can be suppressed by the proper choice of shape and orientation of the inclusions. This choice can in fact reduce the induced current and hence maximize the permeability. The dissipative losses are shown to be negligible in the relevant range of frequencies and cuboid dimensions.

Ba(Mg${}_{1∕3}$Nb${}_{2∕3})$O₃ (BMN) doped and undoped Ba${}_{0.45}$Sr${}_{0.55}$TiO₃ (BST) thin films were deposited via radio frequency magnetron sputtering on Pt/TiO₂/SiO₂/Al₂O₃ substrates. The surface morphology and chemical state analyses of the films have shown that the BMN doped BST film has a smoother surface with reduced oxygen vacancy, resulting in an improved insulating properties of the BST film. Dielectric tunability, loss, and leakage current (LC) of the undoped and BMN doped BST thin films were studied. The BMN dopant has remarkably reduced the dielectric loss ($\sim$38%) with no significant effect on the tunability of the BST film, leading to an increase in figure of merit (FOM). This is attributed to the opposing behavior of large Mg${}^{2+}$ whose detrimental effect on tunability is partially compensated by small Nb${}^{5+}$ as the two substitute Ti${}^{4+}$ in the BST. The coupling between ${\text{Mg}}_{\mathrm{\text{Ti}}}^{″}$ and V${}_{\mathrm{\text{O}}}^{••}$ charged defects suppresses the dielectric loss in the film by cutting electrons from hopping between Ti ions. The LC of the films was investigated in the temperature range of 300–450K. A reduced LC measured for the BMN doped BST film was correlated to the formation of defect dipoles from ${\text{Mg}}_{\mathrm{\text{Ti}}}^{″}$, V${}_{\mathrm{\text{O}}}^{••}$ and Nb${}_{\mathrm{\text{Ti}}}^{•}$ charged defects. The carrier transport properties of the films were analyzed in light of Schottky thermionic emission (SE) and Poole–Frenkel (PF) emission mechanisms. The result indicated that while the carrier transport mechanism in the undoped film is interface limited (SE), the conduction in the BMN doped film was dominated by bulk processes (PF). The change of the conduction mechanism from SE to PF as a result of BMN doping is attributed to the presence of uncoupled Nb${}_{\mathrm{\text{Ti}}}^{•}$ sitting as a positive trap center at the shallow donor level of the BST.