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The complex dielectric permittivity of tungsten oxide at all stages of its colouration in a hydrogen-rich atmosphere was retrieved from measured VIS-NIR ellipsometric spectra of WO 3 /Pd bilayer. The retrieval was done by fitting the spectra with the Cody-Lorentz dispersion model, and, for optical absorption features, two Gaussian functions were added. The band gap edge, the Gaussian center energies, amplitudes, spectral widths and integrals were traced as the redox reaction progressed. Analysis of obtained data provides insight into mechanism of surface and bulk oxygen vacancies formation. We discuss these peculiarities in detail and show how they do affect the optical constants of WO 3 – x and potential sensors' response rates. • Ellipsometry for dielectric permittivity of WO 3 -x subjected to stepwise colouration in a hydrogen-rich atmosphere. • Absorption feature associated with WO 3 reduction was described by two competing processes fitted by Gaussians. • To elucidate the colouration mechanism, the Gaussians parameters were traced, illustrating oxygen vacancies formation. [ABSTRACT FROM AUTHOR]

A novel quaternary medium-entropy rock-salt oxide (Mg 0.25 Co 0.25 Ni 0.25 Zn 0.25)O (MERO) was predicted using first-principles calculation and prepared through solid-state reaction. The first-principles study demonstrated that the mixing enthalpy and entropy values of the MERO are 2.377 kJ/mol and 0.693–1.040 R, respectively. The single-phase MERO can be obtained from 1000 °C to 1200 °C, demonstrating good thermal stability, whereas a completely disordered occupancy of different metal cations can be confirmed by Raman spectroscopy. The Transition Electron Microscope (TEM) analysis reveals that the MERO exhibits an FCC structure with a lattice parameter of 4.384 Å. The dielectric permittivity ε r of MERO prepared at 1200 °C shows relatively high values of 6.4 × 103 and 18.40 corresponding to frequencies of 100 Hz and 1 MHz at room temperature, exhibiting a potential for application in electrode materials and capacitors. [ABSTRACT FROM AUTHOR]

This study employs a method, integrating a double calcination process with a solid-state reaction, to diminish the loss tangent of Gd 2/3 Cu 3 Ti 4 O 12 and Sm 2/3 Cu 3 Ti 4 O 12 ceramics. Fine-grained microstructures can be detected in sintered Gd 2/3 Cu 3 Ti 4 O 12 and Sm 2/3 Cu 3 Ti 4 O 12 ceramics. The dielectric constants of Gd 2/3 Cu 3 Ti 4 O 12 and Sm 2/3 Cu 3 Ti 4 O 12 ceramics vary within the range of 4.14 × 103 to 6.82 × 103 at room temperature and 1 kHz. Additionally, Sm 2/3 Cu 3 Ti 4 O 12 displays an impressively low loss tangent, ranging from 0.017 to 0.019. X-ray photoelectron spectroscopy can detect the presence of both Cu+/Cu2+ and Ti3+/Ti4+ states, which may be influenced by oxygen vacancies within the lattice. Theoretical calculations using density functional theory have demonstrated that both Sm and Gd ions can increase oxygen vacancy concentrations, leading to a reduction in the loss tangent of these ceramics. Moreover, electron density analysis revealed that the presence of oxygen vacancies in this structure is responsible for the Cu+ and Ti3+ states observed in our XPS experiments. Lastly, the observed dielectric response in both Gd 2/3 Cu 3 Ti 4 O 12 and Sm 2/3 Cu 3 Ti 4 O 12 ceramics is probably attributed to a heterogeneous microstructure and the cumulative effects arising from both the grain and grain boundaries. [ABSTRACT FROM AUTHOR]

In the present study, NdFeO3 (NFO), Nd(0.9)Ba(0.1)FeO3 (NBFO), NdFe(0.9)Mn(0.1)O3 (NFMO) and Nd(0.9)Ba(0.1)Fe(0.9)Mn(0.1)O3 (NBFMO) were successfully synthesized using citrate sol–gel chemical route. X-ray diffraction (XRD) patterns confirm the formation of orthorhombic perovskite structure with space group Pbnm and are further complemented by the Rietveld refinement. Scherrer's formula as well as Williamson–Hall (W–H) plot was used to calculate average crystallite size of the prepared samples. Further, morphological investigations were carried out using SEM imaging and EDX spectroscopy. Dielectric properties including frequency dependence of dielectric permittivity (ε), tangent loss (tan δ) and electrical conductivity (σ) of all the samples were analysed at different temperature ranges from 300 to 623 K over a frequency range from 100 Hz to 1 MHz. It was found that the ε decreases with the increase in frequency. Optical properties were investigated using the UV–visible spectroscopy and the Tauc's plot was employed on the absorbance spectra for calculating the energy band gap. It was found that the band gap decreases as the dopants are inserted in the lattice of NFO. Magneto-dielectric properties were analysed by using varying magnetic field from 0 to 2 T. These samples could serve as the properties of materials with potential applications in logic gate, data storage, switches and sensors. [ABSTRACT FROM AUTHOR]

Magnesium-doped nickel ferrite nanoparticles with the chemical composition (Ni1−xMgxFe2O4, x = 0.00, 0.20, and 0.40) have been prepared by a modified sol–gel citrate method. Structural analysis was carried out through x-ray diffractograms (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The spherical-shaped morphology of the prepared nanoparticles has been confirmed by field-emission scanning electron microscopy (FESEM). The energy dispersive x-ray (EDX) analysis confirmed the presence of elements (Ni, Mg, Fe, and O) in the prepared compositions. The distribution of cations over tetrahedral and octahedral sites has been confirmed by Rietveld refinement using FullProf software. The phenomena of Maxwell–Wagner polarization is exhibited in the dielectric measurements. Cole–Cole plots showed that the net grain (Rg) and grain boundary resistance (Rgb) values are decreasing for the maximum concentration of Mg2+ ions in the nickel ferrites. Almost 96% deductions in the tangent loss values have been observed at high temperatures with the increasing concentration of Mg2+ ions in the nickel ferrites. Fitting of AC conductivity was carried out using the Jonscher Power Law function. The net magnetization saturation values also decreased from 27.7 emu/g to 16.7 emu/g upon the doping of Mg2+ ions in the pure nickel ferrites. These properties are all desired for materials working under high-frequency applications. [ABSTRACT FROM AUTHOR]

The continuous upgrading of electronic technology has facilitated the integration and miniaturization of electronic and electrical equipment, as well as putting great pressure on the multifunctional demand for internal materials. Developing insulating materials with both low permittivity and high thermal conductivity has become imperative. This perspective focuses on polyimide (PI), which is the top material of the polymer material pyramid, discusses the characteristic parameters that affect its dielectric property and thermal conductivity. A series of basic schemes to regulate the dielectric/thermal properties of PI are summarized, revealing the bottlenecks and drawbacks of the current research. Future development trends of PIs featured low permittivity-high thermal conductivity are anticipated, and novel ideas are proposed for the development of new generation of multifunctional PIs. [ABSTRACT FROM AUTHOR]

Forest ecosystems face increasing drought exposure due to climate change, necessitating accurate measurements of vegetation water content to assess drought stress and tree mortality risks. Although Frequency Domain Reflectometry offers a viable method for monitoring stem water content by measuring dielectric permittivity, challenges arise from uncertainties in sensor calibration linked to wood properties and species variability, impeding its wider usage. We sampled tropical forest trees and palms in eastern Amazônia to evaluate how sensor output differences are controlled by wood density, temperature and taxonomic identity. Three individuals per species were felled and cut into segments within a diverse dataset comprising five dicotyledonous tree and three monocotyledonous palm species on a wide range of wood densities. Water content was estimated gravimetrically for each segment using a temporally explicit wet-up/dry-down approach and the relationship with the dielectric permittivity was examined. Woody tissue density had no significant impact on the calibration, but species identity and temperature significantly affected sensor readings. The temperature artefact was quantitatively important at large temperature differences, which may have led to significant bias of daily and seasonal water content dynamics in previous studies. We established the first tropical tree and palm calibration equation which performed well for estimating water content. Notably, we demonstrated that the sensitivity remained consistent across species, enabling the creation of a simplified one-slope calibration for accurate, species-independent measurements of relative water content. Our one-slope calibration serves as a general, species-independent standard calibration for assessing relative water content in woody tissue, offering a valuable tool for quantifying drought responses and stress in trees and forest ecosystems. [ABSTRACT FROM AUTHOR]

The mechanically cleaved flake of ternary metal chalcogenide PbSnSe 2 was transferred onto the interdigitated electrodes to form electrical contacts. The temperature dependent (180 K–250 K) electrical properties were then analyzed employing complex impedance spectroscopy from 2 kHz to 2 MHz. A detailed analysis of Nyquist plots proposed the space charge dependent behavior and negative temperature coefficient of PbSnSe 2 flake. The AC conductivity followed Jonscher's power law with s -parameter value being less than unity. The values of s -parameter increased with rise in temperature suggesting the presence of non-overlapping small polaron tunneling (NSPT) in the PbSnSe 2 flake. From this NSPT model, tunneling distance, hopping energy, and density of states (DOS) were estimated at temperatures from 180 K–250 K. The dielectric permittivity showed dispersion at lower frequencies and the tangent loss was also found to be directly related to temperature. A single semicircular arc in complex modulus analysis showed the dominance of bulk effect in the material. [ABSTRACT FROM AUTHOR]

Two ranges of dielectric permittivity (k) increase in polymer composites upon the modification of BaTiO3 filler with multiwalled carbon nanotubes (MWCNTs) are shown for the first time. The first increase in permittivity is observed at low MWCNT content in the composite (approximately 0.07 vol.%) without a considerable increase in dielectric loss tangent and electrical conductivity. This effect is determined by the intensification of filler–polymer interactions caused by the nanotubes, which introduce Brønsted acidic centers on the modified filler surface and thus promote interactions with the cyanoethyl ester of polyvinyl alcohol (CEPVA) polymer binder. Consequently, the structure of the composites becomes more uniform: the permittivity increase is accompanied by a decrease in the lacunarity (nonuniformity) of the structure and an increase in scale invariance, which characterizes the self-similarity of the composite structure. The permittivity of the composites in the first range follows a modified Lichtenecker equation, including the content of Brønsted acidic centers as a parameter. The second permittivity growth range features a drastic increase in the dielectric loss tangent and conductivity corresponding to the percolation effect with the threshold at 0.3 vol.% of MWCNTs. [ABSTRACT FROM AUTHOR]

The quality of asphalt pavement (HMA) is often assessed by its dielectric permittivity, e.g., using ground-penetrating radar technology. The mostly employed relationships were developed for dry HMA pavement as follows: Complex Refractive Index Model (CRIM), Bottcher, Rayleigh, and Al-Qadi–Lahouar–Leng models (so-called ALL model), while the relationships for the estimation of wet HMA properties are empiric and not consistent with those for dry HMA mixtures. The article presents the results of the development and analysis of novel relationships between the values of dielectric permittivity and the mechanical characteristics of wet asphalt. It is shown that the new relationships are the general consistent cases of the expressions previously developed for dry HMA. The new expressions for the Rayleigh and ALL models are shown providing close estimates for the value of moisture content in the range of porosity and degree of water saturation: 0–0.12 and 0–1, respectively, and in the wide range of aggregate specific gravity (2.5–2.9), the binder content (0.04–0.08), the dielectric permittivity of aggregate (6–11), and the maximum specific gravity (2.5–2.9). Since the ALL model is an implicit function, in which the dielectric permittivity variable cannot be extracted, the direct problem (to calculate the dielectric constant value from density/specific gravity and porosity value) can be solved numerically while the inverse problem can be solved algebraically. The newly developed expression for the Rayleigh model (for wet asphalt) can be used for the estimation of dielectric permittivity based on expected values of porosity and density, and vice versa, and hence it is simpler for using. [ABSTRACT FROM AUTHOR]

Complex dielectric measurements were performed in 1-nitropropane (NTP) and DMSO mixtures at various concentrations in the frequency range of 10 MHz to 50 GHz using time domain reflectometry technique. The excess inverse relaxation time values were found to be negative, indicating that the dipoles rotated more slowly. Alenka Luzar's hydrogen-bonded theory is used to calculate theoretical estimates of the static dielectric constant. The variations in dielectric parameters such as dielectric constant, relaxation time, Kirkwood correlation factor and excess properties observed in the study confirm the existence of intermolecular interactions within the NTP-DMSO mixtures. [ABSTRACT FROM AUTHOR]

Semiconducting nanofluids (SNFs), based on poly(ethylene glycol) (PEG200) fluid with the dispersion of 0.01 wt% mono (ZnO, TiO2, and OMMT) and 0.01+ 0.01 wt% hybrid (ZnO+OMMT, ZnO+TiO2, and TiO2+OMMT) nanomaterials, are prepared through mixing and then ultrasonic cavitation homogenised process. Ultraviolet-visible (UV-Vis) absorbance spectra of these SNFs are recorded in the 200–800 nm range and analysed for their photosensitivity and UV shielding performance and also for nanomaterials tunable dual band gaps ranging from 3 to 5 eV. The rheological investigations on these samples, at 303.15 K, validate Newtonian nanofluids of high dynamic viscosity (η ≈ 32 mP.s). Static dielectric permittivity (εs ≈ 22) and electrical conductivity (σdc ≈ 8 μS/cm) of these SNFs at 303.15 K are found marginally affected by the dispersed mono and hybrid nanomaterials. Comparative experimental results presented here in on a variety of SNFs provide a guideline for their uses in developing soft condensed matter based innovative devices. [ABSTRACT FROM AUTHOR]

The most recent research and developments are driven by colossal permittivity (CP) materials due to their potential use in modern microelectronics and high-energy density storage applications. Even though, to date, many CP materials have been discovered, the task of developing them with the required high performance remains highly challenging. We present a tangible example, polycrystalline ZnO ceramic, that presents a highly frequency-stable CP (> 104) as well as a low dielectric loss (~ 0.3) over a broad temperature range from 278 to 433 K. Multifunctional polycrystalline ZnO nanoceramics are prepared through one-pot hydrothermal route and sintered at 300 °C and 600 °C. The highly magnified scanning electron microscopic images reveal excellent grain growth at high temperature. Temperature-dependent impedance spectroscopy is employed for pellet sintered at (600 °C) to explore different conduction mechanisms at various temperature ranges. The distribution of relaxation times (DRT) method is used to design the best equivalent circuit model for fitting impedance data. The non-Debye behavior of real permittivity (ɛ′) is well explained by fitting with Cole–Cole formalism. The change in the conduction mechanism is estimated around 343 K, and an adiabatic polaronic model is used to estimate activation energies of cations through different electroactive regions. The correlate barrier hopping (CBH) model is applied to measure electrical trapping parameters (like binding energy, hopping distance, barrier height, etc.) at various temperatures. Our finding presents a systematic approach toward frequency-independent ZnO ceramics with a stable colossal permittivity which can potentially be applied to develop energy storage devices. [ABSTRACT FROM AUTHOR]

A thorough understanding of the interplay between polarization mechanisms is pivotal for the interpretation of electrical measurements, since sub-megahertz electrical measurements in sedimentary rocks are dominated by interfacial polarization mechanisms. Nonetheless, rock-physics models oversimplify pore-network geometry and the interaction of electric double layers relating to adjacent grains. Numerical algorithms present the best possible framework in which to characterize the electrical response of sedimentary rocks, avoiding the constraints intrinsic to rock-physics models. Recently, an algorithm was introduced that can simulate the interactions of electric fields with the ions in solution. The sub-kilohertz permittivity enhancement in sedimentary rocks is dominated by Stern-layer polarization, but a model for the polarization mechanism associated with the Stern layer has not been developed. Hence, the aim of this paper is to develop and test a numerical simulation framework to quantify the influence of Stern- and diffuse-layer polarization, temperature, ion concentration, and pore-network geometry on multi-frequency complex electrical measurements. The algorithm numerically solves the Poisson–Nernst–Planck equations in the time domain and a mineral-dependent electrochemical adsorption/desorption equilibrium model to determine surface charge distribution. Then, the numerical simulator is utilized to perform a sensitivity analysis to quantify the influence of electrolyte and interfacial properties on the permittivity of pore-scale samples at different frequencies. [ABSTRACT FROM AUTHOR]

In this paper, the electrical conductivity characteristic of polyaniline (PANI) coated CuO nanocomposites of different wt% of CuO nanoparticles can be studied. The synthesis of PANI/CuO nanocomposites was done by in-situ chemical polymerization reaction. Spectroscopic characterizations were done using FTIR, SEM, TGA, XRD, and UV-Vis techniques. The presence of functional groups, surface morphology, and semi-crystalline nature of the sample can be confirmed by FTIR, SEM, and XRD studies. High thermal stability of the sample was confirmed by TGA studies. The frequency-dependent AC conductivity and dielectric attributes of nanocomposites studied at normal room temperature showed tunability with varying wt% of CuO indicating PANI/CuO (5%) exhibits high AC conductivity and dielectric constant values than (10% &15%). It can be observed that the presence of CuO in PANI affects EMI shielding. The synthesized nanocomposites showed excellent EMI Shielding effectiveness of -18.2 dB to -23.1 dB. The results indicate PANI/CuO nanocomposites utilized as potential shielding materials in X-Band. Also, the PANI/CuO/GC electrode expresses good sensing performance for Dopamine. Further PANI/CuO/GCE shows excellent long linear range, sensitivity, and LOD are 10 to 180 µmol/L, 0.0153 and 3.666 and R² is 0.9951. Also, this sensor shows repeatability and stability without leaching property. [ABSTRACT FROM AUTHOR]

This study involves the synthesis of CuO–ZnO nanocomposites with varying Sb doping levels (0%, 2.5%, and 5%) through a facile sol-gel process. Structural analysis via X-ray diffraction confirmed the presence of ZnO's hexagonal wurtzite phase and CuO's monoclinic phase in all samples, indicating reduced crystallinity due to doping. The average crystallite size was determined using Scherrer's formula, revealing a decrease in size with doping (33 nm, 31 nm, and 30 nm for 0%, 2.5%, and 5% Sb, respectively). Morphology and chemical composition were assessed using field emission scanning electron microscopy, and energy dispersive X-ray analysis. The optical bandgap of the Sb-doped CuO–ZnO nanocomposites was determined using a Tauc plot, resulting in values of 2.48 eV, 2.39 eV, and 2.32 eV for dopant concentrations of 0%, 2.5%, and 5%, respectively. Dielectric permittivity and tangent loss were studied across the frequency range of 100 Hz to 1 MHz at different temperatures ranging from 303 K to 723 K measured between 100 Hz and 1 MHz frequency, revealing Maxwell-Wagner-type interfacial polarization. The dielectric permittivity data reveal anomalous behavior near 673 K, shifting with doping, and is explained by thermal ionization and relaxation mechanisms. The ac conductivity, which varies with frequency, demonstrates low-frequency dispersion and is effectively described by Jonscher's power law aligned with the dielectric analysis. Magneto-dielectric measurements showed a positive effect for permittivity and a negative effect for tangent loss, which may be caused by the changes in dipole alignment. The magneto-dielectric effect was further explored by analyzing the impact of magnetic fields (0–1.5 T) on impedance spectroscopy. Nyquist plots obtained at various magnetic fields were fitted using parallel combinations of resistance-capacitor circuits. These plots were then employed to estimate the contributions of both grains and grain boundaries. Overall, the findings from this study provide a foundation for the development of multifunctional materials with tailored properties for a wide range of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Structural, mechanical, and electrophysical properties of rhombohedral hafnium oxide (r‐HfO2) with space group R3, as well as properties of HfO2, ZrO2, and Hf0.5Zr0.5O2 with space group Pca21 are studied using quantum chemical calculations. The characteristic diffraction peak of 2θ r‐HfO2 is close to the characteristic diffraction peaks of tetragonal (t‐HfO2) and orthorhombic (f‐HfO2) hafnium oxide. The value of bulk modulus is 231 GPa, which is larger than one of the orthorhombic structures. The values of high intensity peaks of Raman spectrum are 670 and 540 cm−1. The bandgap width is 5.8 eV and the average value of dielectric constant is 35.34, which is higher than one of orthorhombic hafnium oxide. [ABSTRACT FROM AUTHOR]

This study investigates the dielectric properties of conductive biocomposites (CBs), which are integral to the development of advanced materials for flexible electronics and medical devices. A novel method employing Microwave Reflectometry (MR) is introduced, utilizing a miniaturized Vector Network Analyzer (m-VNA) and a dedicated sensing element (SE), to extract the dielectric properties of CBs. The method is grounded in a minimization principle, aligning the measured S 11 reflection scattering parameter with its electromagnetic (EM) simulation, facilitating a refined process for determining the dielectric properties. The experimental setup was meticulously engineered, optimized, and validated using reference dielectric samples (RDSs) with known dielectric properties. The method was then applied to three innovative CBs, resulting in an accurate extrapolation of their dielectric properties. The findings highlight the method's versatility, cost-efficiency, and applicability to ultra-thin and flexible biopolymer films, offering significant potential for advancements in flexible electronics and bio-sensing applications. [ABSTRACT FROM AUTHOR]

Lead-free K0.5Bi0.5TiO3 (KBT) ceramics with high density (~5.36 g/cm3, 90% of X-ray density) and compositional purity (up to 90%) were synthesized using a solid-state reaction method. Strongly condensed KBT ceramics revealed homogenous local microstructures. TG/DSC (Thermogravimetry-differential scanning calorimetry) techniques characterized the thermal and structural stability of KBT. High mass stability (>0.4%) has proven no KBT thermal decomposition or other phase precipitation up to 1000 °C except for the co-existing K2Ti6O13 impurity. A strong influence of crystallites size and sintering conditions on improved dielectric and non-linear optical properties was reported. A significant increase (more than twice) in dielectric permittivity (εR), substantial for potential applications, was found in the KBT-24h specimen with extensive milling time. Moreover, it was observed that the second harmonic generation (λSHG = 532 nm) was activated at remarkably low fundamental beam intensity. Finally, spectroscopic experiments (Fourier transform Raman and far-infrared spectroscopy (FT-IR)) were supported by DFT (Density functional theory) calculations with a 2 × 2 × 2 supercell (P42mc symmetry and C4v point group). Moreover, the energy band gap was calculated (Eg = 2.46 eV), and a strong hybridization of the O-2p and Ti-3d orbitals at Eg explained the nature of band-gap transition (Γ → Γ). [ABSTRACT FROM AUTHOR]

BACKGROUND: Food adulteration has long been considered a major problem. It compromises the quality, safety, and nutritional value of food, posing significant risks to public health. Novel techniques are required to control it. RESULTS: A graphene‐based T‐shaped monopole antenna sensor was tested for its ability to detect adulteration in liquid foods. Mustard oil was the pure reference sample used for product quality analysis. Olive oil and rice bran oil were adulterants added to the pure sample. It was found that the sensor could be immersed easily in the liquid sample and provided precise results. CONCLUSION: The graphene‐based T‐shaped monopole antenna sensor can be used for the quality assessment of liquid food products and is suitable for real‐time monitoring. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Modern technology has been facilitated by the combination of liquid crystals (LCs) and nanomaterials (NMs) which led to tunable and responsive LC-based devices. This is very common among all LCs-based devices that they are driven by an electric field which causes the reorientation of LCs molecules. The ions that are normally present in the LCs material can affect the reorientation process of LCs molecules due to the screening effect. The NMs play an important role in controlling the number of ions either by ion-capturing or ion-releasing processes. Therefore, it is necessary to understand about the effect of different NMs on the ions in LCs. To achieve this goal, we have studied the effects of vanadium-doped titanium oxide (VTO) nanoparticles (NPs) on the dielectric properties of nematic LCs (NLCs). Various dielectric parameters such as dielectric permittivity, dielectric loss, dielectric loss factor, and dielectric anisotropy have been studied at different temperatures for different concentrations (0, 0.05, 0.10, 0.25, and 1.00 wt.%) of VTO NPs in host 5CB LC material. We have observed a significant change in the dielectric parameters of the 5CB LC material after the dispersion of the VTO NPs in the low-frequency region. These changes may be attributed to the presence of ionic impurities in the pure and dispersed 5CB materials. To confirm the role of ionic impurities on the dielectric properties, we have calculated the ion concentration and diffusion constant for various concentrations of NPs by fitting the dielectric loss data according to Uemera formalism. We have observed an increase in the ion concentration with the dispersion of NPs up to 0.25 wt.%. We have also noticed an increase in the threshold voltage and dielectric anisotropy with the dispersion of NPs. The increase in the dielectric parameters of the pure 5CB LC material after dispersion of the VTO NPs is attributed to the ion-releasing nature of the VTO NPs. These studies may be useful for various applications of LC materials in which the presence of ions effectively enhances the properties of LC-based devices. [ABSTRACT FROM AUTHOR]

Deriving analytical expressions of dielectric permittivities is required for numerical and physical modeling of optical systems and the soar of non‐Hermitian photonics motivates their prolongation in the complex plane. Analytical models are based on the association of microscopic models to describe macroscopic effects. However, the question is to know whether the resulting Debye–Drude–Lorentz models are not too restrictive. Here, it is shown that the permittivity must be treated as a meromorphic transfer function that complies with the requirements of complex analysis. This function can be naturally expanded on a set of complex singularities. This singularity expansion of the dielectric permittivity allows to derive a generalized expression of the Debye–Drude–Lorentz model that complies with the requirements of complex analysis and the constraints of physical systems. It is shown that the complex singularities and other parameters of this generalized expression can be retrieved from experimental data acquired along the real frequency axis. The accuracy of this expression is assessed for a wide range of materials including metals, 2D materials and dielectrics, and it is shown how the distribution of the retrieved poles helps in characterizing the materials. [ABSTRACT FROM AUTHOR]

Biological-formed fossilized diatom sediments have unique physical, electrical, and mechanical properties due to the shape, internal open porosity, and brittleness of the individual particles. The presence of diatoms strongly influences the overall behavior of soils. However, engineers and researchers find this influence challenging to quantify because measuring fossilized diatom content is elusive. This paper uses simple physical, electromagnetic, and mechanical engineering measurements to characterize the response of the artificial soils prepared with known amounts of fossilized diatoms under different pore-chemistry fluid and mechanical environments. Soils with high fossilized diatom content tend to retain high quantities of water even under high NaCl-concentration pore fluid. This response results from the internal porosity and is not a function of electrical forces on the particle surface. Furthermore, internal porosity governs electrical and mechanical properties under different pore fluid environments. Despite having elevated Liquid Limits, soils with high fossilized diatoms content do not deform while drying and changing pore fluid salt concentration. However, fossilized diatoms are brittle and offer high compressibility and low particle crushing stress (around 2–4 MPa). Our results show that simple physical and index tests can help assess the effect of fossilized diatoms' in soils, and provide a framework to predict the engineering properties of natural soils containing a wide range of fossilized diatoms even when diatom content cannot be precisely measured. [ABSTRACT FROM AUTHOR]

In this paper, we address the approximation of the coupling problem for the wave equation and Maxwell's equations of electromagnetism in the time domain in terms of electric field by means of a nodal linear finite element discretization in space, combined with a classical explicit finite difference scheme for time discretization. Our study applies to a particular case where the dielectric permittivity has a constant value outside a subdomain, whose closure does not intersect the boundary of the domain where the problem is defined. Inside this subdomain, Maxwell's equations hold. Outside this subdomain, the wave equation holds, which may correspond to Maxwell's equations with a constant permittivity under certain conditions. We consider as a model the case of first-order absorbing boundary conditions. First-order error estimates are proven in the sense of two norms involving first-order time and space derivatives under reasonable assumptions, among which lies a CFL condition for hyperbolic equations. The theoretical estimates are validated by numerical computations, which also show that the scheme is globally of the second order in the maximum norm in time and in the least-squares norm in space. [ABSTRACT FROM AUTHOR]

In this study, polyethylene oxide (PEO)/polyvinyl alcohol (PVA) nanocomposite films incorporated with different concentrations of graphene oxide nanoparticles (GO NPs) were fabricated and characterized. The nanocomposites were characterized by XRD, FT-IR, optical spectroscopy, tensile testing, and electrical conductivity. The X-ray results suggest that adding of GO to PEO/PVA improves their compatibility and causes a decrease in the degree of crystallinity. The FT-IR spectra suggest the creation of stronger hydrogen bonds between the PEO/PVA polymeric chains and the GO as a filler. The absorbance spectra show increased UV-vis absorbance after adding GO nanopowders. The Tauc equation was used to calculate the optical band gap (Eg) which increased after adding GO nanopowders. The mechanical and electrical properties of the samples are also studied. The results reveal that incorporating GO led to an overall reinforcing effect on the mechanical and dielectric properties. Moreover, the frequency of the electric field, the concentrations of the GO NPs, and interfacial interactions between GO and the polymer matrix were identified as important factors that can influence the dielectric property of the nanocomposite. In addition, the relationship between Z' and Z" of the PEO/PVA-GO films provided important insights into the electrical behavior. The best PEO/PVA-GO nanocomposite sample shows potential for various applications, including electronics, battery energy storage and engineering field. [ABSTRACT FROM AUTHOR]

Aggregates largely influence a road's dielectric properties, which is an important physical parameter when using non-destructive methods such as ground penetrating radar to evaluate a road's geometry. Due to the irregular shapes, the direct measurement of an aggregate piece by piece in the microwave domain is not easy. To address this problem, an epoxy-based composite is used to estimate the dielectric constant of the aggregates by resonant test and mixing law calculation. As a water-free binder, the epoxy composite eliminates the water effect on the dielectric properties. Meanwhile, the distribution of each component can be studied by X-ray computed tomography, which allows knowing the composite's morphology. Moreover, the composite has a smooth surface that avoids the texture effects on the dielectric measurement. In addition, the impedance analysis of individual aggregates at low frequencies was used to evaluate the results obtained with composites and mixing laws. [ABSTRACT FROM AUTHOR]

In this work, a small planar microwave sensor based on a band-stop filter is proposed for measuring the relative permittivity of the materials. The operation frequency of the presented sensor is 2.24 GHz. It is composed of a microstrip line and an M-shaped slot as the host and sensing area respectively. This structure has been fabricated with printed circuit board (PCB) technology on the RO4003c. The sensing performance has been verified through the fabrication and measurement of a prototype to characterize the solid and the liquid samples. The correlation between the resonance frequency and relative permittivity is almost linear. The resonant frequency variation of the proposed sensor (2.24 GHz to 1.97 GHz) is proportional to dielectric constant of samples under test which is in a wide from 2.43 to 80 This sensor illustrates superior performances in comparison with similar structures in the fields of broad-range permittivity for Material under test (MUT) and the size of the transducer. The experimental results for solid-liquid materials indicate that the normalized sensitivity is 1.43% - 0.95% which is better than most similar structures. The size of the proto-type sensor (7mm $\times 14$ mm $\times 0.508$ mm) is smaller than those reported in the literature.

Blackbody radiation is incoherent and omnidirectional, whereas various novel applications in renewable energy require a degree of directional control of a thermally emitted beam. So far, such directional control has required nano-structuring the surface of a thermally emitting material, typically by forming diffraction gratings. This, however, necessitates lithography and usually results in polarization-dependent properties. Here, we derive analytical conditions for highly directional thermal emission using a planar 3-layer structure analogous to a Salisbury screen. We present design rules for maximizing the directionality of such structures. Notably, these design rules pertain to both linear polarizations, thus generalizing the principles of a grating for unpolarized light. We show that the key requirement to achieve such performance is ultra-high quality factor resonances in materials supporting phonon polaritonic modes, as those found in low-dimensional materials. We propose a realistic device based on hexagonal Boron Nitride and predict performances comparable to lithography-based nano-structures.

This work presents the dielectric and ultrasonic properties of polydimethylsiloxane (PDMS) nanocomposites filled with titanium dioxide nanoparticles. The dielectric study was performed over a very broad range of frequencies (20 Hz–3 THz). The dielectric permittivity was almost frequency-independent in all the composites at room temperature over the whole range of measurement frequencies, and the dielectric losses were very low under these conditions (less than 2). The dielectric permittivity strongly increases with the nanoparticle concentration according to the Maxwell–Garnet model. Therefore, the investigated composites are suitable for various flexible electronic applications, particularly in the microwave and terahertz frequency ranges. Dielectric dispersion and increased attenuation of ultrasonic waves were observed at lower temperatures (below 280 K) due to the relaxation of polymer molecules at the PDMS/TiO2 interface and in the polymer matrix. The relaxation time followed the Vogel–Vulcher law, while the freezing temperature increased with the titanium dioxide concentration due to interactions between the polymer molecules and nanoparticles. The significant hysteresis in the ultrasonic properties indicated that titanium dioxide acts as a crystallization center. This is confirmed by the correlation between the hysteresis in the ultrasonic properties and the structure of the composites. The small difference in the activation energy values obtained from the ultrasonic and dielectric investigations is related to the fact that the dielectric dispersion is slightly broader than the Debye-type dielectric dispersion. [ABSTRACT FROM AUTHOR]

State‐of‐the art Electrochemical Double‐Layer Capacitors (EDLCs) usually extend their operating electrochemical stability window (ESW) by means of organic electrolytes, or highly concentrated aqueous (water‐in‐salt) electrolytes hindering parasitic water splitting reactions. Unfortunately, organic solvents and high concentrations of ions penalize the dielectric constant of the electrolyte, hence the capacitive performance. We suggest here a new concept of cost‐effective and sustainable aqueous electrolytes based on concentrated amino acid water solutions with a dielectric permittivity much higher than pure water, unlocking the capacitive performance of aqueous EDLC references. Amino acids are natural zwitterionic molecules with a large separation between the positive and negative moiety, leading to huge dipoles with excellent dielectric properties. Some of them (e. g., lysine and proline), have a solubility ≥ ${\ge }$ 10 m at ambient temperature. With an experimental characterization we prove that aqueous EDLCs based on electrolytes obtained with L‐ lysine or L‐proline added to 2 M NaNO3 solution have +50 % of gravimetric capacitance enhancement at low specific currents (0.1 A/g) compared to a reference device based on 2 M NaNO3 electrolyte without amino acids. A theoretical model suggests that this performance may be further enhanced by increasing the ionic accessibility of commercially available active materials, with porosity optimized to the size of amino acid ions. [ABSTRACT FROM AUTHOR]

The prosperous development of 5G technology requires the development of new high-performance microwave dielectric ceramics. MgZrNb 2- x (Ge 1/2 W 1/2) x O 8 (MZNGW) (0.02≤ x ≤ 0.08) ceramics were synthesized by the solid-state reaction with the high quality factor. The connection between the microstructure and microwave dielectric properties of MZNGW ceramics was systematically analyzed. Crystal structure refinement showed that MZNGW ceramics with monoclinic wolframite structure were synthesized in all samples. The sintering behavior and surface morphology indicate that doping of (Ge 1/2 W 1/2)5+ can improve the densification and promote the grain growth. The effect of (Ge 1/2 W 1/2)5+ doping on the phonon vibration can be obtained from Raman spectra, and the shift of Raman vibrational mode at 840 cm−1 and the change of half-height width have a great influence on the dielectric constant and quality factor. XPS spectra and AC impedance spectra are analyzed to show the influence of the crystalline defects on the macroscopic properties of the interlayer. The MgZrNb 1- x (Ge 1/2 W 1/2) x O 8 (x = 0.04) ceramic exhibits excellent microwave dielectric performance sintered at 1420 °C for 4 h: ε r = 27.1, Qf = 94,450 GHz, τ f = −41.65 ppm/°C, with great potential for applications in modern communications. [ABSTRACT FROM AUTHOR]

This study reports copolymer composition tailored wrapping of carbon nanotubes, leading to a gigantic dielectric permittivity and peculiar nonlinear rheological response in a nonfluoro copolymer/carbon nanotube (CNT) hybrid system. Specifically, we observed a strong interfacial polarization effect in ethylene vinyl acetate (EVAc) copolymer/CNT nanocomposites, resulting in a dielectric permittivity of approximately 4000 at 10 Hz and 450 (dielectric loss <1) at 1 kHz, with only 1% volume fraction of CNTs and 40% vinyl acetate (VAc) content. No such effect was observed in EVAc with 12% VAc. Extensive amplitude oscillatory rheology studies prompted us to propose a novel hook‐wrap‐type mechanism, wherein polar interactions act as hooks and nonpolar segments allow wrapping, depending on the optimal interactions between the CNT and copolymer. Raman spectroscopy, small‐angle x‐ray scattering, and relaxation studies also revealed a significant change in segmental dynamics and mass fractal compactness with a change in the VAc content. This work provides a melt processing‐based scalable route to develop polymer dielectrics while advancing the fundamental understanding of polymer‐CNT interactions and the underlying mechanisms of dielectric behavior in nanocomposites. [ABSTRACT FROM AUTHOR]

The present work investigates fluorescent polymer dispersion in the cholesteric liquid crystal (LC) as a function of temperature and concentration of polymer. The dielectric parameters of the cholesteric LC are determined by measuring capacitance and inductance with the function of the frequency and temperature. The material used for doping is a polymer‐poly[(4,4′‐hexafluoroisopropylidene) diphthalic anhydride‐alt‐3,6‐diaminoacridine hemisulfate] and it is one concentration doped in pure cholesteryl stearate. The temperature dependence of dielectric permittivity has been discussed for the pure and polymer‐doped system. In addition to this Fourier transform infra‐red (FTIR) spectroscopy has also been performed to understand the interaction between cholesteric LC and polymer molecules. [ABSTRACT FROM AUTHOR]

Dispersion of quantum dots (QDs) in liquid crystal (LC) medium can effectively modify their dielectric and electro-optical properties which can be useful in LC based display as well as non-display applications. Here, we reported the effect of doping of perovskite quantum dots (PQDs) on the dielectric properties of a nematic liquid crystal (NLC) material namely ZLI-1565 throughout its nematic and isotropic phases. The dielectric parameters of pure NLC and its composites with PQDs (0.1 wt.%, 0.25 wt.% and 0.5 wt. %) were observed in the frequency range of 20 Hz - 2 MHz. The value of dielectric permittivity (ɛ') and dielectric loss (?") increases in composites as compared to pure NLC in the low frequency region due to the increment in the mobile ion density. The spectral peak of loss factor (tan d) of pure NLC shifts towards the high frequency region with the addition of PQDs. Moreover, the temperature dependent dielectric parameters were also evaluated for pure NLC and 0.25 wt.% PQDs-NLC composite (i.e. optimum concentration). Moreover, the dielectric anisotropy and threshold voltage were also evaluated for pure sample and 0.25 wt.% composite. A point to be noted here that the clearing temperature (TN-I) of 0.25 wt.% composite is reduced by ?4 °C as compared to pure NLC. The results obtained on such PQDs-NLC composites could be utilized in the fabrication of NLC based electrical devices with tunable dielectric features. [ABSTRACT FROM AUTHOR]

In recent times, double perovskites have demonstrated promising potential as an alternative to address the instability and toxicity challenges associated with lead halide perovskites in optoelectronic applications. In this study, we successfully prepared Cs2MSbBr6 (M = Cu, Ag) double perovskite materials using the slow evaporation solution growth technique. The X-ray diffraction pattern confirmed the presence of the cubic phase in these synthesized materials. Furthermore, the optical analysis of Cs2CuSbBr6 and Cs2AgSbBr6 revealed their respective indirect bandgap energies to be 1.72 and 2.0 eV. The impedance spectroscopy technique was employed to investigate the properties of these materials, specifically double perovskites, across a frequency range of 10−1 to 106 Hz and at temperatures ranging from 303 to 403 K. To describe the AC conductivity, Jonscher's power law was utilized. The findings of the charge transportation study on Cs2MSbBr6 (M = Cu, Ag) indicate the existence of the non-overlapping small polaron tunneling mechanism in Cs2CuSbBr6, while the overlapping large polaron tunneling mechanism is observed in Cs2AgSbBr6. [ABSTRACT FROM AUTHOR]

In this study, elastomer composites, including silicone rubber and barium titanate, were fabricated by mechanical mixing, a low-cost, fast, and easy technique to produce highly dielectric materials. The resulting composites were investigated in terms of their dielectric and mechanical properties in terms of filler percentage in the mixture. Dielectric permittivity measurements were taken using the microwave regime, and uniaxial tensile tests were carried out for the study of the materials' mechanical properties, while combined experiments were also carried out to investigate potential correlations between them. The experimental results show that barium titanate inclusions in silicone matrix significantly improve the dielectric constant while reducing the mechanical properties of composites. In addition, combined experiments show that the composites exhibit a nearly stable dielectric profile under mechanical deformations. Consequently, mechanically mixed barium titanate–silicone elastomer composites could potentially become a cost-effective alternative in the extensive market for insulating materials and flexible electronics. [ABSTRACT FROM AUTHOR]

Ceramic dielectrics have been extensively studied due to their high-power density and fast charge/discharge rate. However, simultaneously increasing their dielectric permittivity and breakdown strength remains a formidable challenge. Here, the novel sandwich structure ceramic dielectrics are designed, in which monodisperse gold nanoparticles are sandwiched by two ceramic layers. The effects of gold nanoparticles with different sputtering times on the dielectric breakdown performance of the composite ceramics are investigated. The results show that the dielectric permittivity and breakdown strength of barium titanate composite ceramics with 3 min gold nanoparticle interlayer (BT-3Au-BT) reach 6017.5 (10 kHz) and 111.4 kV/cm, respectively, which are 9 % and 18 % higher than that of barium titanate ceramics without gold nanoparticle interlayer (BT-0Au-BT). The improved dielectric permittivity is originated from the formation of numerous micro-capacitors. The enhanced breakdown strength is attributed to the Coulomb blockade effect of gold nanoparticles. This work provides a novel, easy-to-operate and scalable approach for synergistically improving the dielectric permittivity and breakdown strength of dielectric materials, which opens up a novel way for the design of high-performance dielectric materials and would also be enlightening for the exploration of other functional nanocomposites. [ABSTRACT FROM AUTHOR]

The photodielectric effect in lead molybdate (PbMoO4) single crystals grown by the Czochralski method in a direction 30° off the a-axis in the plain (001) was studied. The charge was prepared from MoO3 and PbO α- or β-modifications. The reagents were taken both in a stoichiometric ratio and with excess of 0.5 mol % MoO3. The temperature dependences of the permittivity ε on samples illuminated with UV-light were measured in the temperature range of 290–700 K. Assumptions about the relationship between the magnitude of the photodielectric anomalies and the disorder of the PbMoO4 crystal lattice were made. [ABSTRACT FROM AUTHOR]

CaCu3Ti4O12 (CCTO) nanomaterials were synthesized using the low-cost facile sol-gel technique. X-ray diffraction (XRD) patterns confirmed the cubic structure of the prepared sample. Scherrer's formula and the W-H (Williamson-Hall) plot was used to calculated the average crystallite size of the prepared sample and it was found to be 27 nm and 31.3 nm, respectively, while the strain created in the lattice is 5.008 × 10−4. Based on the absorbance plot, the band-gap (Eg) of the sample was determined using Tauc's plot and it was found out to be 2.74 eV. The frequency dependence of dielectric permittivity (ε) and tangent loss (tan δ) of CCTO was analyzed at different temperature range from 300 K to 663 K over a frequency range from 10 Hz to 1 MHz. ε and tan δ decrease monotonically in entire frequency range and an anomalous frequency-dependent behavior was observed at different temperatures. High ε (in the range of 104) was found out at lower frequency range. Electrical conductivity was also analyzed in range of frequencies and temperature, it was found out that in higher region of frequency conductivity slightly increases. The room temperature values of ε, tanδ and conductivity was 7.5 × 103, 1.5 and 0.4 × 10−5 Ω−1 m−1, respectively. The reduction in Eg is achieved which was the major concern in this work. Furthermore, we have extensively studied the ε along with tan δ and ac conductivity for electronic application usage. According to these observations, CCTO is particularly prepared so that it could be suitable for microelectronic applications due to its high ε and low tan δ. [ABSTRACT FROM AUTHOR]

Polymer-stabilized cholesteric liquid crystal is one of the most coveted systems in the ever-expanding field of liquid crystal due to its wider potential application in smart windows, optical shutters, tunable lenses, etc. The dispersion of polymer into liquid crystal by introducing a small amount of chiral dopant prepared polymer-stabilized cholesteric liquid crystal. In this work, two samples of polymer- cholesteric liquid crystal were prepared. Surface treatment is applied on one composite while another sample is prepared without any treatment on the indium tin-oxide coated glass substrates. Frequency and temperature-dependent dielectric parameters are observed for both samples. The dielectric studies revealed that after surface treatment, the permittivity of the sample significantly increased. AC conductivity of the sample also increased. The photoluminescence spectra also show improvement in the intensity with the surface-treated sample. [ABSTRACT FROM AUTHOR]

Ferroelectric liquid crystals(FLCs), an exciting class of liquid crystals(LCs), found potential applications in the display as well as non-display regimes due to their fast response, low driving voltage and nonvolatile memory. The amalgamation of nanoparticles into FLCs has opened up new avenues in the LCs research field by alterations/modification of the existing properties of LCs. In this work, porous carbon nanoparticles (PCNPs) were dispersed into FLC mixture (W206E) and investigated their doping effect on FLC's textural, phase transition temperatures and dielectric studies in planar-aligned cells. Dielectric spectroscopy was carried out in the frequency range of 20 Hz to 10 MHz to explore the frequency as well as the temperature dependent of FLC in the entire SmC* region. The transition temperature of FLC mixture is increased by 4 °C in PCNPs doped FLC sample then undoped FLC sample. Nearly 8.42% increase in permittivity is observed. A Gold stone relaxation mode at ∼627 Hz was observed at lower frequency. [ABSTRACT FROM AUTHOR]

The solution-based casting method fabricates the free-standing pure PVDF-TrFE, PVDF-TrFE-Nafion blended films and tests them for structural, morphological, and microwave studies. The X-ray diffraction pattern and FTIR spectrum confirmed the formation of the ferroelectric β-phase of PVDF-TrFE. The surface morphology of blended films is studied by scanning electron microscope (SEM), and noticeable changes in the morphological features are observed in the blended films resulting from the differences in the nucleation process in these films. Then using the open-ended coaxial probe method, the complex permittivity measurements were carried out over a large frequency range, from 0.5 GHz to 50 GHz. These results were verified with the Transmission-Reflection method using a rectangular waveguide in the X-band and Ku-band frequency range. The microwave absorption properties of the blends are also studied in the same frequency range. The stability of the dielectric properties and low microwave absorption indicates that the blending of PVDF-TrFE with Nafion results in a new potential material for high frequency flexible capacitor applications. [ABSTRACT FROM AUTHOR]

Cobalt disulfide (CoS2) is a highly sophisticated metal chalcogenide that has garnered significant attention due to its distinctive properties such as its electrical, optical, catalytic, and magnetic capabilities and potential for use in a range of applications. In this work, pure CoS2 nanoparticles were synthesized using the economical and facile hydrothermal method. The X-Ray diffraction (XRD) method was used to characterize the synthesized sample, confirming that it has a cubic crystal structure with space group P a −3. The Debye-Scherrer's formula was implemented to determine the average crystallite size of nanoparticles and found to be 24.24 nm. Through the use of Field Emission Scanning Electron Microscopy (FESEM), the morphology and effective grain size of the obtained sample was determined. FTIR spectrophotometry was used to examine the vibrational stretching of the various bonds in CoS2. UV-Vis spectroscopy is employed to measure the optical property of the sample. The optical bandgap calculated from the Tauc Plot is around 1.90 eV reflecting the presence of photovoltaic properties in the sample. The change in dielectric permittivity and loss have been observed for the sample in the frequency range of 100 Hz to 10KHz at different temperatures between 303K and 423K. The frequency-dependent electrical conductivity of CoS2 is also explained. The observations revealed the presence of unique electrical and structural properties in the synthesized sample. [ABSTRACT FROM AUTHOR]

Complex permittivity spectra for D-sorbitol-water mixtures in the frequency range 10 MHz to 30 GHz have been determined over the entire concentration range using a time domain reflectometry (TDR) method. The complex permittivity spectra have been fitted to the Cole-Davidson relaxation model. The static dielectric constant and relaxation time were calculated from the complex permittivity spectra using the nonlinear least square fit method. The Kirkwood correlation factors were calculated. The theoretical dielectric constant for the mixtures has been calculated using the hydrogen bonding model suggested by Alenka Luzar. [ABSTRACT FROM AUTHOR]

Elastomers, as a typical category of soft dielectrics, have shown great potential for developing stretchable electronics and soft transducers. However, the performance of dielectric elastomers (DEs) is susceptible to the dielectric permittivity of the material, whether as insulators or actuators. On the other hand, experiments suggest that the material viscoelasticity significantly influences the dielectric permittivity of DEs. Based on the theory of finite-deformation viscoelasticity, this work adopts the Brillouin function to develop a modeling framework to examine the effect of material viscoelasticity on the dielectric permittivity for the first time. A comparison of the data fitting results between the models with and without consideration of the material viscoelasticity is presented. Simulation results also reveal that the viscous network of the elastomer exerts a mitigation effect on the decrease in the dielectric permittivity when the material is deformed. Furthermore, it is found that the loading rate is a key parameter that strongly affects the dielectric permittivity, mainly through the inelastic deformation. [ABSTRACT FROM AUTHOR]

The aim of this work was to synthesize and investigate the roentgenographic and electro-physical properties of new phases, namely double tellurites of neodymium. Oxotellurites of the composition NdMeIITeO4.5 MeII - Ca, Ba) were synthesized by the method of ceramic technology with high-temperature interaction of Nd2O3, TeO2 oxides with carbonates of alkaline earth metals in the interval of 800°C - 1200°C . Roentgenograms of the synthesized compounds were obtained using an Empyrean powder diffractometer by PANalytical and indication was determined using the X'Pert HighScore Plus program. It was found that the synthesized tellurites were crystallized in tetragonal syngony. The unit cell parameters, roentgen and pycnometric densities of the compounds were determined. It was revealed that with increasing ionic radii from Ca to Ba, the lattice parameters and unit cell volumes of synthesized tellurites increase. The assumed structure of the synthesized double tellurites of neodymium is a distorted perovskite structure. A study of the temperature dependence of the dielectric permittivity and electrical resistance of tellurites of neodymium-alkaline earth metals established that they can possess semiconducting properties at 293 K - 483 K. Temperature coefficients of resistance and forbidden zone width of tellurites were calculated. [ABSTRACT FROM AUTHOR]