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In this study, SiC/SiCN composites with BN interphase were prepared using chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis (PIP) methods. The evolution and related mechanisms of mechanical and microwave absorption properties of the composites after oxidation at 800 °C, 1000 °C, 1200 °C, and 1400 °C were investigated. The results showed that with the elevating of oxidation temperature, the flexural strength of SiC/SiCN composites gradually decreased, with a retention rate of 56.7 % after oxidation at 1400 °C. The main reasons for the deterioration of mechanical properties were the changes in the crystal structure of SiC fibers under high-temperature conditions and the formation of brittle SiO 2 phases on the surface and interior of the SiCN matrix. With the increase in oxidation temperature, the microwave absorption performance of the composites showed an enhancing trend. The main reasons were that after oxidation treatment, the reduction of free carbon content and the formation of SiO 2 film layers from the oxidation of SiC and SiCN led to a decrease in the complex permittivity of the composites, resulting in better impedance matching and dielectric loss capabilities. The contributions of BN interphase to stress dispersion, interface polarization, and oxidation protection significantly enhance the mechanical and electromagnetic absorption properties of the composites. Therefore, SiC/SiCN composites are high-temperature structural microwave absorbing materials with great application prospects. [ABSTRACT FROM AUTHOR]

This study investigates the simulation of electric field distribution and the characterization of Co3O4/carbon nanotube (CNT)-filled polyvinyl chloride (PVC) nanocomposites for potential applications in medium-voltage cables. The nanocomposites were prepared by incorporating Co3O4 nanoparticles and varying concentrations of CNTs (0, 0.1, 0.15, 0.20, and 0.25% by weight) into a PVC matrix. The UV–Vis spectroscopy revealed an absorption edge of 3.75 eV, a direct bandgap of 5.15 eV, an Urbach tail energy of 0.4594 eV, and a carbon cluster parameter of 44.617 for the PVC/Co3O4 + 0.25% CNT nanocomposite film. Incorporating CNTs enhanced the AC conductivity, dielectric constant, and dielectric loss compared to the pure Co3O4 sample. The highest AC conductivity (7.46 × 10–4 S/m) was achieved for the PVC/Co3O4 + 0.25% CNT nanocomposite. COMSOL Multiphysics simulations were performed to study the electric field distribution in medium-voltage cables made of PVC and PVC/Co3O4 + 0.25% CNT nanocomposites. The simulations revealed a more uniform electric field distribution in the nanocomposite cable than the pure PVC cable, owing to Co3O4 nanoparticles and CNTs. The novelty of this study is improved uniformity in the electric field distribution for medium-voltage cable applications. [ABSTRACT FROM AUTHOR]

NaNbO 3 -based glass-ceramics have garnered considerable attention owing to their high dielectric constant (ε r), low dielectric loss (tan δ), excellent chemical stability and tunable dielectric properties. Nonetheless, one major obstacle restricting the applications of NaNbO 3 -based glass-ceramics in energy-storage capacitors is their low breakdown strength (BDS) caused by interface polarization. In this work, the grains of glass-ceramics turn into fine and uniform from agglomeration via adding nucleating agent analogue HfO 2 to Na 2 O–Nb 2 O 5 –CaO–SiO 2 –B 2 O 3 (NNCBS–H) glass matrix. Thus, the long-range migration of space charge is frozen by the refined grains, which is conducive to diminishing the interfacial polarization of glass-ceramics. Moreover, the band gap energy (E g) of NNCBS-H glass-ceramics elevates from 3.21 eV to 3.30 eV with the incorporation of HfO 2 with wide band gap, enhancing its insulating performance. Ultimately, NNCBS-H4 glass-ceramics achieve a remarkable energy storage density (W rec) of 3.8 J/cm3, establishing an effective approach and precedent for developing glass-ceramic materials with high energy storage properties. [ABSTRACT FROM AUTHOR]

Research on high dielectric constant materials, such as zinc oxide (ZnO), has received significant attention due to their potential for modern microelectronics and high-density energy storage applications. However, the use of ZnO has been limited by its high dielectric loss. This study aims to reduce the dielectric loss of ZnO by investigating the effects of adding niobium oxide (Nb 2 O 5) on its electrical properties. Four compositions with varying amounts of Nb 2 O 5 (0, 0.5, 1, and 2wt%) were prepared. The disk samples were made via the pressing method and sintered at 1250 °C. In the sample with a high additive content, a secondary phase of ZnNb 2 O 6 was identified. The addition of Nb 2 O 5 resulted in substantial grain growth in the ZnO ceramic. The samples containing Nb 2 O 5 showed reduced electrical conductivity and increased electrical resistance. The sample with 2 wt% Nb 2 O 5 exhibited the lowest dielectric constant, dielectric loss, and electrical conductivity, along with the highest electrical resistance and ferromagnetic behavior. Particularly, this sample achieved an impressive dielectric constant of 52730 and a low dielectric loss of 0.32 at 1 kHz. This makes it a promising candidate for energy storage applications. [ABSTRACT FROM AUTHOR]

Pure and Na-doped ZnO thin films were deposited by sol-gel dip coating method on glass substrates with (2–10) wt.% Na dopant concentrations. XRD confirmed the hexagonal wurtzite structure oriented along the (101) plane. The variation in average crystallite size was observed due to Na doping (2-10 wt%) in ZnO crystal ranges between 14.85 nm and 17.88 nm. The increase in surface area from 9.63 cm2/g to 14.1 cm2/g and porosity was in the range of 34.51 %–56.1 % was observed. Optical properties showed that the band gap decreased with an increase in Na doping concentrations in ZnO films. Magnetic properties of all the thin films showed ferromagnetic behavior at ambient temperature. The hopping process explained the dielectric properties that were predicted by the Maxwell-Wagner model and Koop's theory. Dielectric constant and tangent loss decreased while the AC conductivity increased with an increase in Na doping concentrations. The electrochemical properties of Na-doped ZnO-based electrode materials were evaluated by using the galvanostatic potentiometer. The specific capacitance was observed in the range between 794.01 Fg-1 to 867.18 Fg-1. The Na-doped ZnO photocatalyst can effectively break down the methylene blue dye, making it helpful in treating wastewater pollutants. Insignificant antibacterial activity was displayed as the amount of Na doping in the ZnO increased. These are used as environmental protection and antibacterial agents in biomedicine. [ABSTRACT FROM AUTHOR]

In this work, Gadolinium (Gd3+) substituted Co–Cu–Cr (CCC) SFs with the chemical formula Co 0.5 Cu 0.5 Cr 0.5 Gd x Fe 1.5-x O 4 (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized via the self-combustion process. The single-phase matrix of the Gd3+ substituted CCC SFs was verified using X-ray diffraction (XRD). The crystallite size (D) of Gd3+ doped CCC SFs was reduced from 51.20 nm to 36.27 nm with increasing Gd3+ doping. The addition of Gd3+ in the CCC SFs lattice enhanced specific surface area (S) from 22.11 cm2/g to 28.57 cm2/g. The energy bandgap (E g) was increased from 4.83 eV to 5.40 eV and revealed an inverse relation with crystallite size. The tangent loss (tan δ), dielectric loss (ε ″), dielectric constant (ε ′), and ac conductivity (σ a c ) of Gd3+ doped CCC SFs exhibit frequency-dependent behaviour. The behaviour of these dielectric properties has been analyzed using both Koop's theory and the Maxwell-Wagner model. Moreover, it was found that the ε ′ was enhanced, while σ a c and tan δ w as reduced with the doping of Gd3+ in CCC SFs. The saturation magnetization and microwave operating frequency were increased with the doping of Gd3+ in CCC SFs. Because of their diverse dielectric and magnetic properties, the Gd3+ doped CCC SFs have considerable potential for different applications, including microwave absorption materials, switching high-frequency devices, and microwave frequency-operating devices. [ABSTRACT FROM AUTHOR]

This study focuses on examining how the rare-earth cerium incorporation affects the magnetic, dielectric, and mechanical characteristics of Ni 0.5 Mn 0.25 Co 0.25 Ce x Fe 2-x O 4 spinel ferrite nanoparticles. (NMCCF). The nanoferrite Ni 0.5 Mn 0.25 Co 0.25 Ce 0.04 Fe 1.96 O 4 acquires the lowest coercivity of 567 Oe and the highest saturation magnetization of 52.23 emu/g. All the NMCCFx nanoferrites exhibit a microwave frequency range of 9.47–11.55 GHz, suggesting potential applications in longitudinal recording media and microwave absorbance. Moreover, the nanoferrite Ni 0.5 Mn 0.25 Co 0.25 Ce 0.1 Fe 1.9 O 4 demonstrates the highest dielectric value of 1871, with an enhancing ratio of 754 %, excellent conductivity at 3.12 μ(Ω.m)−1 along with a remarkably enhanced percentage of 369 %. Additionally, it shows a loss factor of 2.17, with a notable improvement percentage of 26 % compared to the pure NMCCF0 sample at 50 Hz and room temperature. The elastic moduli (longitudinal, shear, Young, and bulk) of the Ni 0.5 Mn 0.25 Co 0.25 Ce 0.1 Fe 1.9 O 4 nanoferrite increased from 1.21 to 2.77 GPa, 0.25–0.76 GPa, 0.68–1.99 GPa, and 0.87–1.75 GPa, respectively. This study introduces a novel approach to Ni–Mn–Co–Ce spinel nanoferrites, highlighting their magnetic, electrical, and mechanical characteristics, which hold promise for electronic and high-frequency device applications. [ABSTRACT FROM AUTHOR]

Composite material based on polyethylene glycol (PEG) and polypyrrole (PPy) polyrotaxanes both encapsulated into α‐cyclodextrins (α‐CDs) macrocycle molecules was synthesized by cross‐linking reaction. The effect of PPy‐αCD polyrotaxane incorporation into the PEG‐αCD polyrotaxane matrix, on the structural, morphological, thermal, and dielectric properties was evaluated and compared to the reference material. Scanning electron microscopy spectroscopy indicates different surface morphologies of this material in comparison to the reference one. In addition, the contact angle measurements and surface free energy attest a hydrophilic surface, while the reference material exhibits a hydrophobic surface. More than that, the presence of the PPy‐αCD cross‐linked into the matrix has a beneficial effect on the thermal properties. The composite material shows an enhanced dielectric constant value of 31,365 at 10 Hz frequency compared to the 38.2 of the reference material, and higher dielectric loss (62,398 vs. 80 at 10 Hz, respectively). The conductivity measurements at 10 Hz frequency indicated for the reference material the value 4.5 × 10−11, while for the material with PPy‐αCD polyrotaxane, the conductivity is three orders of magnitude higher (3.5 × 10−8) confirming the improvements of the electrical properties. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) has the advantages of corrosion resistance, easy processing, and low dielectric loss, but its low thermal conductivity limits the application of its composites in fields such as electronic packaging. To solve this problem, in this work, composite microspheres with the segregated structure were prepared by coating boron nitride nanosheets (BNNSs) on the PP surface by Pickering‐like emulsion method, and BNNSs@PP composites with three‐dimensional thermal conductivity network were obtained after molding. Due to the high thermal conductivity of BNNSs and the formation of perfect thermal conduction pathways, the thermal conductivity of the composites reached 1.71 W m−1 K−1 when the content of BNNSs was 10.1 wt%, which was a 713% increase in thermal conductivity for that of pure PP. At the same time, the mechanical properties of the composites were ensured. This method provides a simple and effective technique to improve the thermal conductivity of PP‐based thermally conductive composites, which has a wide application potential in electronic packaging. [ABSTRACT FROM AUTHOR]

Single-crystal samples of the 3R-CuCrO2 phase (R3m, a = 2.9613(2) Å, c = 17.098(2) Å) with a delafossite structure were grown by the flux method. Structural parameters were refined by X-ray structural analysis. The elemental composition of the grown crystals was confirmed by Auger electron spectroscopy. A threshold electric field switching effect from a high-resistance to a low-resistance state was discovered. The effect is characterized by a jump in electrical resistance (up to 5 orders of magnitude at E = 4.7 kV/cm, T = 120 K) and S-shaped current–voltage characteristics with a region of negative differential resistance. The temperature dependences of dielectric permittivity and dielectric loss tangent exhibit a Debye-type relaxation process with an activation energy of 0.51(3) eV. The observed features of dc conductivity, current–voltage characteristics, and dielectric properties interpreted on the basis of the existence of charge carriers in a small polaron state and the destruction of this state by the electric field. [ABSTRACT FROM AUTHOR]

To improve the dielectric properties and corona resistance of epoxy resins (EPs), the authors designed and synthesized Si‐B‐Mg/EP nanocomposites and investigated the effects of varying the magnesium elemental content on the dielectric properties, breakdown field strength, corona resistance life, volume resistivity and conductive current of Si‐B‐Mg/EP nanocomposites. The experimental results show that when the molar ratio of Si, B, and Mg in the Si‐B‐Mg composite oxide is 18:2:0.125, the composite has the minor dielectric loss and the most extensive corona resistance life of 401.8 min, which is 4.6 times that of the pure EPs. From the experimental results, the introduction of magnesium can effectively improve the dielectric loss and corona resistance of Si‐B‐Mg/EP composites. Highlights: Si‐B‐Mg composite oxides were designed and synthesized.Performance analysis of Si‐B‐Mg/EP composites with different magnesium contentThe introduction of magnesium reduces the dielectric loss of composites.The introduction of magnesium improves the corona resistance life of composites.Si‐B‐Mg/EP composites with both low dielectric loss and high corona resistance. [ABSTRACT FROM AUTHOR]

Highlights Tailoring the interfacial structure is a critical approach for modulating the dielectric characteristics of nanocomposites. Herein, the energy storage properties of polyimide/silica (PIS) were improved by grafting 4‐carboxyphenyl (PhCOOH), 4‐aminophenyl, isocyanate, phenyl and amino groups on the interfaces. The results demonstrated that the PhCOOH groups not only optimized the interfacial structures, but also enhanced both the relative dielectric permittivity (εr) and dielectric strength (Eb) of PI‐based films. The PhCOOH endowed the PI‐based films with high εr by elevating the intrinsic polarization and suppressing the relaxation polarization. Moreover, the PhCOOH elevated charge injection barriers and reduced carrier hopping distances, resulting in a lower current density. Molecular simulations revealed that the PhCOOH raised the SiO2 electron affinity and the trap depth of PIS composites, achieving the enhancement of Eb. The PIS‐PhCOOH films with high εr (7.57, 103 Hz) and Eb (421 kV⋅mm−1) exhibited superior discharge energy density (6.20 J⋅cm−3) and energy storage efficiency (88.80%), which was 119.08% higher than that of PIS (2.83 J⋅cm−3, 75.91%). This work provides insights into interface engineering to synergistically improve dielectric permittivity and dielectric strength of polymer‐based composites, paving the way for fabricating high‐performance dielectrics. Polarization response were modulated by interface modification. Both permittivity and dielectric strength of PI‐based films were enhanced. PI‐based films showed an energy density as high as 6.20 J⋅cm−3. [ABSTRACT FROM AUTHOR]

AbstractNanocomposites (NC) of amorphous polycarbonate (PC) and cerium oxide (CeO2) nanoparticles (NPs) were prepared. The synthesized CeO2 had a nanonature of average particle size 22 nm, as indicated from their high resolution transmission electron microscopy images (HTEM). Samples of the PC/CeO2 NC films were irradiated with several γ ray doses (10-80 kGy). The resultant outcome of the γ irradiation on the optical properties of the NC films was studied using ultraviolet spectroscopy (UV-vis). Upon raising the γ ray dose up to 80 kGy, the maximum dose used, the direct bandgap decreased from 4.92 to 3.91 eV. The Urbach energy showed an opposite trend; it increased from 0.46 to 0.92 eV. This could be attributed to the domination of chain crosslinks. Also, the optical dielectric loss (ε”) assisted in identifying the nature of the microelectronic transitions. It was found that the PC/CeO2 NC films had direct allowed transitions. Additionally, the γ induced changes in the optical conductivity were studied. Moreover, the optical color changes between the pristine and the irradiated films were evaluated. The pristine NC film was uncolored. It showed significant color changes when irradiated with γ radiation up to 80 kGy. The induced modifications in the optical properties suggest that the γ radiation is an effective means for modifying the properties that allows the use of PC/CeO2 NC in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) offers a novel approach for converting high‐entropy mechanical energy into electrical energy, yet achieving high charge density remains critical. Optimizations using dielectrics with high specific capacitance have mitigated air breakdown, but charge loss within dielectrics persists as a limiting factor. Here, based on poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF‐TrFE‐CFE)) with high specific capacitance, (P(VDF‐TrFE‐CFE)) composites’ trap density and energy are engineered using high‐polarity interfaces from barium titanate (BTO) nanoparticles and dense chain segment stacking induced by electrostatic interaction with polyetherimide (PEI) to enhance charge retention capability. With modified high interfacial traps, an ultrahigh charge density of 9.23 mC m−2 is achieved in external charge excitation (ECE) TENG using 0.2 vol% PEI/P(VDF‐TrFE‐CFE) film, marking the highest charge density reported for single‐unit TENGs. This work provides novel material strategies for high‐performance TENGs, paving the way for their large‐scale practical applications. [ABSTRACT FROM AUTHOR]

Herein, the influence of Cr3+ dopant on the structural, morphological, optical, photocatalytic, dielectric and magnetic properties of ZnO was investigated for various applications. Pure ZnO and Cr3+ doped ZnO nanoparticles were synthesised by green mediated approach. The synthesised nanoparticles examined by using XRD, SEM, EDX, FTIR, PL, UV–Vis spectroscopy, dielectric and magnetic analysis. XRD confirmed the wurtizte hexagonal structure of synthesised samples and also revealed that the Cr didn't alter the structure of host ZnO. The FTIR analysis revealed the presence of Cr ions in ZnO structures. Doping of Cr ions improved the optical absorbance of ZnO and the optical band gap showed the blue shift with increasing concentration of Cr. The synthesised Cr doped nanoparticles show the outstanding photocatalytic efficiency under solar irradiation against MG pollutant dye. The dielectric constant (ε) improves and dielectric loss (tan (δ)) reduces at lower frequencies with increasing content of Cr. The AC conductivity for doped nanoparticles showed the increasing trend, especially for 4.5 % Cr doped ZnO nanoparticles. The ferromagnetic behavior at room temperature of Cr doped ZnO nanoparticles confirmed by VSM. The obtained results from all investigations make the Cr doped ZnO samples a potential choice for various applications such as, spin based electronic devices and energy storage devices. [ABSTRACT FROM AUTHOR]

Gadolinium-substituted cobalt manganese ferrite nanoparticles with the composition Co 0.6 Mn 0.4 Gd x Fe 2- x O 4 (where x ranges from 0.0 to 0.08, with x = 0.02) were prepared through the sonochemical method. X-ray diffraction reveals that grown samples are single-phase cubic spinel belonging to space group Fd 3 m, where the crystallite sizes decrease with increasing Gd3+ content. At high doping ratios (x > 0.06), there was a slight increase in crystallite size compared to that of pure Co–Mn ferrite (x = 0), while the lattice parameter (a) decreased in the low doping range of Gd (x < 0.06), resulting in a reduction in crystallite size. Bertaut's method confirms that 80 % of the tetrahedral (A) sites were occupied by Mn ions, while the remaining sites were occupied by other cations in the octahedral (B) positions. Gd3+ ions were found exclusively in the octahedral-B sites. Co2+ ions were expected to occupy the octahedral-B site, which was confirmed in this study for the x = 0.0 and 0.02 samples. Field emission scanning electron microscopy shows the samples are agglomerated and have dense structures. Fourier transform infrared and Raman spectra validated the presence of spinel ferrite modes. Dielectric investigations indicate that as the Gd3+ content exceeds x = 0.0, the dielectric constant and dielectric loss decrease at lower frequencies. The observed dielectric behavior exhibited typical dispersion patterns attributed to Maxwell-Wagner polarization. Furthermore, changes in dielectric properties were observed as the Gd3+ content in Co 0.6 Mn 0.4 Gd x Fe 2- x O 4 nanoparticles increased, which can be attributed to the presence of oxygen vacancies and variations in the distribution of Fe3+ ions at both A and B-sites. [ABSTRACT FROM AUTHOR]

High dielectric constant (ε), thermal conductivity (TC), and breakdown strength (Eb) along with low loss flexible polymeric nanocomposites display multifunctional applications. In this work, to synergistically bolster the TC and Eb while restraining dielectric loss and leakage current in the percolating flaky copper (f‐Cu)/poly(vinylidene fluoride) (PVDF), presenting a giant ε, the core@shell structured f‐Cu@MgO (magnesium oxide) nanosheets were first created via a chemical precipitation method, then incorporated into host PVDF to explore the MgO shell' impact on the TC and dielectric properties of the resulting nanocomposites. The introduced MgO interlayer strengthens the interfacial interactions and significantly mitigates the interfacial mismatch in both ε and conductivity between the f‐Cu and PVDF, resulting in elevated TC and Eb of the f‐Cu@MgO/PVDF in comparison to pristine f‐Cu/PVDF. Furthermore, the insulating MgO interlayer introduces deep traps and inhibits the long‐distance migration of electrons, leading to remarkably suppressed dielectric loss. More importantly, the TC and dielectric properties of nanocomposites can be optimized by tuning the MgO thickness. The fitting results via the Havriliak‐Negami equation theoretically support the MgO shell's suppression effect on charge migration and reveal the underlying polarization mechanism in the nanocomposites. The developed nanocomposites with currently high ε, Eb and TC but low loss, present promising applications in electrical power systems. [ABSTRACT FROM AUTHOR]

The sol-gel approach prepared Sr-doped BiFeO3 samples using citric acid as fuel. The structure, lattice dynamics, magnetization, and dielectric properties have all been studied using various techniques, including the LCR meter for dielectric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and vibrating sample magnetometer (VSM). X-ray diffraction (XRD) analysis of powdered Sr-doped BiFeO3 shows the formation of a pure BiFeO3 rhombohedral structure of the perovskite-type. The FESEM micrograph shows the morphology of the pallets of the samples unaffected by Sr doping at low concentrations. Vibrational modes surrounding the Fe–O–Fe stretching bonds are briefly described by FTIR spectra in transmittance mode. Moreover, it has been found that at room temperature, the dielectric constant and dielectric loss tangent of the samples, evaluated in the frequency range of 100–107 Hz, decrease significantly. The magnetic investigation results indicate that the saturation magnetization is slightly enhanced with an increased concentration of Sr2+. The pristine BiFeO3 had the lowest remanent magnetization value. The ions' saturation magnetization and remanence magnetization values reached 1.85 emu/g and 0.88 emu/g, respectively, at x = 0.25. [ABSTRACT FROM AUTHOR]

This work demonstrates the fabrication, characterization, and energy storage capacity of high calcium-doped strontium titanate thick films (Sr0.60Ca0.40TiO3) for the first time. The thick films were fabricated using the screen-printing technique and densified using uniaxial pressing. The effect of densification on the structural, morphological, and surface chemical compositional of the materials was studied. The densified thick film revealed a notable frequency stability of dielectric permittivity (ε′) ≈ 198 with a low dielectric loss tangent (tanδ) in the order of 10− 3 between 100 Hz and 1 MHz and was characterized by slim P-E loops signifying its paraelectric nature. A high energy recovery density (Ue) of 4.1 J/cm3 and a high energy efficiency of 96% were simultaneously reached. [ABSTRACT FROM AUTHOR]

To quickly achieve nondestructive detection of protein content in fresh milk, this study utilized a network analyzer and an open coaxial probe to analyze the dielectric spectra of milk samples at 100 frequency points within the 2–20 GHz range, focusing on the dielectric constant ε' and the dielectric loss factor ε''. Feature variables were extracted from the full dielectric spectra using the successive projections algorithm (SPA), uninformative variables elimination (UVE), and the combined UVE‐SPA method. These variables were then used to develop partial least squares regression (PLSR), support vector machine (SVM), decision tree (DT), random forest (RF), and least squares boosting (LSBOOST) models for predicting protein content. The results showed that ε' decreased monotonically with increasing frequency, while ε'' increased monotonically. The UVE‐SPA method for feature extraction demonstrated superior performance, with the UVE‐SPA‐PLSR model being the best for predicting milk protein content, achieving the highest RC2 = 0.998 and RP2 = 0.989 and the lowest RMSEC = 0.019% and RMSEP = 0.032%. This study provides a theoretical reference for evaluating milk quality and developing intelligent detection equipment for natural milk. [ABSTRACT FROM AUTHOR]

Polymer composites with low dielectric properties and excellent radio transparency are essential for high signal transmission rates and high device integration. However, creating dielectric polymer composites with high radio transparency is a challenging task. This work presents comparative results of studying the dielectric loss, permittivity and radio transparency of composite materials, such as aramid-epoxy composite (AEC), glass fiber (GF), carbon fiber reinforced plastic (CFRP), and ultra-high molecular weight high-density polyethylene (UHMWPE). Based on the experimental results, the following transmission percentages were established for various materials: CFRP – 2.45%, AEC – 79.43%, UHMWPE – 80.16%, and GF – 78.88%. The dielectric loss tangent angle of carbon fiber is significantly higher compared to other polymer composites, UHMWPE exhibits the lowest tangent angle values, and AEC and GF have stable and low dielectric loss. The obtained polymer composites demonstrated low dielectric permittivity values: AEС 2.9, UHMWPE 2.56, and GF 3.64. [ABSTRACT FROM AUTHOR]

To confer light‐blocking properties upon the Al2O3 encapsulation material, this study employed a one‐step method using α‐Al2O3 as the main raw material to synthesize CaCu3Ti4O12(CCTO)–MnO2–Co2O3 series black Al2O3 ceramics. The research investigated their coloring effect, sintering behavior, dielectric, and mechanical properties. The results indicate that the CCTO–MnO2–Co2O3 series colorants successfully dyed the Al2O3 ceramics black, while their introduction resulted in the formation of various spinel‐type compounds and facilitated the sintering of Al2O3 ceramics. The sintering mechanism and performance effects of black Al2O3 ceramics were thoroughly investigated, revealing that with an increase in the colorant content, all properties of the samples improved. When the colorant content reached 15.0 wt.%, the coloring effect reached its optimum, with a relative density of 96.7%, a dielectric constant of 12.5, a dielectric loss of.0081, a flexural strength of 314.4 MPa, and a Vickers hardness of 1254.5 Hv. [ABSTRACT FROM AUTHOR]

Borosilicate glass is a promising material for 3D system integration technology due to its high integration and adjustable CTE (coefficient of thermal expansion). However, the structure and composition of borosilicate glasses result in a relatively high melting point and dielectric loss, which hinders the wide application of such glasses. In this study, we analyze the relationship between different Ba/Sr ratios and the structure and properties of the glass. We determine and further analyze the effect of mixed alkaline earth effect on the proportion of the Qn unit, [BO3], and [SiO4] in the glass structure, and consequently, its influence on the dielectric properties. Alkaline earth metals act as network-modifying ions to reconnect the interrupted network of the glass, stabilizing the glass structure and reducing the polarization loss of the glass. Raman analysis showed that the Raman spectrum shifted towards higher frequencies as the ratio of Al 2 O 3 /RO increased, with the Raman bands at 1300 cm−1-1500 cm−1 almost disappearing, while the Raman area at 730 cm−1-830 cm−1 increased. This indicated that the [BO3] units formed a ring structure in the glass, thereby enhancing the compactness of the glass network. The thermal expansion coefficient was 4.09 ppm K−1 when the Ba/Sr ratio was 1:1, and the dielectric constant and dielectric loss were 4.3 and 1.24 × 10−3, respectively. Overall, the dielectric properties and thermal expansion coefficients of the glass can be effectively reduced by doping with alkaline-earth metals, making the borosilicate glass more suitable for three-dimensional integrated system packaging. [ABSTRACT FROM AUTHOR]

While two-dimensional lamellar materials, specifically Ti 3 C 2 T x MXenes, have shown great promise as wave-absorbing materials, the precise design of interlayer spacing poses a persistent challenge. In this study, Ti 3 C 2 T x MXene layers with adjustable interlayer spacings were crafted using a straightforward molecular welding technique. Through the incorporation of Ni nanoparticles onto the Ti 3 C 2 T x MXene layers using a combination of simple mechanical stirring and carbonation reactions, we successfully developed Ti 3 C 2 T x MXene/Ni/C composites featuring a distinct lamellar structure. A uniform dispersion of Ni nanoparticles on the surface of the Ti 3 C 2 T x MXene nanosheets was found with some of the nanoparticles intercalated into the layers. The Ti 3 C 2 T x MXene/Ni/C composites exhibited a maximum reflection loss (RL) value of −42.3 dB at 12.3 GHz, accompanied by an impressive effective absorption bandwidth (EAB) of 5.6 GHz. This outstanding absorption performance could be attributed to various factors, including the dielectric loss of the Ti 3 C 2 T x MXene lamellae, reflections and scattering of multiphase heterostructures, the magnetic loss of the Ni nanoparticles, and their synergistic attenuation. Furthermore, Ni nanoparticles with high electrical conductivity induced vortex currents under the alternating influence of electromagnetic waves (EMWs), resulting in a substantial depletion. This study introduces an innovative approach for synthesizing Ti 3 C 2 T x MXene/Ni/C composites with tunable interlayer spacing, showing their potential for applications in microwave absorption (MA). [ABSTRACT FROM AUTHOR]

Porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics are anticipated to serve as high-temperature wave-transparent materials, yet the fabrication of high-performance porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics remains a significant challenge. Addressing this issue, this study introduces a technique for crafting high-performance porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics. This method involves the homogeneous blending of SiO 2 and Si 3 N 4 powders, followed by digital light processing and high-temperature liquid-phase sintering at 2000 °C. The impact of SiO 2 content on various properties of the ceramic slurry and the resultant ceramics was thoroughly examined, including rheology, curing depth, microstructural morphology, phase composition, flexural strength, hardness, dielectric constant, and dielectric loss. It was observed that a SiO 2 content of 30 % enables the slurry to fulfill the criteria for digital light processing, leading to the production of porous β-Si 3 N 4 /Si 5 AlON 7 composite ceramics that exhibit outstanding mechanical and dielectric properties. Specifically, these ceramics demonstrated a flexural strength of 149.2 ± 7.2 MPa and a hardness of 11.8 ± 1.1 GPa. Moreover, at a frequency of 10 GHz, the ceramics exhibited a dielectric constant of 4.02 and a dielectric loss of 0.11, highlighting their potential as high-temperature wave-transparent materials. [ABSTRACT FROM AUTHOR]

The samples including Li 0.1 Co 0.8 Fe 2. 1 O 4 (LCFO) spinel ferrite (SF) and LCFO SF/graphene oxide (GO = 10 wt%, 15 wt%, and 20 wt%) nanocomposite were fabricated via the self-ignition route by following the bath ultra-sonication method. Their structural, morphological, and compositional properties were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray (EDX) spectroscopy, respectively. Moreover, the dielectric and magnetic properties at 300 K were studied using an impedance analyzer (IA) meter and vibrating sample magnetometer (VSM), respectively. All LCFO SF and GO-based LCFO nanocomposites exhibited a pure spinel matrix. The crystallite size was increased by the GO addition in the LCFO SF sample. The morphological analysis showed the non-uniform distribution of particles. The dielectric constant and loss exhibited behaviour consistent with Maxwell-Wagner interfacial polarization. The low tangent loss was observed at high frequency and ac conductivity analysis was increased with increasing the GO content. A slight enhancement in saturation magnetization was observed at 300 K with the addition of GO in LCFO SF. Hence, doping with GO offers a means to tune the dielectric, and magnetic response of the LCFO SF sample and is the best candidate for potential high-frequency application. [Display omitted] • The LCFO SF and LCFO/GO nanocomposites were prepared via the self-ignition route with an ultra-sonication technique. • The crystallite size was increased from 30 nm to 54 nm. • FTIR analysis along with XRD analysis also confirmed the spinel matrix. • SEM and TEM micrographs indicated the non-uniform distribution and agglomeration with the increasing GO. • The increase in GO leads to an improvement in the dielectric response. • The saturation magnetization was increased with the addition of GO. • The combination of LCFO SF with GO enhanced the dielectric, and magnetic properties, offering a candidate for high-frequency applications. [ABSTRACT FROM AUTHOR]

This paper focuses on improving the electrical properties of 0.4CaBi 2 Nb 2 O 9 -0.6Na 0.5 Bi 2.5 Nb 2 O 9 piezoelectric ceramics through Gd doping. The effect of Gd3+ replacing Ca2+ and Na+ on the 0.4CaBi 2 Nb 2 O 9 -0.6Na 0.5 Bi 2.5 Nb 2 O 9 (0.4CBN-0.6NBN) piezoelectric ceramics was subjected to a comprehensive examination. The introduction of Gd3+ has led to the development of a pseudo-tetragonal phase, enhancing the polarization and strengthening the piezoelectric effect. Among the 0.4CBN-0.6NBN- x Gd (x = 0.00–0.05) ceramic samples, the sample at x = 0.03 that exhibits the best piezoelectric properties demonstrates a high Curie temperature of 849.7 °C, low dielectric loss (tan δ) of 1.295 % (at 550 °C), high DC resistivity (ρ DC) of 1.58 × 108 Ω‧cm (at 500 °C), and a high d 33 value of 17.3 pC/N. Following annealing at 800 °C, its d 33 retains 94.2 % of its initial value. The improved electrical performances indicate that the Gd-doped 0.4CBN-0.6NBN ceramics hold a great deal of promise for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

Decorating the CNTs with dielectric loss material is an effective means of enhancing electromagnetic wave absorption properties. In this work, we synthesized high dielectric loss NiCo 2 O 4 nanoparticles on CNTs through hydrothermal method. By adjusting hydrothermal time, the NiCo 2 O 4 /CNTs with different NiCo 2 O 4 content were obtained. The nucleation and growth of NiCo 2 O 4 nanoparticles would cause a lot of defects and heterogeneous interfaces on CNTs, which influences the conduction loss and polarization loss of CNTs. Therefore, adjusting the content of NiCo 2 O 4 in CNTs is an efficient path to enhance its absorbing performance. When the content of NiCo 2 O 4 is 45.05 wt%, the reflection loss of NiCo 2 O 4 /CNTs reaches −43.2 dB, and the effective absorption bandwidth can be up to 3.3 GHz. It proves that NiCo 2 O 4 /CNTs has potential to be a high quality absorbing agent. [ABSTRACT FROM AUTHOR]

Inorganic oxide ceramics are essential for microwave applications due to their stable structure and exceptional performance. LiZnMgGaTi 2 O 8 ceramics were prepared using the solid-phase method. XRD and TEM confirmed that the ceramics possess spinel structures. The ceramics had a maximum relative density of 94.57 % and a Vickers hardness of 8.58 GPa when sintered at 1220 °C. The ionic polarizability of Ti4+ in the ceramics exceeds the Shannon value, leading to a 20.3 % deviation between ε th and ε r. The activation energy of the impedance spectrum fitting is 1.302 eV, indicating a low concentration of oxygen vacancies in the ceramic. Hence, the Q × f value of the ceramics is primarily influenced by relative density. The optimal microwave dielectric properties of LiZnMgGaTi 2 O 8 ceramics are ε r = 15.68, Q × f = 66,620 GHz, and τ f = −30.9 ppm/°C. The test curves of ε r and dielectric loss remain nearly parallel to the x-axis from −80 °C to 80 °C, demonstrating the excellent stability of LiZnMgGaTi 2 O 8 ceramics. [ABSTRACT FROM AUTHOR]

Dielectric elastomers with conducting inorganic fillers offer a wide range of uses, including capacitive energy storage, elastomer sensors, actuators, and many more. In this approach, low dielectric loss and high dielectric constant may be made possible by ternary composites that use metal alloy components as reinforcing fillers. Here, Cu-based alloy was added to acrylonitrile-butadiene rubber (NBR) to produce ternary rubber composites. Unfortunately, the Cu–Al–Zn alloy's material incompatibility with the rubber matrix typically leads to phase separation, void formation, and particle aggregation, all of which have a dramatic negative impact on performance. Using 3-(trimethoxysilyl)propyl methacrylate as a coupling agent, Cu–Al–Zn alloy particles were uniformly dispersed onto the NBR rubber matrix through surface modification. By using scanning electron microscopy, the appropriate reinforcement of modified Cu-based alloy particles into NBR was carefully examined. The effect of modified Cu–Al–Zn alloy loading on the swelling behavior of the composite was also investigated. The findings show that the shape and dispersion state of modified Cu–Al–Zn alloy were important for the dielectric characteristics of the NBR compounds. By adding reinforced modified Cu-based alloy to the NBR matrix, mechanical characteristics were significantly improved. The uniform dispersion of modified Cu–Al–Zn alloy particles and strong interfacial compatibility with rubber matrix are the reasons for the outstanding performance of NBR composites, which suggests high-performance dielectric composite. [ABSTRACT FROM AUTHOR]

The novel double perovskite oxide SrEuTiFeO6 was synthesized using the solid‐state reaction method. X‐ray diffraction analysis, complemented by Rietveld refinement, confirmed that this material crystallizes in a cubic double perovskite structure with the Pm3̅m space group and revealed cationic disorder at both the A (Sr, Eu) and B (Ti, Fe) sites. Crystallite size and lattice strain were determined through various methods. Fourier‐transform infrared spectroscopy was utilized to examine vibrational modes and bond distortions within this material. Scanning electron microscopy showed a heterogeneous microstructure, with a wide distribution of grain sizes and shapes, resulting from the kinetics of the solid‐state synthesis. Energy dispersive X‐ray spectroscopy confirmed the material's homogeneity, stoichiometry, and chemical composition. UV–visible spectroscopy was used to investigate the optical properties of SrEuTiFeO6, identifying several characteristic optical transitions. The band gap energy and refractive index were found to be 2.08 eV and 2.60, respectively, indicating the material's potential for various applications. Additionally, the dielectric properties, including the relative dielectric constant and loss tangent, were thoroughly analyzed as functions of frequency and temperature. The electrical conductivity dispersion phenomenon was also analyzed according to Jonscher's power law, revealing the predominance of overlapping the large polaron tunneling mechanism. [ABSTRACT FROM AUTHOR]

High‐performance piezoelectric ceramic materials are required for piezoelectric sensors under harsh conditions in nuclear power plants, aeronautics, and aerospace. In this work, a lead‐free high‐Curie‐temperature (TC ∼792°C) Aurivillius‐type sodium bismuth niobate, Na0.5Bi2.5Nb2O9 (NBN), was fabricated through spark plasma sintering (SPS). The textured NBN ceramics with a high orientation factor of 83% exhibit significantly enhanced piezoelectric performance with a piezoelectric constant d33 of 31.2 pC/N, three times higher than that of nontextured NBN (d33 ∼ 11.6 pC/N). More importantly, the textured NBN ceramics maintain excellent electrical properties at high temperature, with a high in situ d33 of 35.9 pC/N, very low dielectric loss tanδ = 2.5% (@ 100 kHz) and high dc electrical resistivity ρ of 7.5 MΩ cm at 500°C. These results suggest that the textured NBN ceramics are good high‐temperature piezoelectric ceramic materials, and have promising applications in the field of high‐temperature piezoelectric sensors. [ABSTRACT FROM AUTHOR]

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This study investigates the potential of Plasma-Activated Water (PAW) technology for the production of nitrate fertilizer, focusing on the dielectric properties of plasma-treated water, such as the dielectric constant and dielectric loss factor. The research aims to elucidate the impact of plasma treatment and varying water flow rates on these properties. An experimental approach was employed wherein ion-free water was subjected to plasma treatment at different flow rates (0.5, 1.0, and 2.0 L/min) and durations (1, 2, and 3 h). The results reveal a marked enhancement in the dielectric properties of the water following plasma treatment, with the most significant improvements observed at a flow rate of 0.5 L per minute and a treatment duration of 3 h, and dielectric efficiencies of 97.82%, 97.21%, and 96.61% achieved at flow rates of 0.5, 1.0, and 2.0 L/min, respectively. These findings demonstrate that PAW technology enhances the efficiency of nitrate fertilizer production by optimizing energy storage and reducing energy losses. The study underscores the potential of PAW as a sustainable, environmentally benign alternative to conventional chemical fertilizers, contributing to more efficient and sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

The article presents the results of the study of radiotransparent celsian ceramics, in which part of the components were introduced using eutectic glass of the pseudoternary BaO– AI2O3-SiO2 system. The bonding of the components of the experimental glass into the celsian phase was realized according to the principle of reactive structure formation by adding the missing components (crystalline fillers). In this case, the obtained dense sintered water-resistant ceramic, the only crystalline phase in the composition of which is the monoclinic form of celsian, which forms a microhomogeneous structural matrix of the material. Celsian is represented by distinct prismatic crystals of tetragonal and hexagonal shape. The size of celsian crystals increases from 3–5 µm to 7–10 µm with increasing the content of eutectic glass. The developed celsian ceramic has a set of enhanced physical and thermal properties: zero water absorption and open porosity, mechanical compressive strength (up to 157 MPa), refractory index is 1540–15800C. Celsian ceramic is characterized by a coefficient of linear thermal expansion of 3410–7 0C–1, which provides a sufficiently high thermal shock resistance of 700 0C. In terms of the level of relative dielectric permittivity (5.5) and dielectric losses (0.0005) at a frequency of 1010 Hz, the developed ceramic meets the requirements for ultra-high-frequency radiotransparent materials for aviation and rocket technology, which operate under conditions of high-speed high-temperature heating. [ABSTRACT FROM AUTHOR]

Modern communication systems call for high performance electromagnetic wave absorption materials capable of mitigating microwaves over a wide frequency band. The synergistic effect of structure and component regulation on the electromagnetic wave absorption capacity of materials is considered. In this paper, a new type of three-dimensional porous carbon matrix composite is reported utilizing a reasonable design of surface impedance matching. Specifically, a thin layer of densely arranged Fe-Cr oxide particles is deposited on the surface of porous carbon via thermal reduction to prepare the Fe-Cr-O@PC composites. The effect of Cr doping on the electromagnetic wave absorption performance of the composites and the underlying attenuation mechanism have been uncovered. Consequently, outstanding electromagnetic wave absorption performance has been achieved in the composite, primarily contributed by the enhanced dielectric loss upon Cr doping. Accordingly, an effective absorption bandwidth of 4.08 GHz is achieved at a thickness of 1.4 mm, with a minimum reflection loss value of −52.71 dB. This work not only provides inspiration for the development of novel absorbers with superior performance but also holds significant potential for further advancement and practical application. [ABSTRACT FROM AUTHOR]

The problems of electromagnetic wave (EMW) pollution in X and Ku bands (8–18 GHz) are becoming more and more serious. Therefore, it is urgent to design EMW absorbing materials with high-efficiency such as thin thickness, lightweight, wide bandwidth and strong EMW absorption. Inspired by the biomorph of sea cucumber, Nb2CTx MXene@Co nitrogen-doped carbon nanosheet arrays@carbon fiber aerogels (Nb2CTx@Co-NC@CFA, Nb2CTx = niobium carbide) were constructed by self-assembly, in-situ chemical deposition and subsequent pyrolysis. The carbon fiber aerogel, as the basic skeleton of sea cucumber, forms lightweight three-dimensional interconnected conductive network, enhances the dielectric loss and extends the multiple reflection and absorption paths of EMW. As the tentacles of sea cucumber surface, Nb2CTx MXene and Co nitrogen-doped carbon nanosheet arrays exist rich heterogeneous interfaces, which play an important role in improving EMW polarization loss and optimizing impedance matching. The minimum reflection loss (RLmin) of Nb2CTx@Co-NC@CFA reaches −54.7 dB at 9.84 GHz (2.36 mm) with a low filling ratio of 10 wt.% and the effective absorption bandwidth (EAB) of Nb2CTx@Co-NC@CFA reaches 2.96 GHz (8.48–11.44 GHz) with 2.36 mm and 5.2 GHz (12.8–18 GHz) with 1.6 mm, covering most of X and Ku bands by adjusting thickness. The radar cross section (RCS) value of Nb2CTx@Co-NC@CFA is 26.64 dB·m2, which is lower than that of the perfect electrical conductor (PEC), indicating that Nb2CTx@Co-NC@CFA can effectively decrease the probability of the target being detected by the radar detector. This work provides ideas for design and development of EMW absorbing materials with high-efficiency EMW absorption in X and Ku bands. [ABSTRACT FROM AUTHOR]

Facing the complex variable high-temperature environment, electromagnetic wave (EMW) absorbing materials maintaining high stability and satisfying absorbing properties is essential. This study focused on the synthesis and EMW absorbing performance evaluation of TiN/Fe2N/C composite materials, which were prepared using electrostatic spinning followed by a high-temperature nitridation process. The TiN/Fe2N/C fibers constructed a well-developed conductive network that generates considerable conduction loss. The heterogeneous interfaces between different components generated a significant level of interfacial polarization. Thanks to the synergistic effect of stable dielectric loss and optimized impedance matching, the TiN/Fe2N/C composite materials demonstrated excellent and stable absorption performance across a wide temperature range (293–453 K). Moreover, TiN/Fe2N/C-15 achieved a minimum reflection loss (RL) of −48.01 dB and an effective absorption bandwidth (EAB) of 3.64 GHz at 2.1 mm and 373 K. This work provides new insights into the development of high-efficiency and stabile EMW absorbing materials under complex variable high-temperature conditions. [ABSTRACT FROM AUTHOR]

Defects and defective technology are considered to be an efficient method for improving electromagnetic wave (EMW) absorption performance. In this study, W-type barium hexaferrite BaCo2Fe16O27 (BCFO) composites with Sm doping were synthesized by a simple ball milling and subsequent annealing process. The phase structure characteristics, magnetic properties, and microwave absorption performance of the BCFO composites were systematically investigated. Specifically, Sm-doped and annealed BCFO composites demonstrated outstanding microwave absorption characteristics because of the efficient interaction between ideal impedance matching and large dielectric loss, specifically, a minimum reflection loss (RL) value of −28.57 dB at 8.5 GHz with 3 mm thickness. Moreover, a broad effective absorption bandwidth reaches 11 GHz, covering the range of 7–18 GHz. It is believed that defects and vacancies induced by Sm doping or annealing in the Ar atmosphere may be an effective means for enhancing microwave absorption, and related mechanisms are discussed in detail. [ABSTRACT FROM AUTHOR]

Neodymium doped rubidium titanyl phosphate single crystal was grown from the high-temperature flux technique. To investigate the material stability in the radiation background, for the first-time neodymium doped rubidium titanyl phosphate single crystal was subjected to gamma ray irradiation. After the irradiation of the 2.6-kGy gamma-radiation, the material's optical and electrical properties were analyzed and the results have been compared to that of non irradiated Nd: RTP single crystal. A small absorption band was found in the visible region around 0.08 higher than the non -irradiated Nd: RTP single crystal and there is a small variations in the band gap energy, 3.61 eV for non -irradiated Nd: RTP single crystal and 3.54 eV for gamma irradiated Nd: RTP single crystal. The dielectric constant, dielectric loss, and AC conductivity was observed for non-irradiated and gamma irradiated Nd: RTP single crystals. The Gamma radiation irradiated Nd: RTP single crystal shows little higher value of dielectric constant, loss and conductivity around 0.07, 0.05 and 1.2 S/cm from the non irradiated sample respectively. From the ferroelectric studies there is an increase in polarization and coercive field were observed in the gamma-ray irradiated sample from that of non-irradiated Nd: RTP single crystal. This can be attributed to radiation-induced defects is local strains and movements of ions inside the crystal. Besides the Gamma irradiated sample shows fatigue free nature over the 5000 cyclic period. The gamma-ray induced a defect in material but not far away from application requirements and the radiation effect had been removed through the thermal annealing process. [ABSTRACT FROM AUTHOR]

(1-x)PVDF/(x)LFO-BTO composite films with weight percentages (x = 0, 0.05, 0.1 and 0.15) were prepared by solution casting method. Phase identification was carried out using the X-ray diffraction (XRD) technique revealing different phases (α, β & γ) of PVDF. FTIR results confirmed the presence of different vibrational modes and phases including PVDF phases. AFM and SEM were used to investigate the surface & morphological analysis, the results showed that the surface roughness increased with the concentration of LFO-BTO into PVDF films. From optical absorption spectra, the direct band gap and indirect band gap energies of the PVDF/LFO-BTO were evaluated by incorporating Tauc's relation. The composites experienced a reduction in band gap upon the addition of 0 - 15 wt% of LFO-BTO with an increasing trend in Urbach's energy. The dielectric investigations revealed elevated dielectric constant values across all composites at lower frequency ranges, attributed to interfacial polarization. Specifically, the dielectric constant of 15 % wt of LFO-BTO was found to be much higher (6 times more than the pristine PVDF). Additionally, the dielectric loss was suppressed with increasing filler concentration within the frequency range of 1 KHz to 1 MHz. Impedance spectroscopy analysis depicted a distinctive semi-circular pattern that was linked to the underlying conduction mechanism. The behaviour of ac-conductivity revealed the conduction process following the Nyquist plot. DTA-TGA analysis showed a notable improvement in thermal stability with increasing concentration in the PVDF matrix. [ABSTRACT FROM AUTHOR]

A solid-state synthesis method was employed to produce (Mg 1-x Mn x) 2 Ti 0.95 Ga 1/15 O 4 (x = 0.06,0.12,0.18, and 0.24), which is intended for use in mobile communications. This involved using a combination of Mg 2 Ti 0.95 Ga 1/15 O 4 and Mn 2 Ti 0.95 Ga 1/15 O 4 solid solutions. By substituting Mg2+ and Mn2+, the resulting material exhibited an improved Q × f value and achieved densification (ρ re = 97.62 %) at a lower sintering temperature compared to the sintering temperature required for Mg 2 TiO 4 , which is 1450 °C. After sintering at 1350 °C for 4 h, (Mg 0.94 Mn 0.06) 2 Ti 0.95 Ga 1/15 O 4 ceramic showed optimal dielectric properties (ε r = 14.59, Q × f = 263,953 GHz, τ f = −61.86 ppm/°C). To delve deeper into the inherent mechanisms of the ceramic's microwave dielectric properties, a thorough analysis was conducted based on the P–V-L theory. Additionally, XRD analysis revealed a minor secondary phase (Mg 1-x Mn x Ti 0.95 Ga 1/15 O 3) that deteriorated loss characteristics. SEM provided a comprehensive view of the grains' morphologies, giving crucial insights into the microstructure, while Raman spectroscopy explored into the intricate influence of lattice vibrations on the microwave dielectric properties of the ceramics. [ABSTRACT FROM AUTHOR]

Bi 0.5 Na 0.5 TiO 3 -based ferroelectric materials with strong ferroelectricity and high Curie temperature have great application prospects in modern microdevices. In this paper, 0.92BNT-0.08BT ceramic coating was prepared by supersonic plasma spraying. The phase, microstructure, electrical properties and domain response of 0.92BNT-0.08BT ceramic coating were analyzed. The findings demonstrate that the 0.92BNT-0.08BT ceramic coating is without obvious structural defects and has a completely structure with good interface bonding. 0.92BNT-0.08BT ceramic coating has good electrical properties, the dielectric constant is 417, the dielectric loss is 0.3, and the remnant polarization is 16.6 μC/cm2. The piezoelectric force microscopy (PFM) results show that the 0.92BNT-0.08BT ceramic coating generally exhibits irregular and inhomogeneous striped nanodomains, with significant changes in amplitude and phase response under different electric fields. The results using switching spectroscopy-piezoresponse force microscopy (SS-PFM) show that the local piezoelectric coefficient (PR max) of the 0.92BNT-0.08BT ceramic coating reaches 754.3 p.m./V at a voltage of 20 V, and the ferroelectric domains exhibit a clear switching behavior. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites are promising for various industrial and scientific applications due to their flexibility, diverse functionalities, and unique properties. In this study, zinc oxide nanorods (ZnO NRs) were incorporated into a blend of polymers (Hydroxypropyl methylcellulose - HPMC and Polyvinyl pyrrolidone - PVP) using a solution-casting technique, with concentrations varying from 2 % to 8 % by weight. Transmission electron microscopy (TEM) revealed that the ZnO NRs had an average diameter of 140 nm and a length of 3.22 μm. X-ray diffraction (XRD) analysis showed reduced crystallinity in the samples as the ZnO NR content increased. Fourier-transform infrared spectroscopy (FTIR) indicated changes in vibrational peaks due to interactions between functional groups in the blend and the nanorods. The addition of ZnO NRs significantly influenced the optical bandgap energies and UV/visible light absorption spectra of the samples. The bandgap of the nanocomposites significantly decreased upon ZnO NR incorporation, with direct and indirect bandgaps ranging from 5.19 to 4.70 eV and 4.74–3.66 eV, respectively. Electrical conductivity and dielectric characteristics were assessed across frequencies ranging from 0.1 to 10 MHz, revealing increasing AC conductivity, dielectric permittivity, and dielectric loss with higher ZnO NR content. Notably, at 10 Hz, the electrical conductivity increased from 3.5 × 10⁻12 S/m to 3.62 × 10⁻10 S/m upon loading with ZnO NR. The combination of adjustable optical bandgaps, frequency-dependent AC conductivity, and a wide range of tunable permittivity highlights the potential of these HPMC/PVP-ZnO NR nanocomposites for developing flexible optoelectronic and energy storage devices. [ABSTRACT FROM AUTHOR]

As communication technology continues to evolve, 5G technology is becoming more mature, and 6G technology is steadily advancing. Microwave equipment is moving toward high frequency, miniaturization, low loss and high temperature stability, and microwave dielectric ceramics have been deeply applied in this field. To elevate the Q × f value of CoNb2O6 system, Ta5+ was introduced into CoNb2O6, and CoNb2‐xTaxO6 (0.0 ≤ x ≤ 0.8) ceramics were prepared by the traditional solid‐phase method. By X‐ray diffraction, it was observed that at x = 0.8, in addition to a single niobium ferrite phase, information of tantalate phase also appeared. Raman spectral detection and group theory analysis indicate that Ag(2) and Ag(3) modes are the dominant Raman vibrations at ≈873 cm−1. Furthermore, the polarization rate affects the εr value, and the bond energy of Nb/Ta‐O and the recovery force characterized by the average deformation of the [Nb/TaO6] octahedron are the key elements influencing the temperature coefficient of the resonance frequency (τf). The internal strain, ordered induced size, and chemical bonding valence of ionic valence states are the key factors that can increase the Q × f value. Moreover, the introduction of ions with lower electronegativity leads to an enhanced electronic compensation of oxygen vacancies, which also reduces the dielectric loss. This paper enriches the theory related to low dielectric loss and shows that CoNb1.8Ta0.2O6 (εr = 21.4832, Q × f = 100723 GHz, τf = ‐61.38 ppm/°C) ceramics with superior microwave dielectric properties are expected to be used in wireless communication devices. [ABSTRACT FROM AUTHOR]

For energy storage applications, attaining high dielectric permittivity as well as low loss factor is the foremost target. This could be accomplished via filling polymer matrices with inorganic filler which is characterized by relatively high dielectric permittivity. In the present study, polyvinyl butyral (PVB) was used as a matrix material for preparing nanocomposite films filled with different weight fractions (2, 5, 10, and 15%) of barium titanate (BaTiO3) using the casting approach. The results show that BaTiO3 (BT) is well incorporated inside the PVB matrix. Although the dielectric permittivity has been decreased from 3.61 to 2.41 at 1 kHz upon filling the PVB matrix with 5 wt. % of BT, the PVB-BT-NPs-5 nanocomposite film shows the lowest loss factor ~ 0.0049, nearly half that for PVB, 0.0092, which implies the increased film ability to keep its stored energy. The PVB-BT-NPs-5 has been irradiated with gamma radiation to investigate its impact on the structure beside its dielectric and thermal properties. The crystallite size of BT has been decreased from 20.64 to 17.77 nm as PVB-BT-NPs-5 nanocomposite film has been irradiated at a dose of 0.5 kGy. The dielectric permittivity has been decreased from 2.41 to 2.37 at 1 kHz, whereas an increase from 0.0049 to 0.0073 in the loss factor is observed. Furthermore, the thermal stability has been decreased due to the deformation induced by gamma rays inside the nanocomposite films. Therefore, these nanocomposite films could be better exploited in energy storage applications in its un-irradiated form. [ABSTRACT FROM AUTHOR]

Bio‐based flexible dielectric substrates have gained tremendous attention for their potential to reduce environmental risks from nonbiodegradable electronic waste. The present study demonstrates the fabrication of facile, nontoxic, and biodegradable chitosan‐based flexible dielectric substrate using graphene nanoplatelet (GNP) as a nanofiller. The detailed impact of different concentrations of GNP (1, 2, and 3 wt%) into the chitosan (CS) matrix was studied on physicochemical, morphological, mechanical, electrical, and thermal properties. The fabricated CS/GNP composites showed improved mechanical strength, thermal stability, and electrical properties compared with unmodified CS film. The composites exhibited excellent thermal stability (200°C) with a promising biodegradation rate (within 6 days). The mechanical strength of the unmodified CS film was increased unequivocally with 2 wt% GNP loading with tensile strength of 23.56 Mpa. Furthermore, the current–voltage (I–V) characteristic curves for CS/GNP (2%) and CS/GNP (3%) showed similar current conduction and ohmic behavior in flat, bending, and flat‐after‐bending modes. The dielectric measurements revealed that the CS/GNP composite with 2 wt% filler exhibited optimal performance having permittivity (έ) of 32.71 (at 102 Hz) with low dielectric loss of 0.04 (at 106 Hz). These results suggest that the dielectric films offer strong prospects as an eco‐friendly alternative for various applications. Highlights: Biodegradable chitosan‐based flexible dielectric films were prepared.Films were made using a simple solvent casting method with 1–3 wt% GNP filler.Optimum physicochemical and electrical properties were seen at 2 wt% GNP.CS/GNP (2%) film exhibited ohmic behavior in both flat and bending modes.Excellent dielectric properties were achieved at 2 wt% GNP filler. [ABSTRACT FROM AUTHOR]

Present studies investigate the dielectric properties (dielectric constant and dielectric loss factor) of three low moisture flours (barley, chickpea and wheat) in the moisture content range 2%–10% (w. b.) and temperatures 10°C–60°C at 2.45 and 5.8 GHz. Measurements were taken using cavity perturbation method in conjunctions with Vector Network Analyzer. Results show that dielectric constant and loss factor increased with temperature as well as moisture content both at 2.45 and 5.8 GHz but decreased with increase in frequency. Change in mass of all flours during heating does not affect dielectric properties at both frequencies. A second order regression equation is generated to predict dielectric properties at both frequencies for entire temperature and moisture. Penetration depths of all flours decreased with increase in moisture content and temperature at 2.45 and 5.8 GHz. These studies provide valuable insights to heating protocol of flours in view of recent flours-related disease outbreaks. [ABSTRACT FROM AUTHOR]

Bi0.5Na0.5TiO3 (BNT) emerges as a promising ferroelectric and piezoelectric lead-free candidate to substitute the contaminant Pb[TixZr1−x]O3 (PZT). However, to obtain optimal ferroelectric and piezoelectric properties, BNT must be sintered at high temperatures. In this work, the reduction of sintering temperature by using iron added to BNT is demonstrated, without significant detriment to the dielectric properties. BNT-xFe with iron from x = 0 to 0.1 mol (∆x = 0.025) were synthesized using high-energy ball milling followed by sintering at 900 °C. XRD analysis confirmed the presence of rhombohedral BNT together with a new phase of NaFeTiO4 (NFT), which was also corroborated using optical and electronic microscopy. The relative permittivity, in the range of 400 to 500 across all the frequencies, demonstrated the stabilization effect of the iron in BNT. Additionally, the presence of iron elevates the transition from ferroelectric to paraelectric structure, increasing it from 330 °C in the iron-free sample to 370 °C in the sample with the maximum iron concentration (0.1 mol). The dielectric losses maintain constant values lower than 0.1. In this case, low dielectric loss values are ideal for ferroelectric and piezoelectric materials, as they ensure minimal energy dissipation. Likewise, the electrical conductivity maintains a semiconductor behavior across a range of 50 Hz to 1 × 106 Hz, indicating the potential of these materials for applications at different frequencies. Additionally, the piezoelectric constant (d33) values decrease slightly when low concentrations of iron are added, maintaining values between 30 and 48 pC/N for BNT-0.025Fe and BNT-0.05Fe, respectively. [ABSTRACT FROM AUTHOR]

Bismuth layer‐structured ferroelectrics (BLSF) show great potential as piezoelectric materials for high‐temperature applications. In this study, c‐axis/[001]‐textured CaBi4Ti4O15 (CBT) ceramic was synthesized through templated grain growth (TGG) method. A high Lotgering factor (f) of 96% was achieved in textured CBT ceramic using 20 wt% CBT homogeneous template. The piezoelectric coefficient d33 has significantly increased from 7.8 pC/N for random ceramic to 24.3 pC/N for textured ceramic (poled perpendicular to the c‐axis/[001] texture direction), representing an impressive 300% enhancement while maintaining an ultra‐high Curie temperature (TC) of 788°C. In addition, a low dielectric loss (tanδ = 0.4%) and relatively high resistivity (ρ = 1.1 × 1012 Ω·cm) were achieved simultaneously at room temperature. The significant enhancement of d33 in textured CBT ceramic origins from its strong piezoelectric anisotropy. The large d33,T⊥ is due to the nature of polarization switching in CBT (the spontaneous polarization PS of CBT is along a‐axis direction, and the switching of PS is restricted within the a–b plane). Furthermore, the variation of d33,T⊥ remained below 10% across the temperature range of 25–700°C, highlighting the excellent thermal stability of the textured CBT ceramics. These findings suggest that textured CBT ceramic is a promising piezoelectric material for high‐temperature sensor applications. [ABSTRACT FROM AUTHOR]