Search

With the waste of resources caused by human activities, it has gradually become an increasingly prominent social problem. The development of self-healing polymers in the field of insulation has attracted widespread attention. Develop polymer matrices with efficient healing efficiency and sound insulation properties to achieve green and sustainable resource conservation. In addition, improving the dielectric properties of intrinsic self-healing matrices has been a hot topic. In this work, we developed a new PEI matrix-modified self-healing polymer substrate that provides a breakdown field strength of 240 kV/mm and self-healing properties at room temperature, this has significantly improved the dielectric properties over other previously reported self-healing polymers. In addition to the abovementioned performance, we found significant differences in thermodynamic behavior in the synthesized end-modified polymers. By dielectric characterization (LCR), the breakdown composite can be left at room temperature for 60 min, and the material can recover 80 % of the initial properties without external intervention(This is demonstrated by the fact that its DC conductivity at 60 min of autonomous healing was significantly changed from that of the freshly electrically pierced DC conductivity and remained around 5.38 × 10−11 S/cm for a longer period of time thereafter). The microscopic morphology of the modified PEI matrix was observed by scanning electron microscopy (SEM) and EDS surface elemental analysis, which further supports the existence of metal coordination structures. These findings can further deepen the thinking of self-healing dielectric composites. The work inspired by this may break the limits and take self-healing composite dielectric materials to a new height. [ABSTRACT FROM AUTHOR]

High entropy oxides with interesting physical properties can be obtained by the design of A-site cations. Herein, a series of medium entropy and high entropy perovskite ceramics (Ba 0.25 Sr 0.25 Ca 0.25 Bi 0.25)TiO 3 , (Ba 0.2 Sr 0.2 Ca 0.2 Bi 0.2 La 0.2)TiO 3 , (Ba 0.2 Sr 0.2 Ca 0.2 Bi 0.2 Na 0.2)TiO 3 and (Ba 0.2 Sr 0.2 Ca 0.2 La 0.2 Na 0.2)TiO 3 were synthesized by the solid-state method, which selected various valence elements to achieve a single-phase structure and increase the lattice distortion. The microstructure indicated that the high-entropy ceramics exhibited the same macroscopic single perovskite while the local configuration is different. Mesoscopic results show that high entropy can adjust the polarization and relaxation of ferroelectrics, so as to optimize the energy storage performance. Meanwhile, the results manifest that grain boundaries, oxygen defects and relaxation can be changed by entropy configuration. Our work proves that the properties of high entropy ferroelectric materials can be regulated by different valence states of the elements in high entropy and explores the relevant mechanism, which provides a possible opportunity for the design and application of high-entropy dielectric materials with excellent properties. [ABSTRACT FROM AUTHOR]

Extensive studies on TiO 2 -based colossal permittivity (CP, dielectric constant ε' >103) materials have focused on the cation doping of metal elements; however, little attention has been paid to nonmetallic dopants. Compared to metallic elements, nonmetallic atoms with small radii and high activities, such as H, C, B, and N, can be used as anion-doping elements. Their incorporation into the TiO 2 lattice includes interstitial and substitutional doping, which can influence the bandgap of TiO 2 and its electron transport performance differently, thereby exhibiting considerable potential in TiO 2 -based applications. In this study, different N-containing compounds (BN and NH 4 Cl) were doped into rutile TiO 2 , while homogeneous ceramics of single-phase rutile TiO 2 were prepared via solid-state sintering. The effects of co-doping N, Cl, and N, B on the dielectric properties of rutile TiO 2 ceramics were investigated. While N and Cl doping showed no considerable effect on the dielectric properties of rutile TiO 2 ceramics, the co-doping of N and B doping in rutile TiO 2 considerably increased the dielectric constant to >104 with suppressed tan δ in a wide frequency range from 1 kHz to 10 MHz. These ceramics exhibited excellent frequency stability (up to 100 MHz) and temperature stability (153–513 K), which outperforms most reported transition metal co-doped TiO 2 ceramics, thereby highlighting the untapped potential of the non-metallic dopants in enhancing dielectric materials. [ABSTRACT FROM AUTHOR]

Glasses formed from transition metal oxides have shown tailorable electrical and optical properties depending on the valence state and individual element. Vanadate glasses have received specific attention for their high conductivities as compared to most glass families. In this study, the frequency‐dependent capacitance and direct current (dc) conductivity properties of alkaline earth vanadate glasses were investigated. Glasses in the xSrO–(100 − x)V2O5 and xBaO–(100 − x)V2O5 systems, where x = 30, 40, and 50 in mol%, were prepared via melt‐quench synthesis. Capacitance measurements were used to calculate dielectric constants, dielectric loss, and alternating current (ac) conductivity for each sample. Dielectric constants varied between 10–13 and 14–16 for SrO–V2O5 and BaO–V2O5 glasses, respectively, at 1 MHz. Current measurements were made as a function of temperature and voltage for each glass sample. A strong dependence on vanadate content was noted where temperature had a less strong effect. Activation energies were calculated to describe electrical transport mechanisms. All samples showed activation energies governed by electron hopping mechanisms. Such vanadate glasses have properties suitable for applications as cathode materials for batteries, solid state electrolytes, and conductive glass paste with potential for electro‐optic effects involving nonlinear processes. [ABSTRACT FROM AUTHOR]

Polymer-based dielectric composites show great potential prospects for applications in energy storage because of the specialty of simultaneously possessing the advantages of fillers and polymer matrices. However, polymer-based composites still have some urgent issues that need to be solved, such as lower breakdown field strength (Eb) than polymers, dielectric mismatch, and the poor interface between the matrix and the filler. Hence, this review provides a systematic summary of recent research advances in improving the energy storage properties of polymer-based composites from several aspects, mainly including polymer matrix types, optimization of filler shapes, surface modification of fillers, and design of multi-layer composite structures. Finally, some existing challenges and future perspectives are outlined and discussed to facilitate the further development of polymer-based composites in the energy storage field. We believe this review will help researchers better understand the current development status of polymer-based composites in the energy storage field, and push it forward to a new research stage. [ABSTRACT FROM AUTHOR]

Ferrite compounds have gained scientific attention for their multifunctional attributes. This investigation explores the structural, optical, dielectric and conductivity properties of polycrystalline γ-Fe 2 WO 6 synthesized by the solid state route. The X-ray diffraction confirmed the orthorhombic structure and single-phase formation, while the electron microscopy showed uniform distribution of dense micrometer-sized grains in γ-Fe 2 WO 6. The FTIR spectroscopy analysis validated the presence of active stretching and bending modes, signifying oxygen anion vibration at both Fe and W sites. The simultaneous presence of Fe2+ and Fe3+ ions in the matrix, as confirmed by X-ray photoelectron spectroscopy (XPS), results in an augmented optical energy band gap and contributes to dielectric permittivity due to the charge carrier hopping mechanism between the trap sites. The compound manifests semiconductor attributes, evident in its indirect optical band gap measuring 1.7 eV. It is observed that the compound has effectively degraded the Methylene Blue (MB) under the visible light within 40 min with a degradation efficiency up to 63 %. The material's electrical conductivity, follows the Jonscher's power law, signifies its semiconductor nature and adheres to the Small Polaron tunneling model for charge conduction between neighboring sites. The impedance (Z′) curves exhibit dielectric relaxation (≤ 10 kHz) with a similar activation energy to the dc conductivity study. The activation energy, determined from both the impedance and conductivity analyses, indicates a connection with the migration of oxygen vacancies within the material. Our observation reveals the presence of oxygen vacancies, which possibly act as in-gap electron traps, enhancing the correlated optical and ac conductivity properties, making it an appealing material for diverse multifunctional applications. [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]

Due to increasing global energy demands and environmental concerns, the search for alternative and environmentally friendly energy sources is of paramount importance. Solid oxide fuel cells (SOFCs) have emerged as a promising solution thanks to their high efficiency and minimal environmental impact. In this regard, perovskite oxides, with their unique properties, have attracted significant attention. This study investigates the dielectric dispersion, electrical features, scaling behavior, and optical defects of Ca 0.67 La 0.22 Ti 0.85 Cr 0.15 O 3 with x = 0.15, CLT 0.85 Cr 0.15. The presence of a vacancy in the A-site is denoted by the square in the formula. Relaxation phenomena were analysed using dielectric and modulus formalism, while the conductivity mechanism was explored through electrical conductivity measurements. The optical defects of CLT 0.85 Cr 0.15 were analysed using electron paramagnetic resonance (EPR) spectroscopy. The findings revealed the formation of Cr3+–VO center defects. These defects serve as sources of in-gap electron traps, thereby enhancing the optical properties of CLT 0.85 Cr 0.15 , making it as a compelling material for various optical applications. The power density increased with temperature, reaching 0.73 W/cm2 at 850 °C, suggesting that CLT 0.85 Cr 0.15 could be a promising electrolyte for IT-SOFCs. The peak in power density correlated with temperature due to thermal effects on ion motion. However, the open circuit voltage decreased with temperature increase, due to increased oxygen vacancies and electron/hole conduction in CLT 0.85 Cr 0.15. The findings suggest that perovskite materials could revolutionize SOFCs technology, paving the way for more efficient and environmentally friendly energy solutions. [ABSTRACT FROM AUTHOR]

In this paper, we describe the synthesis of cerium molybdate (Ce 2 (MoO 4) 3) and different compositions of Bi-doped cerium molybdate (Ce 2-x Bi x (MoO 4) 3) where x = 0.01, 0.03, 0.05, 0.07, and 0.09, through simple co-precipitation method. The synthesized materials were optically, structurally, and morphologically characterized by various sophisticated techniques, including UV–visible, FTIR, Raman, PXRD, BET, and SEM-EDX. Upon addition of bismuth, the optical band gaps are reduced from 3.35 eV (Ce 2 (MoO 4) 3) to 2.83 eV Ce 1.93 Bi 0.07 (MoO 4) 3. The charge storage potential and AC conductivity of the synthesized materials were investigated through dielectric studies where the dielectric constant increased by increasing dopant concentration up to 7 %. At 20 Hz, Ce 1.93 Bi 0.07 (MoO 4) 3 showed a significantly greater dielectric constant (3.597 × 106) compared to undoped Ce 2 (MoO 4) 3 (3.262 × 105). Similarly, the AC conductivity of Ce 1.93 Bi 0.07 (MoO 4) 3 increased up to 4.758 S m−1 compared to the undoped Ce 2 (MoO 4) 3 (2.270 S m−1) at 20 MHz. The photocatalytic efficiency was investigated against diclofenac potassium, which also considerably improved by increasing bismuth content. The maximum photodegradation efficiency of 87.9 % was observed for Ce 1.93 Bi 0.07 (MoO 4) 3 in 180 min under UV light irradiation at optimized conditions (pH = 4, catalyst dosage = 20 mg, and initial concentration of drug = 5 mg L−1). The photocatalytic reaction followed pseudo-first-order kinetics with a rate constant of 0.0108 min−1 with stability up to five successive runs of photocatalytic activity indicating its good recyclability. These findings suggest that Bi-doped cerium molybdate could be used as a promising material for photocatalysis and energy storage devices. [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 work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors. [ABSTRACT FROM AUTHOR]

Dielectrics are non‐conducting substances that are primarily utilized to hold electric charges. These materials are widely employed in the field of chemical mechanical, civil and structural engineering, because of their inherent insulating properties. Besides these domains, dielectric materials are also used in electrical and electronic applications. Dielectric materials have shown an ever‐increasing potential in recent years in the fabrication of antennas, sensors, and optical devices that are extensively utilized for on‐body, environmental, robotics, and biomedical applications. With inherent electrostatic shielding, insulation, and dielectric relaxations, these materials are used in intelligent electronic devices used for biomedical applications, smart devices, vehicles, and future IoT applications. Numerous applications necessitate multiple kinds of dielectric, classified based on their polarization, flexibility, thickness, dielectric constant, and specific application. In this extensive research review, the characteristics and various aspects of dielectric materials are discussed, followed by a thorough and detailed review of flexible dielectrics and their usage in flexible electronics. Additionally, the practicality and applications of these materials which come from a variety of publications in the literature are also discussed. Moreover, in‐depth study of dieletrics in sensors and RF applications are performed. [ABSTRACT FROM AUTHOR]

Ca and Cs doped barium titanate lead-free ceramic with the formula Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 has been prepared by the solid-state reaction method. X-ray diffraction (XRD) confirms the crystallization of the sample in a tetragonal structure with a P 4 mm space group. The phase purity and grain morphology were evaluated using X-ray diffraction and scanning electron microscopy (SEM). The material exhibits a primary phase of Ba0.75Ca0.2Cs0.05TiO3 with a minor secondary phase of BaO 2 , and the average grain size is determined to be 1.66 μm. Using non-destructive complex impedance spectroscopy (CIS), we extensively studied the electrical behavior, including complex impedance (Z*), complex modulus (M*), electrical conductivity, and relaxation mechanisms, of Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 over a wide temperature (85 K–290 K) and frequency range. The ac conductivity analysis reveals that the dominant conduction mechanism is the non-overlapping small polaron tunneling (NSPT) model. The impedance analysis indicates a single semi-circle in the real and imaginary parts, suggesting a single relaxation mechanism. Additionally, the activation energy was calculated to be approximately 0.0489 eV. These findings contribute to the understanding of the structural and electrical properties of Ba 0.75 Ca 0.2 Cs 0.05 TiO 3 , highlighting its potential applications in electronic devices such as capacitors, thermistors, and ferroelectric random access memories (FRAMs). [ABSTRACT FROM AUTHOR]

In the present work the atomic, electronic and optical properties of two-dimensional graphene, borophene, and boron carbide heterojunction bilayer systems (Graphene–BC3, Graphene–Borophene and Graphene–B4C3) as well as their constituent monolayers are investigated on the basis of first-principles calculations using the HSE06 hybrid functional. Our calculations show that while borophene is metallic, both monolayer BC3 and B4C3 are indirect semiconductors, with band-gaps of 1.822 eV and 2.381 eV as obtained using HSE06. The Graphene–BC3 and Graphene–B4C3 bilayer heterojunction systems maintain the Dirac point-like character of graphene at the K-point with the opening of a very small gap (20–50 meV) and are essentially semi-metals, while Graphene–Borophene is metallic. All bilayer heterostructure systems possess absorbance in the visible region where the resonance frequency and resonance absorption peak intensity vary between structures. Remarkably, all heterojunctions support plasmons within the range 16.5–18.5 eV, while Graphene–B4C3 and Graphene–Borophene exhibit a π -type plasmon within the region 4–6 eV, with the latter possessing an additional plasmon at the lower energy of 1.5–3 eV. The dielectric tensor for Graphene–B4C3 exhibits complex off-diagonal elements due to the lower P3 space group symmetry indicating it has anisotropic dielectric properties and could exhibit optically active (chiral) effects. Our study shows that the two-dimensional heterostructures have desirable optical properties broadening the potential applications of the constituent monolayers. [ABSTRACT FROM AUTHOR]

The structural, microstructural, dielectric, optical, ferroelectric, and magnetic properties of cobalt doped barium calcium titanate (BCT) (Ba 0.80 Ca 0.20 Ti 1-x Co x O 3 with x = 0.000, 0.005, 0.010, 0.015, and 0.020) ceramics have been reported in this paper. The ceramic samples were prepared by the conventional solid-state reaction method. For all of the prepared samples, the tetragonal structure with the space group P 4 mm has been confirmed using the refinement method through Rietveld refinement of X-ray diffraction patterns. Field Emission Scanning Electron Microscopy (FESEM) micrographs revealed that the average particle size exists in micrometre range (0.3–0.8) μm. Optical studies revealed a gradual decrease in the energy bandgap from 3.31 eV to 2.71 eV with increasing doping concentration. A decreasing trend was observed in the dielectric characteristics of the material with changing frequencies at room temperature. Ferroelectric (P-E loops) analysis displayed an increase in both remnant polarization and maximum polarization of the ceramic with the increasing applied electric field. The highest value for the energy storage efficiency (η) was calculated to be 20.51 %. Magnetic analysis conducted at room temperature revealed the enhancement in ferromagnetism with the increase in doping concentration. [ABSTRACT FROM AUTHOR]

The integrable substrate for THz modulation directly influences both the quality of films and THz absorption. Currently, the available THz substrate candidate library is still not clear. Here, we have carried out a systematic investigation of commonly used commercial substrates, including Si, quartz SiO2, MgO, Al2O3, GdScO3 and TbScO3 in the range of 0.4–1.6 THz. It is found that low resistance Si, TSO and GSO are certainly not appropriate for THz light modulation due to their relatively higher absorption and dielectric constant, while the rest show better THz transmittance, low refractive index and loss. However, the dielectric constant and refractive index of high resistance Si are generally two times larger than quartz SiO2, Al2O3 and MgO. Compared with Al2O3 and MgO, quartz SiO2 shows at least 50% lower dielectric constant, refractive index and absorption, making it the best candidate. Our research is believed to build the rich substrate candidate library for THz range light modulation. [ABSTRACT FROM AUTHOR]

The effect of boron doping on dielectric properties was examined using β-SrTa2O6:xEu3+ (x = 1.5 mol%, 3 mol%, 5 mol%, 10 mol%), β-SrTa2O6:xEu3+, yB3+ (x = 1.5 mol%, 3 mol%, 5 mol%, 10 mol%, y = 10 mol%) and BaTa2O6:xEu3+, yB3+ (x = 10 mol%, y = 0 mol%, 5 mol%, 15 mol%, 30 mol%, 50 mol%, 70 mol%, 100 mol%) tungsten bronze ceramics produced by the solid-state reaction method. X-ray diffraction (XRD) results of all the β-SrTa2O6 and BaTa2O6 samples showed that they retained a single-phase structure. In scanning electron microscopy (SEM) examinations, the presence of boron promoted grain growth and agglomeration in the β-SrTa2O6 grains, while the increased boron concentration led to grain elongation in addition to grain growth in the BaTa2O6 grains. The dielectric results for the β-SrTa2O6:xEu3+ and β-SrTa2O6:xEu3+, yB3+ series showed that increased Eu3+ caused a decrease in the dielectric constant (ε′) and dielectric loss (tan δ), whereas the increasing B3+ presence for the BaTa2O6:xEu3+, yB3+ series led to an increase in the dielectric constant and a decrease in dielectric loss. The increase in tetragonality for BaTa2O6:xEu3+, yB3+ ceramics was correlated with a higher ferroelectric Curie temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] The poor stability and slow lithium ion (Li+) transfer kinetics of solid electrolyte interphase (SEI) pose significant challenges to lithium (Li) metal batteries. Although various SEI-related strategies have been developed, the Li+ transport properties and uniform Li deposition still require substantial improvement for fast-charging applications. Herein, we introduce a dielectric, single-ion-conductive artificial SEI (DS-SEI) composed of lithiated Nafion and BaTiO 3 (BTO) nanoceramics to address these issues. The lithiated Nafion stabilizes the Li anode with its elastic F-rich components and facilitates fast, single Li+ conduction through its anion-anchored structure. The high-dielectric BTO dynamically homogenizes the electric field (E-field) to promote uniform Li deposition, synergistically enhancing intrinsic single Li+ conductivity and Li+ desolvation/diffusion kinetics, thereby enabling fast charging of the Li anode. Consequently, the DS-SEI protected Li anode can cycle over 6800 h in a Li||Li cell at 10 mA cm−2/5 mAh cm−2, over 400 cycles in a 2.75 mAh cm−2 Li||LiFePO 4 cell at 1C, with 83.0 % capacity retention at 6C (16.5 mA cm−2), and maintain stable cycling in a 5.62 mAh cm−2 Li||Li 6 PS 5 Cl|| LiNi 0.8 Co 0.1 Mn 0.1 O 2 all solid-state cell. Our findings provide insights into the interfacial regulation of Li anode, paving the way for fast-charging Li metal batteries. [ABSTRACT FROM AUTHOR]

Abstract The non-conventional manufacturing technologies are notorious when it comes to productivity and processing time in production-related industries. However, the aerospace and other high-end sectors enjoy another quality matrix of these processes and compromise on the processing time. For instance, the machinability of hard-to-cut materials such as Ti6Al4V aerospace alloy for micro-impressions is challenging and commonly carried out through non-conventional processes. Among these processes, the electric discharge machining (EDM) is famous for machining Ti6Al4V. In the current study, the EDM process is enhanced through modified dielectrics such as kerosene with non-ionic liquids (span 20, 60, and 80) and cryogenically treated tool electrodes (aluminum and graphite), and is compared to the conventional kerosene-based process. A three-phase experimental campaign is deployed to explore parametric effects including modified dielectric conditions (non-ionic liquid type and concentration), tool material, and machine parameter pulse ON:OFF time. A total of 60 experiments (54 modified dielectrics and 6 as baseline) were performed to explore process physics. The statistical analyses show that the unmodified process (kerosene dielectric-based) results in the least favorable results 0.58 mm3/min against cryo-graphite and 1.2 mm3/min against cryo-aluminum electrodes. However, the modified dielectrics outperform and improve process dynamics by altering dielectric conditions through hydrophilic-lipophilic balance. Surface morphological analysis shows significantly shallow craters on the machined surface showing evidence of effective flushing through a modified dielectric (S-20) as compared to a kerosene-based dielectric. A thorough microscopical, statistical, and scanning electron-based analysis is carried out to explain the process and correlate significant improvements.

The multiferroics with remarkable magnetoelectric (ME) coupling and technological application have drawn significant attention. Here, we report a chemical doping tunable effect on the magnetic, ferroelectric, and dielectric properties in type-II multiferroic Gd 2 BaCuO 5. The magnetic measurement results show that a long-range antiferromagnetic ordering forms at the Néel temperature (T N1) of ∼12.1 K, and a second magnetization anomaly occurs at a lock-in transition temperature (T N2) of ∼6.4 K. Sharp peaks in the pyroelectric and dielectric curves are observed at the magnetic transition temperatures, indicating intrinsic coupling between magnetic and ferroelectric orderings. The doping of Zn2+ results in a gradual enhancement of magnetization due to the increase of uncompensated spins, and large magnetodielectric (MD) coupling parameter up to ∼7.65 % is obtained in Gd 2 BaCu 0.7 Zn 0.3 O 5 because of strong spin-phonon coupling. The ferroelectric property is weakened in Zn2+ doped samples, suggesting the critical role of the 4 f -3 d magnetic interactions in determining the ME coupling effect. Moreover, an effective manipulation of electric field on magnetization is observed in Gd 2 BaCuO 5. This work helps understand the importance of 4 f -3 d magnetic interactions in inducing ferroelectricity and explore the ME and MD coupling effects with multiple magnetic orderings. [ABSTRACT FROM AUTHOR]

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na 0.5 Bi 0.5 TiO 3) and Co–Ti substituted Barium Hexaferrite (BaFe 12-2x Co x Ti x O 19 ; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63 / mmc hexagonal phases corresponding to Na 0.5 Bi 0.5 TiO 3 and BaFe 12-2x Co x Ti x O 19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x ≠ 0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future. [ABSTRACT FROM AUTHOR]

Forsterite was synthesized with MgCO 3 and SiO 2 powders using a solid-state method at 1200–1300°C. The ceramic specimen with the highest forsterite phase content was sintered with the ZrO 2 sintering aid at mass fractions of 0.5, 1.0, and 1.5 wt% at 1400°C for 4 h. The dielectric constant and loss tangent were also measured via the waveguide method at 8–12 GHz. The formation of enstatite and cristobalite was minimized through precise synthesis temperature control. Phase measurement by the Rietveld method showed that specimen F28 contained more than 99.8% forsterite. It was found that ZrO 2 reduced the pore volume percent and increased the density even at low mass fractions. A liquid phase on the grain boundaries was demonstrated. The solid ceramic specimen F28-15Z showed a dielectric constant of 6.5 and high quality factor of 189000. [ABSTRACT FROM AUTHOR]

In this study, lead-free Ba 0.85 Ca 0.15 Ti 0.95 (Nb 0.5 Yb 0.5) 0.05 O 3 (BC15TYN5) ceramic has been successfully obtained through the conventional solid-state reaction. It has been found the multifunctionality of the BC15TYN5 ceramic. It exhibits ferroelectric properties, with a significant remanent polarization value of about P r = 9.36 μC/cm2, and a recoverable energy storage density value of about W rec = 42.21 mJ/cm3. Additionally, it displays a dielectric permittivity of about ε ′ r = 7230 around T C = 80 °C, and an electro-caloric strength value of about ξ = 0.12 K mm/kV. It's worth noting that these values surpass those typically found in BaTiO 3 ceramics elaborated with similar experimental conditions. Electrical study (impedance, modulus, and conductivity characteristics) is essential for characterizing the BC15TYN5 material, determining its suitability for various technological applications, and optimizing manufacturing processes. The Cole-Cole plots exhibited two relaxations associated with the contribution of the grains and grain boundaries. The relaxation times for both grains and grain boundaries showed temperature-dependent variation following Arrhenius relation. The measured AC conductivity was evaluated by applying the Jonsher power law. Based on the thermal evolution of the exponent S , it was confirmed that the conduction mechanism follows the Correlated Barrier Hopping (CBH) model. These properties make BC15TYN5 ceramic suitable for applications such as dielectric capacitors, ferroelectric random-access memories, electrical energy storage units, and electro-caloric refrigeration systems. [ABSTRACT FROM AUTHOR]

Utilizing a high‐entropy strategy, we propose a novel approach for synthesizing (Na0.4K0.1Bi0.5)TiO3 (NKBT)‐based ceramics endowed with exceptional dielectric stability at elevated temperatures. The high‐entropy effect induces a random tilt in the oxygen octahedra of NKBT ceramics, leading to a broad dielectric response characterized by diffuse phase transitions. By weakening the dielectric abnormal peak at Ts of BNT, the dielectric stability of high‐entropy NKBT ceramics is significantly enhanced. Notably, at 100 kHz, the temperature stability range of (Na0.4K0.1Bi0.5)(Ti0.65Zr0.1Sn0.15Hf0.1)O3, synthesized through the traditional solid reaction method, reaches an impressive 311°C, surpassing undoped NKBT by 257%. This significant enhancement underscores the feasibility of our high‐entropy strategy in improving dielectric performance. Our work demonstrates a straightforward and cost‐effective method for significantly improving the dielectric temperature stability of NKBT ceramics. [ABSTRACT FROM AUTHOR]

Ba0.95Sr0.05Ca5Ti2Nb8O30 sample was prepared by solid-state reaction technique to investigate structural, optical, magnetic and dielectric properties via performing different characterizations. XRD reveals the orthorhombic structure with Pbcn space group along with Rietveld refinement. Grain size of the bulk sample was carried out by SEM, which is 1.25μm. Then, microstructural correlated with optical by means of Raman, FTIR and PL spectroscopies. Raman studies reveal the presence of different modes along with band assignments. FTIR and PL studies reveal the bonding modes of A- and B-site atoms, which give the energy band gap around 2.969, 2.441 and 2.012 eV for different bond contributions. The magnetic property was carried out by VSM. The dielectric properties, as a function of frequency and temperature, were carried out and reveal that the bulk sample can be used as storage devices. The modulus spectroscopy was calculated from dielectric studies to analyse electrical properties. [ABSTRACT FROM AUTHOR]

Sol–gel synthesis method was employed to fabricate nanocomposites of (Dy, Hf) co-doped 0.8BiFeO3–0.2CaTiO3 (Bi0.75Dy0.05Fe0.80O3–Ca0.20Ti0.18Hf0.02O3/BDyFO–CTHfO composite). Structural analysis, utilizing X-ray diffraction and Rietveld refinement with Fullprof software, confirmed a rhombohedral structure with space group R3c and an orthorhombic structure with Pnma space group. Particle size determined through Scherrer's formula was ~15 nm. FESEM studies revealed irregular and slightly dense inhomogeneous grains. Dielectric permittivity (ε) and tangent loss (tan δ) were investigated as functions of frequency from 100 Hz to 1 MHz at different temperatures ranging from 303 to 663 K. The dielectric dispersion behaviour was attributed to Maxwell–Wagner-type polarization, with a notable anomaly in dielectric permittivity observed near the magnetic phase transition temperature (TN ~ 643 K) of BiFeO3. Frequency-dependent ac conductivity exhibited low-frequency dispersion following Jonscher's power law. Presence of ferroelectricity was confirmed by the polarization–electric field (PE) loop. Magneto-dielectric characteristics were assessed in a frequency range of 100 Hz–1 MHz under a magnetic field of 0–2 Tesla. Impedance spectroscopy highlighted electrical properties, distinguishing grain and grain boundary contributions via Nyquist plot with respect to the magnetic field. The BDyFO–CTHfO composite demonstrated significant absorption and ~ 25% transmittance in the visible spectrum. The material exhibited a band gap (Eg) of 1.97 eV, suggesting potential applications in ultrafast optoelectronic devices. [ABSTRACT FROM AUTHOR]

This study employed sol–gel technique to synthesize CuOx-ZnO1-x nanocomposites with varying concentrations of CuO (x = 0, 0.25, 0.50, 0.75 and 1.00). The resulting samples were analysed using X-ray diffraction (XRD) to confirm the presence of hexagonal wurtzite ZnO and monoclinic CuO phases. Scherrer's formula and W–H plot were used to determine crystallite size and microstrain, revealing a reduction in crystallite size from 37 to 23 nm with increasing CuO concentration. Optical analysis showed a visible spectrum absorbance and a decreasing optical band gap from 3.25 to 1.54 eV with higher CuO concentrations, impacting photovoltaic and optoelectronic applications. Dielectric studies demonstrated Maxwell–Wagner interfacial polarization across a frequency range (100 Hz–1 MHz) and temperatures (303–573 K), while AC conductivity exhibited low-frequency dispersion revealing enhanced properties with CuO addition. Overall, this study provides valuable insights into CuO-induced modifications in ZnO nanostructures, informing the design of materials with enhanced optical and electrical properties for advanced optoelectronic technologies. [ABSTRACT FROM AUTHOR]

In this work, we theoretically and experimentally study the induction of electromagnetic forces in an opal-based magnetic photonic glass, where light normally impinges onto a disordered arrangement of SiO2 spheres by the aggregation of Fe3O4 nanoparticles. The working wavelength is 633 nm. Experimental evidence is presented for the force that results from forced oscillations of the photonic structure. Finite-element method simulations and a theoretical model estimate the magnetic force volumetric density value, peak displacement, and velocity of oscillations. The magnetic force is of the order of 56 microN, which is approximately 500-times higher than forces induced in dielectric optomechanical photonic crystal cavities. [ABSTRACT FROM AUTHOR]

The solid-state reaction approach was used to synthesize Ba0.95Sr0.05Ca5Ti2−xMxNb8O30 (where M represents Fe and Mn and x is 0 and 0.05) in order to compare the variations in the structural and dielectric properties of the ferroelectric material. The structural investigation was carried out using x-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The orthorhombic structure with Pbcn space group revealed by the XRD investigation was validated by Rietveld refinement. The FTIR spectroscopy results were in good agreement with the reported phase. Analysis of the electrical properties was carried out by complex impedance spectroscopy. The results of transition metal doping with both Fe and Mn with regard to the dielectric permittivity as a function of frequency showed an improvement in the dielectric characteristics, while Mn exhibited a higher dielectric constant than Fe. The pure sample showed a lower transition temperature than the Fe- and Mn-doped sample. Analysis of the magnetic characteristics obtained from vibrating-sample magnetometry (VSM) revealed that doping enhanced the magnetic properties. This approach thus shows excellent potential for high-temperature operation, achieving good temperature stability via transition metal doping. [ABSTRACT FROM AUTHOR]

The work conducted in this study was designed to establish achievable testing tolerances for non-destructive pavement density measurements using Density Profiling Systems (DPSs). Nine and six sensors were used to determine the precision of repeatability and reproducibility in the laboratory and the field, respectively. A minimum of six sensors (considered in this study as independent laboratories) were needed to comply with the minimum number of participants required in the current ASTM standard practice (ASTM E691). The methodology included the development of laboratory precision evaluation with a total of nine sensors and two different mixtures (9.5 mm fine-graded mix, 19.0 mm coarse-graded mix) compacted at four density levels (97%, 94%, 91%, and 88% of Gmm). For the field portion of this study, pavement sections built at the National Center for Asphalt Technology (NCAT) Test Track in 2021 served as experimental variables. These sections were built with fine-graded asphalt mixtures and open-graded mixes as wearing courses. Additionally, the pavement sections included three underlying materials: new asphalt (binder layer), milled asphalt surface, and granular base, with thicknesses ranging from 3.8 to 13.9 cm. Density profile testing was conducted at two locations: within the mat (center of the lane) and along the joint. Computed precision statements regarding dielectric values within and between laboratories were about double for field results compared to laboratory results. However, when converted to density, the statements were significantly below the reported statements for Bulk Specific Gravity and Vacuum Sealing in the laboratory and Nuclear and Electromagnetic density gauges in the field. [ABSTRACT FROM AUTHOR]

This paper reports the structural, dielectric, electrical, and multiferroic properties of Bi2FeNiO6 (BFNO) double perovskite synthesised using a sol-gel modified combustion technique. Its calcination temperature, 873 K, was determined using the mass variation in the TGA curve. Structural characterisation was conducted with the X-ray diffraction technique and the perovskite was found to adopt a cubic structure with space group Fm 3 ¯ m (#225). Synchrotron-based powder angle dispersive X-ray diffraction (ADXRD) measurements were carried out to analyze the structural stability with temperature variation (RT-773 K). SEM studies revealed nearly cubic nanostructures with an average grain size of ~54 nm. EDS and XPS studies confirm the stoichiometric and electrical neutrality of the compound, respectively. The ε vs T curve shows the ferroelectric Curie temperature to be around 732 K, corroborating an exothermic peak observed in the DSC curve around the same temperature. The M-H curve and PE loop show the coexistence of ferroelectric and ferromagnetic properties in the as-prepared Bi2FeNiO6 at room temperature. Highlights: Citric acid-assisted Sol-gel modified combustion technique was implemented to synthesise Bi2FeNiO6 double perovskite. Strong coupling between unpaired electrons of the t2g and eg subshells in the Fe and Ni ions, respectively, is responsible for the magnetic phase transition shift to a higher temperature. The PE loop shows the sample is ferroelectric with remanent polarisation Pr = 1.6 μC/cm2. The ferroelectric transition was found at 733 K and is shown with a temperature-dependent dielectric constant curve. It exhibits room-temperature multiferroic properties with a semiconducting nature. [ABSTRACT FROM AUTHOR]

Bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) ceramics are expected to replace traditional lead-based materials because of their excellent ferroelectric and piezoelectric characteristics, and they are widely used in the industrial, military, and medical fields. However, BNT ceramics have a low breakdown field strength, which leads to unsatisfactory energy storage performance. In this work, 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 ceramics are prepared by the traditional high-temperature solid-phase reaction method, and their energy storage performance is greatly enhanced by improving the process of buried sintering. The results show that the buried sintering method can inhibit the formation of oxygen vacancy, reduce the volatilization of Bi2O3, and greatly improve the breakdown field strength of the ceramics so that the energy storage performance can be significantly enhanced. The breakdown field strength increases from 210 kV/cm to 310 kV/cm, and the energy storage density increases from 1.759 J/cm3 to 4.923 J/cm3. In addition, the energy storage density and energy storage efficiency of these ceramics have good frequency stability and temperature stability. In this study, the excellent energy storage performance of the ceramics prepared by the buried sintering method provides an effective idea for the design of lead-free ferroelectric ceramics with high energy storage performance and greatly expands its application field. [ABSTRACT FROM AUTHOR]

In this manuscript, a new method for the synthesis of CaCu 3 Ti 4 O 12 (CCTO) perovskite was adopted via co-precipitation followed by calcination processes. The co-precipitation route was employed to synthesize calcium and copper oxalates precipitated on the TiO 2 surfaces and the calcination technique at different temperatures was utilized to follow the single-phase formation. Differential thermal analysis-thermogravimetry (DTA-TG) were used to estimate the proper calcination temperatures and to follow the precursor′s decomposition stages. X-ray diffraction (XRD) revealed the initiation of titanate formation at 700 °C. The complete formation of single-phase was achieved at 1100 °C. In agreement with the XRD measurements, FT-IR spectra confirmed the formation the different phases at different calcination temperatures. The prepared titanate showed giant dielectric properties with values higher than reported in literature. The conductivity measurement indicated semi-conducting properties and revealed a transition agreed well with that obtained in the dielectric properties measurements vs. temperature, attributed to the orientional polarization or change in the entire conduction mechanism from hopping to ionic conduction. The obtained electrical properties enhances the utilization of the entire titanate as capacitors. [ABSTRACT FROM AUTHOR]

In this investigation, our primary objective is to explore the structural, morphological, and electrical characteristics of Bi0.75Ba0.25(FeMn)0.5O3 ceramic material synthesized by the sol-gel method. The prepared sample underwent synthesis through the conventional sol-gel technique. Examination through X-ray diffraction (XRD) unveiled a well-defined rhombohedral structure within the R 3 ´ C space group. Moreover, to evaluate the purity and nano-grain morphology, we utilized energy dispersive spectroscopy (EDX) and scanning electron microscopy (SEM). Electrical assessments were carried out over a frequency span of 100 Hz to 1 MHz and temperatures ranging from 200 to 340 K. Employing the correlated barrier hopping (CBH) model, we analyzed the AC conductivity of our specimen. The activation energy, determined from both DC conductivity and impedance spectra, demonstrated close correspondence, suggesting that both conductivity and r laxation processes are influenced by similar factors. Notably, the dielectric properties hold significant importance, potentially rendering our sample suitable for electronic applications. Furthermore, we calculated thermodynamic parameters, such as enthalpy (ΔH), entropy change (ΔS), and free energy of activation (ΔF), offering deeper insights into the material's behavior and conductivity mechanisms. [ABSTRACT FROM AUTHOR]

Polyrotaxane (PR) has garnered increasing attention due to its unique structure and exceptional performance. In this study, a polypseudorotaxane (PPR) initiator was prepared through the self-assembly of bromine-capped Pluronic F68 and β-cyclodextrins (β-CD) in water. Polyrotaxane-containing triblock copolymers (PR copolymers) were successfully synthesized by atom transfer radical polymerization (ATRP) of butyl methacrylate (BMA) using the PPR initiator in the presence of Cu(I)Br/PMDETA. The structure of the PR copolymers was thoroughly characterized using infrared spectroscopy (IR), proton nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC). The mobility of β-CD in the PR copolymers was demonstrated through dielectric measurements. Mechanical tests, including tensile strength assessments, thermal mechanical analysis, and dynamic mechanical analysis, confirmed the excellent mechanical properties and good processability of the PR copolymer, attributed to the PBMA blocks. Furthermore, the mechanical properties were found to be modulated by the motility of the threaded β-CDs. Consequently, the superior mechanical properties and the high mobility of the threaded β-CDs suggest promising potential for the as-prepared PR polymer in various advanced applications. [ABSTRACT FROM AUTHOR]

Spinel ferrites are vital in developing next-generation technologies with potential applications covering the medical, electronic, and material industries. Nickel-cadmium spinel ferrites are soft magnetic materials having lots of applications ranging from electronics and magnetic to sensors industries. Herein, we developed cadmium-substituted spinel ferrites (Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4) and their nanocomposite with polymer polyvinyl alcohol (PVA). The results evidently indicate that the successfully developed Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4, which also confirmed the loading of PVA onto the Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4 materials. XRD results confirmed orthorhombic single-phase structure. The optimal particle size was 27.22 nm, and the minimum was 21.25 nm, respectively, as shown by Ba 0·5 Ni 0·1 Cd 0·4 Fe 2 O 4 (x = 0.4) and PVA composite of Ba 0·5 Ni 0·2 Cd 0·3 Fe 2 O 4 (x = 0.3). It was also observed that the composites showed lower particle size than nano-ferrites. Spectral analysis (Fourier Transform Infrared Spectroscopy) confirmed the formation of spinel ferrites by detecting the M − O bonds in the 400-800 cm−1 region. υ 1 and υ 2 were appeared in the range 560–609 cm−1 and 439-466 cm−1, corresponding to M-O. The average grain size of spinel ferrites was 0.55, 0.50, 1.03, and 1.31 μ m for Ba 0·5 Ni 0.5-x Cd x Fe 2 O 4 (x = 0.1, 0.2, 0.3, and 0.4) spinel ferrites. Dielectric parameters revealed that these materials are suitable for high-frequency devices due to their low dielectric loss, high quality factor, short relaxation time, and diverse responses. [ABSTRACT FROM AUTHOR]

The study examined the chemical structure of azo-based liquid crystalline compounds that were altered to form a branch of cyclotriphosphazene. Moreover, the research explored the interplay between their mesomorphic and dielectric properties. The structures of the compounds were defined by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and CHN elemental analysis. Only intermediates 2a–e and cyclotriphosphazene compounds 4d–e were mesogenic with smectic A (SmA) and smectic C (SmC) phases, respectively. Intermediate 2d and compound 4d were used as representative samples to determine the type of liquid crystal, which was confirmed through X-ray diffraction (XRD). The calculated d/L ratios for both compounds were 1.69 and 0.76, respectively, indicating that d was approximately equal to L (d ≈ L ≈ 1). This finding suggests that the SmA and SmC phases observed under polarized optical microscope (POM) are arranged in a monolayer. For the dielectric study, only compounds 2d–e and 4d–e were proceeded and compared for dielectric characteristics testing. The dielectric constants and dielectric loss factors of these four compounds were measured over the frequency range of 100 Hz to 0.1 MHz at room temperature. The dielectric constant trend decreased with the increasing frequency. Meanwhile, the dielectric loss showed two types of trends. The first trend was identical to the dielectric constant trend, in which the dielectric loss decreased as the frequency increased. However, in the second trend, the dielectric loss began to rise with the increase in frequency and then began to fall gradually after reaching a certain peak. Meanwhile, compounds 4d and 4e had low dielectric constants and losses due to the effect of hexasubstituted cyclotriphosphazene that had been attached as a core. [ABSTRACT FROM AUTHOR]

Bismuth layered structure ferroelectrics (BLSFs), also known as Aurivillius phase materials, are ideal for energy-efficient applications, particularly for solar cells. This work reports the first comprehensive detailed theoretical study on the fascinating structural, electronic, and optical properties of XNb2Bi2O9 (X = Ca, Ba, Be, Mg, Sr). The Perdew–Burke–Ernzerhof approach and generalized gradient approximation (GGA) are implemented to thoroughly investigate the structural, bandgap, optical, and electronic properties of the compounds. The optical conductivity, band topologies, dielectric function, bandgap values, absorption coefficient, reflectivity, extinction coefficient, refractive index, and partial and total densities of states are thoroughly investigated from a photovoltaics standpoint. The material exhibits distinct behaviors, including significant optical anisotropy and an elevated absorption coefficient > 105 cm−1 in the region of visible; ultraviolet energy is observed, the elevated transparency lies in the visible and infrared regions for the imaginary portion of the dielectric function, and peaks in the optical spectra caused by inter-band transitions are detected. According to the data reported, it becomes obvious that XNb2Bi2O9 (X = Ca, Ba, Be, Mg, and Sr) is a suitable candidate for implementation in solar energy conversion applications. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) has recently been actively investigated as a potential power cable insulation substitute for crosslinked polyethylene (XLPE). This is mainly due to PP's higher thermal withstand capability over XLPE. Notably, PP has much higher stiffness than XLPE and therefore needs to be modified with tougher materials to reduce its overall stiffness while maintaining its desirable dielectric properties. To date, many investigations have been conducted on the mechanical and dielectric effects of PP blended with various copolymers. Nevertheless, systematic investigations on the dielectric effects of PP blended with ethylene‐based copolymers having different ethylene contents are less explored. The current work therefore reports on the impact of different ethylene contents of ethylene‐based copolymers on the breakdown performances of PP. The findings reveal that PP blended with a copolymer having a low ethylene content (68.7 wt%) results in at least 11% higher breakdown performance than PP containing a copolymer having a high ethylene content (77.0 wt%). Specifically, PP containing 10 wt% of copolymers having 68.7 wt% of ethylene content results in comparable breakdown performance to XLPE (325 kV mm−1). These results suggest that ethylene‐based copolymers with an appropriately low ethylene content can be blended with PP to achieve desirable breakdown properties. Highlights: PP is blended with copolymers of varying amounts and ethylene contents.PP blended with low amounts of copolymers has good breakdown strength.PP blended with low ethylene level copolymers has favorable breakdown strength.PP blended with copolymers of low ethylene contents is desirable.The breakdown mechanisms are related with the structure and permittivity. [ABSTRACT FROM AUTHOR]

In this work, perovskite oxide SrCeO3 was synthesized using the solution combustion method (SCM). Synthesized samples have been characterized using X‐ray diffraction (XRD), Raman, ultra violet (UV)–visible spectroscopy, and scanning electron microscopy (SEM) techniques. The XRD and Rietveld refinement has confirmed the orthorhombic structure with space group Pnma. The average grain size of this ceramic sample is 1.2 µm. The dielectric constant, dissipation factor, modulus, impedance, and alternating current (AC) and direct current (DC) conductivities were analyzed in the temperature range RT to 600°C and frequency range 20 Hz–2 MHz. Further, it was observed that the role of grain boundaries in dielectric and electrical properties is significant, at low temperatures. The origin of the dielectric relaxation and conduction process is the same. The activation energy for DC conduction (Edc) was found to be.79 eV. Electrical conduction/relaxation is assigned to the diffusion of doubly ionized oxygen (Vo··). The value of DC conductivity (1.2 × 10−3 Ω−1 cm−1 at 600°C) and activation energy of.79 eV is very close to the values reported for doped CeO2‐based oxide ion conductors for SOFCs. This study has demonstrated that SrCeO3 can be an alternative candidate for the oxide ion conductor electrolyte application and the potential to be used as a thermally stable capacitor application for microwave dielectric applications. [ABSTRACT FROM AUTHOR]

The electrical properties of high‐purity magnesium oxide (MgO) samples sintered between 1500 and 1650°C were investigated up to 800°C. Dielectric constant, loss tangent and electrical conductivity were measured between 25 and 800°C. Optimum electrical properties were obtained for the sample sintered at 1600°C. The impurities in polycrystalline and single crystal MgO were discussed to understand their effect on electrical properties and the role of grain boundaries. Higher dielectric losses of polycrystalline samples as compared to the single crystal MgO were attributed to the presence of grain boundaries. MgO could be a useful dielectric material for capacitor applications up to 600°C. [ABSTRACT FROM AUTHOR]

This study presents the characterization and optimization of BaTiO3-doped ZnO-based varistors for electrical and electronic applications. The varistors were prepared using a conventional ceramic procedure and were sintered at a temperature of 1,000 °C with different concentrations of BaTiO3 (0 and 3 mol%) added to the Bi2O3/ZnO-based varistor composition (99.5 mol% ZnO and 0.5 mol% Bi2O3). The results showed that the addition of BaTiO3 led to the formation of various oxides and solid solutions, such as Bi12TiO20, BaTiO3, and (Bi2O3)0.80 (BaO)0.20. The dielectric constant and grain size decreased with increasing BaTiO3 content, while the non-linearity coefficient, electric fields (Eb) increased, and dielectric loss (Tand) decreased. The optimized varistor contains 2 mol% BaTiO3 and an electric field of 148.08 V/mm, which are superior to those of the BaTiO3/Bi2O3/ZnO-based varistor. During this study, we were able to observe that a slight addition of BaTiO3 will increase the breakdown voltage and the coefficient of nonlinearity and this will allow us to develop lowdimensional varistors and install them in the high-voltage domain. [ABSTRACT FROM AUTHOR]

A material that composed a components either nanoscale or nano-sized and have improved dielectric characteristics is called a nanocomposite material for dielectric applications. Dielectric materials can sustain an electric field with little energy loss since they are non-conductive. This study examined in detail the optical, morphological, and structural characteristics of materials made of tin dioxide/graphene oxide (SnO2/GO), with an emphasis on the potential uses of these materials as dielectrics. The crystalline nature of the materials was revealed by using X-ray diffraction (XRD) to clarify the structural properties of the produced nanocomposites. This was done in a systematic manner. For the purpose of enhancing dielectric characteristics, morphological investigations using scanning electron microscopy (SEM) reveal a well-dispersed and linked structure. A significant defect density is discovered in the composite, and the energy dispersive X-ray spectroscopy (EDX) spectrum's exclusive Tin (Sn), carbon (C), and oxygen (O) content confirms the originality of the sample. The optical properties of the nanocomposites were studied using photoluminescence (PL) measurements, and ultraviolet-visible spectroscopy (UV-Vis) of the nanocomposite revealed a 3.7 eV energy of the band gap that is consistent with SnO. The tiny high fault density and grain size are in charge of the dielectric constant's observable increase. The synthesized SnO2/GO nanocomposite shows promising properties use in dielectric applications. [ABSTRACT FROM AUTHOR]

Composites derived from polyvinylidene fluoride (PVDF) play an important role in advanced dielectric energy storage due to their outstanding characteristics, including remarkable flexibility, low density, high dielectric permittivity, and superior dielectric breakdown strength. The strategically designed composition significantly enhances the energy storage performance, such as discharge energy density (Ue) and charge–discharge energy efficiency (η). Consequently, we employed the solution cast method to create flexible composite films, combining PVDF polymer with strontium tungstate (SrWO4) ceramic. X-ray diffraction analysis revealed the coexistence of α and electroactive β phases in PVDF. These phases have a substantial effect on the dielectric characteristics and energy storage density of composites. Flexible nanocomposites of PVDF and SrWO4 exhibit high dielectric constant and low tangent loss. Micrographs obtained using scanning electron microscopy (SEM) showed that the morphology of the composite varies according to the amount of filler present in the matrix. The impedance spectroscopy method yielded intriguing findings regarding the roles of both grain and grain boundaries in the overall resistance characteristics of the composites. The frequency-dependent behavior of alternating conductivity follows Jonscher's power law. The hysteresis loops indicate that the nanocomposite film maintains favorable ferroelectric properties. The present study suggests some promising applications for advanced dielectric capacitors and energy storage devices. [ABSTRACT FROM AUTHOR]

Bimetallic nanostructures can exhibit significant broadening of Mie resonances compared to monometallic nanoparticles. Here, we study these materials using Electron Energy Loss Spectroscopy at a single particle level. This technique is immensely effective to probe direct structure-property correlation of nanoparticles. We are thus able to confirm the broadening of Mie resonances at a single particle level. This effect is analyzed in the context of emergence of a new dielectric constant that originates from metallic interfaces. We employ Coronado-Schatz corrections to the usual dielectric constants of the constituent metals to quantitatively simulate these materials. The resultant materials thus exhibit optical cross-sections that are 38.5 % and 4.2 % of the gold and silver nanoparticle optical cross-section at 2.5 eV and 3.45 eV, respectively. A strong agreement between theory and experiment is observed. We also confirmed the effectiveness of our approach for nanoparticles with different morphologies as well as different compositional ratios. Our study suggests an effective strategy to regulate the dielectric properties of bimetallic nanostructures through interface engineering.

This paper reports the dielectric behaviour and electrical conduction properties of Y6-xBa4Ybx(SiO4)6O2 (YBaSiO: xYb) compounds. The Scanning Electron Microscopy (SEM) was utilized to obtain the surface microstructure of the compound. The micrographs showed both the circular and elongated shape of grains and their random distribution. The Fourier Transform Infrared Spectroscopy (FTIR) was used to confirm the presence of bond formations in the compounds. From the spectra, it was observed that the peaks at 690 cm−1 and a band from 850 cm−1 to 998 cm−1 are due to the stretching frequency of Y-O molecules and Si-O molecules, respectively. The peak centred at 1464 cm−1 is of vibration modes of Ba2+ions. These peaks confirmed the formation of oxy-apatite compounds. Both the dielectric permittivity and dielectric loss, decreases with increasing values of frequency due to reduction in the polarization effects on the higher side of frequency. This is because the dipole orientation lags with the rapidly reversing alternating current (ac) field. The value of dielectric loss was found to range between, 0 – 3.5 in frequency ∼ 100 Hz and 0 – 0.5 in frequency ∼ 100,000 Hz, up to temperature 500 °C. The impedance value decreases and hence a. c. conductivity increases, at higher frequencies. The increment in ac values followed the universal power law. The Nyquist plot showed that the area under the curves reduces and hence indicates negative temperature coefficient of resistance i.e., NTCR behaviour of compounds. The obtained results suggest the utilization of compound in electrical devices as power loss component, solid oxide fuel cells, and capacitors etc.

Barium Bismuth Ferrite nanoparticles having the general formula Ba1-xBixFeO3 were successfully made by the sol-gel system, using nitrates as the fundamental material. Tartaric acid and polyvinyl alcohol were used as chelating agents. The synthesized nanoparticle powder was sintered at 650 ̊C and 750 ̊C for 3 h. Filtering with dilute nitric acid and distilled water is used to remove the impurities. The structural, optical, and dielectric properties were determined at room temperature. Using X-ray diffraction (XRD) analysis, structure, lattice parameter, microstrain, and dislocation density were calculated. Using the Scherrer equation, the peak's crystalline size was ascertained. In FTIR, the vibrational modes of the octahedral and tetrahedral metal complexes in the sample have been studied using the wavenumber in this range. The synthesized nanocomposite contains morphological features, such as interconnecting agglomerates with spherical, irregular, or non-uniform elongated shapes, as demonstrated by SEM images. The activation energy for relaxation and activation energy for conduction was measured from the Cole-Cole plot and the AC conductivity versus frequency plot respectively. The determined activation energies from the two investigations were relatively close to one another. The Barium Bismuth Ferrite nanoparticles samples at room temperature indicate that the samples have implicit candidates for information storage devices for spintronic devices. In the high frequency range, all samples depending upon the temperature demonstrate excellent dielectric behaviour and small dielectric loss, and with stable dielectric constant, these samples make their prospective for the practical application in spintronic devices the main goal of this work.

Abstract Dielectrics are non‐conducting substances that are primarily utilized to hold electric charges. These materials are widely employed in the field of chemical mechanical, civil and structural engineering, because of their inherent insulating properties. Besides these domains, dielectric materials are also used in electrical and electronic applications. Dielectric materials have shown an ever‐increasing potential in recent years in the fabrication of antennas, sensors, and optical devices that are extensively utilized for on‐body, environmental, robotics, and biomedical applications. With inherent electrostatic shielding, insulation, and dielectric relaxations, these materials are used in intelligent electronic devices used for biomedical applications, smart devices, vehicles, and future IoT applications. Numerous applications necessitate multiple kinds of dielectric, classified based on their polarization, flexibility, thickness, dielectric constant, and specific application. In this extensive research review, the characteristics and various aspects of dielectric materials are discussed, followed by a thorough and detailed review of flexible dielectrics and their usage in flexible electronics. Additionally, the practicality and applications of these materials which come from a variety of publications in the literature are also discussed. Moreover, in‐depth study of dieletrics in sensors and RF applications are performed.

Abstract This work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

The integrable substrate for THz modulation directly influences both the quality of films and THz absorption. Currently, the available THz substrate candidate library is still not clear. Here, we have carried out a systematic investigation of commonly used commercial substrates, including Si, quartz SiO2, MgO, Al2O3, GdScO3 and TbScO3 in the range of 0.4–1.6[Formula: see text]THz. It is found that low resistance Si, TSO and GSO are certainly not appropriate for THz light modulation due to their relatively higher absorption and dielectric constant, while the rest show better THz transmittance, low refractive index and loss. However, the dielectric constant and refractive index of high resistance Si are generally two times larger than quartz SiO2, Al2O3 and MgO. Compared with Al2O3 and MgO, quartz SiO2 shows at least 50% lower dielectric constant, refractive index and absorption, making it the best candidate. Our research is believed to build the rich substrate candidate library for THz range light modulation.