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Sr0.975Sm0.025Ti1−xAlxO3 (x = 0, 0.005, 0.01, 0.015, 0.02, 0.025) ceramics were synthesized via solid-state reaction. The sample with an x = 0.005 doping concentration exhibited the optimal dielectric properties, with an electric constant of 8832 and a dielectric loss of tanδ = 0.019, measured at 1 kHz and room temperature. This sample also exhibited excellent frequency stability (ranging from 100 Hz to 1 MHz) and temperature stability (from room temperature to 200 °C). The activation energy calculation for the dielectric modulus relaxation peak, coupled with XPS results, indicates that in the sample with x = 0.005, there is a significant presence of oxygen vacancies and Ti3+ ions, which form defect complexes (Ti3+ − V O.. −Ti3+). These complexes restrict the delocalization of electrons, leading to electron pinning. Consequently, the sample demonstrates a high electric constant and low dielectric loss. In addition to the defect complexes, high grain boundary resistance reduces dielectric loss and enhances temperature stability. The findings of this study offer crucial conceptual insights for the defect engineering of complex perovskite materials, facilitating the development of doped strontium titanate ceramics with colossal permittivity. [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]

The report in the article has emphasised the characterisation (structural analysis, sample microstructure, dielectric, impedance, and modulus) of a layered perovskite ceramic oxide LiNdSnO4 (LNSO) prepared by solid-state reaction method. The compound formation and phase identification with multiphase are confirmed using X-ray diffraction (XRD). This XRD shows that the material contains LNSO as the predominant and minor impurity phases. The crystallite size and strain are calculated to be 106 nm and 0.001, respectively. SEM study shows that the grains formed in the sample are a combination of the big (~ 2.23 μm) and small grains (~ 0.95 μm). The ac conductivity follows the Jonscher's power law. The non-Debye type of relaxation mechanism and the hopping mechanism are shown by the shifting of the curve in the high-frequency zone in modulus spectra. The FT/IR study demonstrates the presence of a vibrational band in each element of the sample. The dielectric constant and loss increased sharply at 300 °C. The maximum activation energy (0.5598 eV) was found at a lower frequency. Nyquist spectrum indicates the presence of grain and grain boundary properties of the material. The semicircular behaviour of impedance spectra demonstrated that the material might be semiconducting. This study concluded that the compound is useful for NTCR thermistor devices. [ABSTRACT FROM AUTHOR]

This study explores the impact of crystallite size on the opto-dielectric properties of LiCu0.5Fe2-yCeyO4 (y = 0.0, 0.01, 0.02, 0.03, 0.04) nanospinel ferrites (NSFs) synthesized via sol–gel auto-combustion. X-ray diffraction (XRD) analysis confirmed the crystalline nature and phase purity, revealing variations in crystallite size within the nanoscale range. Fourier-transform infrared spectroscopy (FTIR) provided insights into chemical bonding, affirming the composition and structure reliability. Morphological characterization via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the nanostructure, highlighting the influence of crystallite size on particle morphology, shape, and size distribution. Energy-dispersive X-ray spectroscopy (EDX) verified the presence of expected elements, with elemental composition offering spatial distribution insights. Inductively coupled plasma (ICP) analysis quantified elemental concentrations, focusing on Li, Cu, Fe, and Ce. Optical properties, including UV–vis absorption spectra, were measured to assess band gap energies. Dielectric measurements across a range of frequencies provided insights into the pure Li-Cu NSFs and Ce3+ doped Li-Cu NSFs dielectric response, revealing variations in dielectric constant and loss tangent with changing crystallite size. The findings highlighted the significant role of crystallite size in modulating both energy band gap and dielectric properties, essential for applications in high-frequency, photonics, electronics, and sensor technologies. [ABSTRACT FROM AUTHOR]

Magnetoelectric materials are considered as the most promising materials for multifunctional device application. In this study, we report a polycrystalline 0.9 PbZr0.52Ti0.48O3-0.1 NiFe2O4 (0.9PZT-0.1NFO) particulate composite prepared via cost-effective solid-state reaction route. The detailed structural analysis is done by performing Rietveld refinement technique. Both X-ray diffraction and Scanning Electron Microscopy confirmed the presence of both ferrite and ferroelectric phases without any interdiffusion. The magnetic and AC electrical properties like conductivity, dielectric constant, dissipation factor (dielectric loss), and impedance spectroscopy analysis were studied in detail with different frequencies and temperatures. A relatively high dielectric constant at low frequencies and high temperatures was obtained. The transition temperature is found to be 440 °C, which is greater than that of pure PZT. Complex impedance spectroscopy and modulus spectroscopy showed the occurrence of relaxation phenomena due to both grain and grain boundaries. The ac conductivity was studied to understand the conduction mechanism in the prepared sample. The composite exhibits the NTCR behavior. The PE loop confirms the ferroelectric property of the prepared sample. The MH loop shows a well-saturated curve, in which the experimental value of saturation magnetization is well-matched with the value obtained from fitting of MH loop to Law of Approach to Saturation. [ABSTRACT FROM AUTHOR]

We prepared bulk samples of SrLaLiTe1-xGdxO6; 0 ≤ x ≤ 0.3, using the solid-state method. Measurements carried out on the XRD data recorded at room temperature highlighted changes corresponding to the volume of the unit cell and angle β. Specifically, the undoped composition described a structure of the ordered type containing Li+ and Te6+. Calculations of the octahedral tilt angle indicated a transition from cubic to monoclinic symmetry, accompanied by bending and tilting of the B-O-B'(B = La, B' = Te/Gd) octahedra. FTIR measurements confirmed the existence of molecular bonds in all compositions. UV–visible spectroscopy results indicated a reduced bandgap energy, suggesting enhanced conductivity in the doped samples. SEM and EDX confirmed the elemental composition and revealed particle clustering. Impedance spectroscopy analysis demonstrated increased AC conductivity at higher frequencies. Additionally, a decrease in the grain resistance indicated single dielectric relaxation behavior. A relaxation phenomenon of the non-Debye type was revealed from the Cole–Cole plots attributed to the presence of imperfections within the samples. Dielectric properties showed a reduction in dielectric loss and constant, which was dependent on frequency, attributed to the decrease in overall polarization. [ABSTRACT FROM AUTHOR]

A 1-3 type poly(vinylidene-trifluoroethylene)/lead zirconate titanate (P(VDF-TrFE)/Pb(Zr0.52Ti0.48)O3) piezoelectric composite is prepared using a two-step hot-pressing method, showing a considerable dielectric constant (εr ~ 4614) and a very low dielectric loss factor (tanδ) of 0.05 and at 100 Hz are obtained in PZT/P(VDF-TrFE) sheet with a thickness of 1.2 mm. Because the polarized P(VDF-TrFE) has a clamping pressure on the engineered columnar architecture by the inverse piezoelectric effect, the elongation of PZT is improved by suppressing its lateral vibrations, which is well expressed by COMSOL simulations. As such, an attractive electrical coupling coefficient (kt) of 0.733 is achieved with specific geometric modifications to the PZT/P(VDF-TrFE) sheets. These findings indicate that piezoelectric P(VDF-TrFE) to replace conventional epoxy resin as the polymer matrix offers a route to construct 1-3 type piezoelectric composites. [ABSTRACT FROM AUTHOR]

The orthophosphates materials are one of the most important groups in the field technologically advanced materials that are accessible, inexpensive, and environmentally friendly. This materials are of great demand due to their various optoelectronic applications in recent years. In this study, a solid-state method was employed to synthesize the AgCoPO4 orthophosphate sample. Analyzing the XRD pattern, of the studied compound, confirms the triclinic phase with the P 1 ¯ space group. The examination of SEM analysis and energy dispersive spectroscopy (EDS) revealed the same morphology and different particle sizes. As for the EDX analysis, all chemical elements were detected and found in their appropriate ratio. Besides, the impedance spectroscopy measurements conducted at 100 Hz to 5 MHz and 473–673 K are used to investigate the electrical and dielectric properties of the AgCoPO4 compound. The frequency dependence of the conductivity of alternating current is explained using Jonscher's law. The calculated activation energy is in accordance with Arrhenius's behavior based on DC conductivity, which was determined to be 0.93 (2) eV. The primary transport mechanism is governed by the correlated barrier hopping model. A comparative study of impedance and modulus responses versus frequency suggests Cole–Cole behavior. deep investigation of the electric and dielectric performances demonstrated a significant dielectric constant (ε′ ∼ 104) at low frequencies and low dielectric loss at high frequencies. Thus, it highlights its exceptional dielectric potential, particularly in applications related to electronic capacitors. [ABSTRACT FROM AUTHOR]

Flash sintering is considered a promising energy-saving and efficient technology for preparing high-temperature ceramics. The effects of limited current on flash sintering parameters, microstructure, and electrical properties of (La1/2, Ta1/2)0.02Ti0.98O2 ceramic were investigated by the XRD, SEM, XPS, and precision impedance analyzer. With limiting current increase, the grain size of flash sintering sample increases gradually, and the relative density increases first and then decreases. The average grain size is about 1 μm, and the highest relative density is 96.9%. Joule heating runaway and oxygen vacancy defect lead to rapid densification of flash sintering La and Ta co-doped TiO2 ceramics. According to the EPDD model, doped La3+ and Ta5+ ions increase the concentration of oxygen vacancies and free electrons, lead to local polarization of carriers, and obtain a giant dielectric constant of ε' = 7.6 × 104 and low dielectric loss of tanδ = 0.11. At high temperature, electrons break free from the constraints of defect clusters and accumulate at the interface, leading to interface polarization due to the IBLC model. The giant dielectric properties originate from the combined effect of EPDD and IBLC model. [ABSTRACT FROM AUTHOR]

A series of single phase (Na1/2Eu1/2)xCa1−xCu3Ti4O12 (x = 0, 0.01, 0.05, 0.1, 0.2, 0.3, 0.35, 0.4 and 0.45) ceramics with different doping amounts were successfully prepared by high temperature solid-state reaction method. The microstructure, ion valence, and dielectric properties of the ceramics were systematically studied. The results indicated that with the increase of Na+ and Eu3+ ions concentration in (Na1/2Eu1/2)xCa1−xCu3Ti4O12 ceramics, Na and Eu elements accumulated at the grain boundaries of ceramics, thereby increasing the insulation of grain boundaries and effectively reducing the dielectric loss of the ceramics. However, the presence of Cu+ in (Na1/2Eu1/2)xCa1−xCu3Ti4O12 (x ≥ 0.3) ceramics with high doping content could affect the polarization mechanism inside the ceramics and improve their dielectric properties. The dielectric constant of (Na1/2Eu1/2)0.3Ca0.7Cu3Ti4O12 ceramics was as high as 25 282, with a dielectric loss of 0.061 (at room temperature and 10 Hz), and it had good dielectric stability. [ABSTRACT FROM AUTHOR]

In this work, zinc sulfide (ZnS) QDs were synthesized using green technique with the help of Tabernaemontana divaricata flower extract as capping/stabilizing agent, characterized by different physical techniques, like XRD, FESEM, EDX, TEM, FT-IR, XPS, UV–Vis–NIR, and PL, and were compared with their pristine analogue. From XRD analysis, it is observed that the size of the synthesized ZnS QDs lie in 1.79–1.46 nm range and with addition of flower extract particle size decreases. FT-IR analysis indicated the functional groups present in the synthesized QDs. The direct energy band gap (3.21–3.51 eV) values as well as the refractive index values (2.28–2.33) of the QDs were calculated utilizing the absorption data. Due to various defect levels present in the ZnS QDs within the energy band gap, four peaks (three in visible and the other in NIR region) were observed in the PL spectra. Surface morphology and elemental composition of the particles were understood from FESEM and EDX studies. Dielectric constant, loss, and ac and dc conductivity of the materials were studied. At room temperature, all synthesized ZnS materials exhibited high dielectric constant ( ε r ) values in the low-frequency region. It is found that ε r values for pristine ZnS QD (~ 23,000) are much higher than the green ZnS QDs (~ 100–800) where overall dielectric loss is less than 2 which decreases with QD size. Results obtained from the characterization studies conducted on pristine and green-synthesized ZnS QDs elucidate that it is possible to effectively control the size, optical, and dielectric properties of the potentially important ZnS QDs through green synthesis technique. [ABSTRACT FROM AUTHOR]

Recently, ceramic patch antennas have been intensively researched for mobile communication systems. This work shows the unique use of Bi0.5Na0.5TiO3 (BNT) ceramic in microstrip patch antenna substrates for 8–12 GHz operation. The synthesized ferroelectric perovskite-based substrate of thickness t = 1.02 mm was utilized to produce the simulated antenna. The relevant electromagnetic parameters of permittivity, permeability, dielectric loss, magnetic loss, and miniaturization factor were studied. Characterization procedures are used to analyze the synthesized sample's crystal structure, local vibration, surface morphology, and elemental analysis. The rectangular-based split ring microstrip patch antenna's reflection loss, return loss, and radiation pattern were calculated using CST Microwave Studio v. 2019. The best yield result of simulation is − 55 dB which corresponds to the fabricated result of about − 25 dB for substrate thickness of t = 1.02 mm. The uniqueness of the synthesized sample has been modified parametrically by modifying its thickness for t = 0.9 mm, t = 1 mm, and t = 1.02 mm among which t = 1.02 mm thickness of the substrate is optimal for optimum results. [ABSTRACT FROM AUTHOR]

This study is dedicated to a comprehensive investigation into the influence of barium strontium titanate (BST) doping on the microstructure, dielectric properties, and electrical behavior of calcium copper titanate (CCTO) ceramics. The research involves a systematic analysis of a series of (1-x) CaCu3Ti4O12 - x Ba0.6Sr0.4TiO3 [(1-x) CCTO/x BST] composite samples, with varying BST ratios (x = 0, x = 0.025, x = 0.075, x = 0.15, and x = 0.2). These composites were synthesized through the solid-state reaction method and subsequently sintered at 1050 °C for a duration of 12 h. The investigation provides detailed insights into microstructural features, dielectric characteristics, and electrical responses, thereby unraveling the intricate correlations between BST content and the resultant material properties. Notably, the sample with x = 0.025 exhibited the highest dielectric constant (εr ≈ 2.71 × 104) and the lowest dielectric loss (tanδ ≈ 0.052) at a frequency of 1 kHz. Furthermore, the optimized composition (x = 0.025) demonstrated exceptional breakdown electric field (Eb ≈ 1284 V/cm) and notable grain boundary resistance (Rgb ≈ 8.8 × 106 Ω). These findings collectively contribute to an enhanced understanding of the impact of BST doping on the distinct characteristics of CCTO ceramics, opening avenues for tailored applications in advanced electronic devices and energy storage systems. [ABSTRACT FROM AUTHOR]

This study investigated the impact of magnesium doping on structural, optical, and dielectric properties of zinc oxide. Magnesium-doped ZnO (Zn1−xMgxO) samples were synthesized and characterized with varying doping levels (x = 0, 0.01, 0.02, 0.03) using solid state reaction, employing techniques including X-ray Diffraction(XRD), Field Emission Scanning Electron Microscopy (FESEM), Impedance Spectroscopy and Diffuse Reflectance Spectroscopy (DRS). The synthesized samples show single-phase hexagonal wurtzite structure, indicating successful doping of magnesium in ZnO lattice. FESEM micrograph revealed voids in doped samples. Doping reduces the dielectric constant of ZnO and shows dielectric loss > 200 °C in doped sample. Magnesium doping decreased ZnO's band gap, altering its electronic properties and optical behavior. Urbach energy increased with doping and inversely linked to dielectric constant. [ABSTRACT FROM AUTHOR]

The Ba0.5Ca0.5EuxFe12−xO19 (x = 0, 0.5, 1.0, 1.5, and 2.0) series of samples with crystallite size 29–38 nm were prepared using the co-precipitation synthesis technique. The X-ray diffraction pattern analysis confirms the hexagonal structure of the Ba0.5Ca0.5EuxFe12−xO19 samples. The value of lattice parameters of the Ba0.5Ca0.5Fe12−xO19: xEu samples increased as compared to the pure Ba0.5Ca0.5Fe12O19 sample. This increase is related to cation substitution i.e., smaller cations (Fe3+ ions) are replaced by larger cations (Eu3+ ions). The crystallite size of the Ba0.5Ca0.5Fe12−xO19: xEu samples decreases continuously with increasing Eu3+ ions substitution. The shifting of octahedral and tetrahedral clusters was observed in the FTIR spectra due to substitution of Eu3+ ions. The photoluminescence (PL) spectra of the Ba0.5Ca0.5EuxFe12−xO19 samples were observed at 365 nm which corresponds to 5D4 – 7F0 transition of Eu3+ ions. The PL spectra shifted toward the higher wave length side for x ≥ 1.0 due to reabsorption. The dielectric dispersion in the Ba0.5Ca0.5EuxFe12−xO19 samples can be understood by Maxwell–Wagner type of interfacial polarization based on Koop's theory. The increased hopping rate at octahedral sites due to the substitution of Eu3+ ions is responsible for a higher dielectric constant. The activation energy of the Ba0.5Ca0.5EuxFe12−xO19 samples was estimated from the temperature dependence of dc conductivity plots. The frequency dependency of ac conductivity of Ba0.5Ca0.5EuxFe12−xO19 samples can be described on the basis of Jonscher's power law and correlated barrier hopping (CBH) model. Below 380 K, the CBH mechanism describes the conduction mechanism, and above 380 K, the conduction mechanism can be understood by small polaron tunneling without overlapping (NSPT) model in the Ba0.5Ca0.5Fe12O19 compound. In the Eu-substituted Ba0.5Ca0.5Fe12O19 compound, only CBH mechanism dominates in the conduction process for all the temperatures. The Ba0.5Ca0.5EuxFe12−xO19 samples exhibit non-Debye dielectric behavior as confirmed by complex impedance spectroscopy analysis. By substituting Eu3+ ions, dielectric constant increases drastically and dielectric loss decreases as compared to pure sample. This indicates that the Ba0.5Ca0.5EuxFe12−xO19 samples can be potentially applied for microwave absorbers. [ABSTRACT FROM AUTHOR]

Herein, the 0.725BiFeO3−0.275BaTi1−xHfxO3 + 1 mol% MnO2 ceramics (x = 0, 0.01, 0.05, 0.10; abbreviated as 0Hf, 0.01Hf, 0.05Hf, 0.10Hf, BF-BTH) were prepared with the conventional technique. Pure perovskite structure of the BF-BTH was obtained with the R and T phases. The bond length and bond angle of ceramics enlarged when doped by Hf, resulting in a distorted structure of the R phase. The introduction of Hf increased the content of the R phase and structural distortion, leading to the enhanced remanent polarization from 14.7787 µC/cm2 for 0Hf to 23.0335 µC/cm2 for 0.10Hf. Therefore, although the coercive field gradually increased, the piezoelectric response was not significantly deteriorated. The d33 value of the BF-BTH showed higher values (130 pC/N to 116 pC/N) over a wide range of components ranging from x = 0 to 0.10. Furthermore, Hf4+ effectively reduced the dielectric loss of ceramics (~ 15.6%). Hf4+-doped BiFeO3-based ceramics provided a clue for reducing dielectric loss and keeping the piezoelectric properties with a wide range of components. [ABSTRACT FROM AUTHOR]

CaCu3Ti4O12 (CCTO) dielectrics can be extremely important potential candidate materials for electrical devices. However, their practical application process is somewhat restricted by some longstanding problems, such as insufficient temperature stability and large dielectric loss. Therefore, x wt% SrTiO3 added CCTO ceramics (x = 0, 2, 3 and 4) were prepared via sol–gel route. When x = 3, the ceramic sample exhibits a dielectric constant (ε′) of 2968, a high breakdown field strength of 11.61 kV/cm and a low dielectric loss of 0.009 at room temperature. Excitingly, the ε′ of this modified x = 3 sample shows less than ± 10% variation in the temperature range of − 125 to 150 °C, which meets the commercial standard for X8P capacitors (Δε′ ≤ ± 10% at − 55 to 150 °C). The presence of these excellent properties in this sample is inextricably linked to its high grain boundary resistance and the larger grain boundary activation energy. Therefore, this study shows that the improved samples can promote the application process of CCTO and be adopted in the future for the preparation of excellent ceramic samples. [ABSTRACT FROM AUTHOR]

ZA crystal is synthesized using slow evaporation methodology at room temperature with proper ambience and the crystal is a colourless one which is acquired in 16 days. The single crystalline XRD of ZA with a,b,c and β as 15.099 Å, 9.243 Å, 4.7979 Å, 98.10° and P21/c as space group with monoclinic system and for micro scale (ZAμ), and 100 Gy irradiated micro scales (GZAμ), the a, b, c, β are obtained and macro to micro is by 20 h of milling and irradiation is 100 Gy of Co-60 source over ZA-μ specimen and the powder XRD data is provided. UV-induced/stimulated visible Fluorescence-FL and they cannot be seen by naked eye and the present case lesser emission is due to GZAµ sample of 100 Gy which creates the vacancy sites and the reduced value and increased band gap as 3.4733 eV. The electronic transition of gamma irradiated 100 Gy of ZAµ sample is performed for the UV–visible spectrum, referred for the peak of 876 nm and %T as 91.63% and the cut-off is 243 nm for band gap of 5.1028 eV; whereas the photonic study is relevant for 5.1 eV for GZAµ data. The dielectric is maximum for 413 K and minimum for 343 K and the various is more due to the impact of irradiation of the source and maximum values is 86.4 and minimum value is 5.2. The dielectric loss pertaining to GZAµ is studied as the higher value is 473 K and lower values is 373 K, the Zig-Zag variation is due to the impact of irradiation and the more or less, higher or lower order radius is mainly due to micron level scaling of specimen and Co-60 radiation; the activation energy is calculated and specified from 0.175 to 0.125 range. The major variance is due to vacancy site creation by the dosage of Co-60. The GZAμ material is involved in filter use and the values is 5.0299 microns as the influx- GZAμ estimation for properly pronounced electronic and opto-electronic case. The second order NLO is 1.24; 1.26 and 1.32 times of referenced KDP and is 0.434, 0.441, 0.462 for reference of urea for the ZA-macro; ZA-micro and ZA-gamma irradiated micro and is 86.8, 88.2 and 92.4 mV corresponding to the KDP referenced phase matching impacting the order is GZAμ > ZAμ > ZA-macro ones. [ABSTRACT FROM AUTHOR]

The abundant requirements of smart terminals promote the rapid development of dielectric materials to further realize the integration and miniaturization of electronic devices. In this work, based on a solid-state reaction method, (In0.5Ta0.5)0.1Ti0.9O2 (ITTO) ceramics with dense microstructure, colossal permittivity of 1.18 × 105, and ultralow dielectric loss of 0.0072 were obtained at 1 kHz and room temperature. In addition, the temperature coefficient stability and range of the ITTO ceramics were between ± 3.3% and − 100 to 235 °C, satisfying X9D (− 55 to 200 °C, Δεr/ε25°C < ± 3.3%) requirement at 1 kHz. The dielectric mechanisms could be connected to the electron hopping and internal barrier layer capacitor (IBLC) effects. Thus, the acquired ITTO ceramics have advanced advantages with excellent dielectric properties and temperature stability in the practical applications of microelectronic fields. [ABSTRACT FROM AUTHOR]

Adding nanoparticles (NPs) to a base polymer matrix which is known as nanocomposites results in improving its dielectric properties. In this paper, the evaluation of polyvinyl chloride (PVC)/silica nanoparticles (SiO2) nanocomposites is carried out considering the effect of water absorption. PVC nanocomposites are prepared considering different filler loadings of SiO2 NPs (1, 2.5, 5, and 7.5 wt%). The preparation of PVC/SiO2 nanocomposites is chemically carried out by casting the solution. The chemical structure of PVC/SiO2 nanocomposites after water adsorption is investigated by Fourier transform infrared (FTIR) spectroscopy. The effect of water absorption is carried out by immersing nanocomposite samples in tap water. The AC breakdown strength of PVC/SiO2 nanocomposites is measured before and after water immersion. In addition, both dielectric constant (έ) and loss tangent (tan δ) are measured considering different frequencies before and after the water immersion. The results show that the dielectric properties of PVC/SiO2 nanocomposites are significantly affected by water absorption, where PVC/SiO2 nanocomposite sample with filler loading of 7.5 wt% is found to have lower water absorption compared to the other adopted filler loadings. Under the effect of water absorption, the breakdown strength of the base and PVC nanocomposite samples is decreased, and its value for PVC nanocomposite still exceeds the base polymer. Finally, the dielectric constant and dielectric loss of PVC samples are increased under the effect of water absorption. The increase in dielectric constant and dielectric loss is small at the higher filler loadings. [ABSTRACT FROM AUTHOR]

To solve the problem of corona discharge generated by the stator wire rod of large high-voltage motors, anti-corona technology should be developed rapidly to ensure the safe operation of power generation systems. A nonlinear anti-corona material is often used to coat the primary insulation at the end of the stator rod to improve the unevenness of the electric field and to reduce the problem of shortening the service life of the primary insulation caused by the uneven phenomenon of field strength. It is imperative to study composites with good nonlinear electrical conductivity properties. In this paper, Tetra-needle-like ZnO whiskers (T-ZnOw) with a three-dimensional four-needle three-dimensional structure was added to the montmorillonite/silicon carbide/epoxy (MMT/SiC/EP) composite system to improve the electrical properties of the hybrid system, and T-ZnOw/MMT/SiC/EP micro-nanocomposites were prepared. The result of dispersion and interfacial overlap of inorganic fillers in the matrix was shown by scanning electron microscope. The conductivity, breakdown, and dielectric properties of the composites were tested. The results show that T-ZnOw can constitute an excellent conductive path inside the composite and reduce the threshold field strength of the composite. It improves the electrical conductivity and nonlinear coefficient of the composite. The content of T-ZnOw is 1 phr, which can effectively enhance the breakdown field strength of the composite. Its range of 9 phr reduces the relative dielectric constant and the dielectric loss angle tangent value. [ABSTRACT FROM AUTHOR]

In this work, a novel ceramic sample (1-x) Ca0.9Sr0.1Cu2.9Mg0.1Ti4O12 (CSCMTO) – x SrTiO3 (STO) (with x = 1, 3, and 10 weight%) was suggested by combining two oxide phases to create a new system. All the ceramic samples were prepared by solid-state reactions. The impact of the STO phase on the structure and dielectric properties of CSCMTO ceramic was analyzed through X-ray diffraction, scanning electron microscopy, Raman, and dielectric measurements. The increase in STO content brings about a decrease in mean grain size. The Raman and EDS measurements indicate the presence of STO and TiO2 phases at grain boundaries. The dielectric constant values of ceramic samples range from 103 to 104. They decrease progressively with the addition of the STO phase, accompanied by a reduction in the dielectric loss. The 0.9CSCMTO − 0.1STO reveals the lowest dielectric loss in the order of 0.031 at 10 kHz. Additionally, the STO phase plays a critical role in the enhancement of nonlinear properties. The 0.97CSCMTO-0.03STO shows the best value of breakdown voltage (Eb ≈ 1820 V/cm) as well as the highest nonlinear coefficient (α ≈ 3.55). A heterogeneous microstructure with improved grain boundary properties was shown by impedance spectroscopy. The high grain boundary resistance is responsible for the reduced dielectric loss and improved breakdown voltage. [ABSTRACT FROM AUTHOR]

The impact of the inclusion of nickel-coated multiwalled carbon nanotube (Ni-MWCNT) filler in poly(vinylidene fluoride) (PVDF) matrix is reported in the present work. The fabricated flexible composite systems are characterized to study the behavioral changes in optical, electrical, dielectric, and magneto-dielectric aspects. The optical band gap and activation enthalpy have been effectively tuned by adding Ni-MWCNT filler. The optical energy band gap of the composite is significantly reduced with the inclusion of Ni-MWCNTs. The composite films possess enhanced dielectric permittivity and less dielectric loss than pristine PVDF film. At room temperature and 10 kHz frequency, the dielectric permittivity of Ni-MWCNT-PVDF is 20, but for pristine PVDF, it is 6. Due to the incorporation of Ni-coated MWCNT in ferroelectric PVDF, the higher magneto-dielectric coupling is achieved, which facilitates Ni-MWCNT-PVDF film as a promising material. [ABSTRACT FROM AUTHOR]

Neodymium doped Bismuth Ferrite (Nd-BFO) samples, synthesized using solid-state reaction route are subjected to various structural and dielectric characterization to investigate the influence of Nd3+ ions in modifying bismuth ferrite multiferroic properties. Structural characterizations including XRD, FESEM, FTIR, and Raman characterization have shown that higher amount of dopant concentration has caused disruption in the structural ordering. Dielectric studies such as dielectric constant, loss, measured using an LCR meter with respect to the temperature and frequency variations are analyzed in this paper. Further electrical characterization such as impedance analysis is also presented. All these results broadly indicate the tunable electrical nature of these samples at different temperatures and frequencies, with doping, which is a correlation to their structural and morphological ordering and low concentration doped Nd-BFOs only possess the potential for applications. [ABSTRACT FROM AUTHOR]

A slow evaporation procedure has been used to grow semi-organic single crystals of (LPLS) l-phenylalanine (C9H11NO2) lithium sulphate (Li2SO4). Researchers examined the various characterizations of LPLS using single-crystal XRD, FT-IR, FT-Raman, optical absorbance, transmittance, dielectrics, laser damage threshold, microhardness, photoluminescence, and NLO. Based on the X-ray diffraction experiment, it was discovered that the grown crystal exhibits a non-centrosymmetry and lattice parameters are a = 5.49 Å, b = 4.89 Å, and c = 8.20 Å and α = γ = 90° and β = 107.32° which leads to monoclinic system. UV–Visible–NIR spectra have a split absorbance curve, which is useful in the application of bandpass filters. Molecular vibration modes are determined by Infrared and Raman spectra. In the photoluminescence spectrum, the crystal emits violet and blue light. Different mechanical properties were analysed by the Vickers microhardness test. The material's dielectric characteristics have been explored. A sample with a low dielectric loss and a low dielectric constant at high frequencies suggests that it has excellent optical properties. SEM analysis was also performed on the LPLS crystal, revealing its surface morphology. To determine the chemical composition of crystals, energy-dispersive X-ray methods are used. Analysing the added dopants confirmed their presence of carbon, oxygen, and sulphate. Using a 532 nm Nd:YAG laser, the laser damage threshold was measured under single-shot mode. The Kurtz and Perry powder technique has been proven to have the NLO property. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) nanoparticles were prepared by the sol–gel process followed by the hydrothermal method. The as-prepared PZT showed Pb(Zr0.52Ti0.48)O3 phase which was successfully incorporated into a polyvinylidene fluoride (PVDF) polymer matrix by a simple solvent casting method. The X-ray diffraction and field emission scanning electron microscopy (FESEM) results showed phase purity and formation of PZT nanoparticles composited along with α and β-phase PVDF polymer. The dielectric properties of PZT-PVDF nano-composites were evaluated in detail concerning different frequencies and it was observed that the dielectric constant and dielectric loss tangent increased with the PZT content. Mixing a moderate amount (0.5 wt%) of PZT into the PVDF matrix not only enhances the dielectric constant of the matrix but also encourages the transformation of the PVDF crystal from α-phase into β-phase. These effects can improve the dielectric constant, conductivity, and dielectric loss with good dielectric stability. Room temperature dielectric measurement of 0.5PZT-PVDF composites at 30 kHz gives 10–11 times higher electrical conductivity compared to neat PVDF. Besides, it is found that dielectric permittivity values at the lower frequency are affected by space charges while in the higher frequencies the influence of relaxation effect in the materials was observed. It was realized that 0.5PZT-PVDF polymer matrix can withstand optimum temperature and the DSC thermogram exhibited good endothermic peak. Our experimental results reveal that the dielectric parameters like real, imaginary modulus and dielectric loss have a strong frequency reliance. [ABSTRACT FROM AUTHOR]

The effects of Ho doping on the microstructure, composition, vacancy defects, and magnetic properties of Gd1 − xHoxMnO3 (GHMO, x = 0.00-0.20) ceramics synthesized using the solid-state reaction method were investigated. The results revealed that the orthorhombic perovskite structure was maintained in all GHMO ceramics, while the addition of Ho ions induced lattice deformation. Ho doping displayed the function of decreasing the dielectric loss and improving the dielectric constant frequency stability. The positron annihilation lifetime spectroscopy demonstrated that when Ho content increased, the vacancy concentration initially increased and subsequently decreased. The magnetic properties measurements showed that Ho doping had a significant impact on the long-range order of Gd moments, magnetic transition temperature, and magnetization. The correlation study of structure and properties shows that the development of magnetic characteristics was strongly related to the vacancy concentration in GHMO samples. [ABSTRACT FROM AUTHOR]

As one of the main crystalline phases of A6 tape (Ferro Corp.), CaSiO3 is a promising candidate with excellent microwave dielectric traits, including a low dielectric constant and a low dielectric loss. The optimum sintering temperature of CaSiO3 ceramic can be reduced from 1250 to 925 °C with a high Q×f value after adding LiF additive. Therefore, the phase constitutions, microstructure, low-temperature sintering behaviors, and microwave dielectric traits of CaSiO3 ceramics doped with 0.5 ~ 3 wt% LiF were investigated in detail. In particular, the outstanding microwave dielectric traits (εr = 6.3, Q×f = 32,435 GHz, τf = − 28.51 ppm/°C) achieved in the CaSiO3 ceramics with 1 wt% LiF are compatible with silver when sintering at 875 °C, showing great potential for the application of low-temperature co-fired ceramic (LTCC) technology. [ABSTRACT FROM AUTHOR]

Through the avenue of adjusting the thermal properties of BaO–MgO–Al2O3–SiO2 (BMAS) glass-ceramic by changing the MgO/BaO ratio, a BMAS glass-ceramic with the MgO/BaO ratio of 1:2 has been obtained, which shows satisfactory softening and crystalline behavior. Then, this BMAS glass-ceramic is used to lower the sintering temperature of Al2O3 ceramic. After systematic research on the sintering and physical properties of BMAS /Al2O3 composite with different glass-ceramic content, we find that when the content of BMAS glass-ceramic is 50%, the composite presents adorable comprehensive properties: dielectric constant of 5.40 @ ~10 GHz, dielectric loss of 1.91 × 10− 3 @ ~10 GHz and bending strength of 143 MPa, meeting the requirement of LTCC substrate material for microwave application. [ABSTRACT FROM AUTHOR]

The CuO nanoparticles prepared by high yielding, eco-friendly, non-hazardous, cost-effective, and simple Exploding Wire Technique and subsequently subjected to annealing at 900 °C for 7 h were analyzed through a series of characterization techniques. X-ray diffraction data analysis was performed to determine the crystallite phase and size of CuO at 900 °C. The direct current (DC) electrical attributes of synthesized nanoparticles were measured using two-probe system in the span of 300–512 K. The activation drive for hopping of charge carriers, drift mobility, and carrier density were evaluated through DC investigation. The traits of dielectric responses like dielectric constant or relative permittivity (ε′), tangent loss (tan δ), dielectric loss (ε″) and alternating current (AC) conductivity (σAC) were investigated at different thermal states in the frequency span of 10–105 Hz. The surge in AC conductivity with frequency, as detected in the present case, represents typical behavior of spinel ferrite. The alteration in relative permittivity with frequency could be acceptably explicated through two-layer model formulated on space charge polarization. The dielectric properties at various frequencies were investigated in the temperature span of 300–500 K. The reduction in DC resistivity along with the surge in AC conductivity with temperature acknowledged the semiconducting essence of synthesized CuO nanoparticles. [ABSTRACT FROM AUTHOR]

Conductive carbon black-coated BaZn2Fe16O27 composite absorbent was successfully prepared by a simple mechanical blending method. The phase composition, microstructure, magnetic and electromagnetic properties of the composite powder were analysed and characterized by XRD, SEM, VSM and network analyzer, and the reflection loss of the composite powder was simulated by software YRcomputor. Morphological analysis showed the micron-sized carbon black was uniformly coated on the surface of hexagonal flake ferrite. The sample has a dual-loss mechanism of dielectric and magnetic loss. The combination of carbon black and W-type BaZn2Fe16O27 effectively improves the impedance-matching condition and broadens the wave absorption band. The ferrite/carbon black composite (the ferrite/carbon black ratio is 100:4) shows microwave absorption with a maximum reflection loss of −23 dB with a thickness of 4 mm. It exhibits an effective absorption bandwidth (EAB) of 8.6 GHz with a thickness of 2.5 mm. Noting that, by adjusting the carbon black content and the thickness (2–4 mm), reflection loss (RL) lower than −10 dB can be achieved in the range of 8–16 GHz, which basically covers the X-band and Ku-band. [ABSTRACT FROM AUTHOR]

Employing the slow evaporation technique with millipore water as a solvent a single crystal of pure potassium dihydrogen phosphate crystal (KH2PO4) and KH2PO4 doped with magnesium chloride crystal (MCKH2PO4) were grown at room temperature. The powder X-ray diffraction studies show peaks of the MCKH2PO4 crystal coordinates well with the pure KH2PO4 with minute alterations to the strength of the diverged peaks. Investigations from single-crystal XRD show that KH2PO4 and MCKH2PO4 belong to tetragonal crystal system and I-42d space group, and their lattice parameters are also assessed. FTIR spectral analysis exhibits the functional group analysis of KH2PO4 and MCKH2PO4. The optical data such as transmittance and lower cutoff wavelength was investigated using UV–Vis-NIR spectral studies, and it is found to be 381 nm for pure KH2PO4 and 383 nm for MCKH2PO4. From Tau's plot, optical band gap is calculated to be 2.83 and 2.95 eV for KH2PO4 and MCKH2PO4, respectively. The SHG efficiency of KH2PO4 and MCKH2PO4 is measured using Kurtz-Perry powder technique. The calculated efficiency of MCKH2PO4 is found to be 1.02 times more than that of pure KH2PO4. At higher frequencies and temperatures, grown crystals have lower permittivity and dielectric loss tangent. The mechanical behavior of KH2PO4 and MCKH2PO4 is estimated using Vickers microhardness studies. Thermal analysis and decomposition temperature are determined by TGA and DTA studies. Third-order susceptibility is determined by the Z-scan technique. [ABSTRACT FROM AUTHOR]

Hard–soft CoFe2O4/Ni0.3CuxZnyFe2O4 (x, y ≤ 0.5) spinel ferrite nanofibers (H/S CFO/CuZnFO SFNFs) were synthesized via electro-spin. The main aim of this study is to investigate effect of co-substitution of transition metals of Cu and Zn on the dielectric features of H/S CFO/NiFO SFNFs. The microstructure and morphology of all products were studied by XRD, SEM along with EDX, TEM and HR-TEM. The dielectric features of all products were evaluated as a function of frequency, F (1 MHz–3 GHz), and temperature, T (20–120 °C). The T-dependent AC and DC conductivity of all products improved with T, in agreement with the semiconductor behavior. While AC conductivity revealed two regions as F-dependent and F-independent, DC conductivities exhibited Arrhenius-type behavior above and below the transition T. Thermally stimulated charge transfer model produced activation energies before and after transition T ranging between Ea = 78 and 297 meV, which is consistent with AC and DC conductivities. The dielectric loss, dielectric constant and dielectric loss tangent of all nanofibers decreased with the increase in F at all T. The Cole–Cole plots were used to analyze the effect of grain and grain boundary on conduction mechanism, and they displayed mainly only one incomplete semicircle signifying non-Debye behavior and domination of grain boundaries to the conduction mechanism. The dielectric parameters of all samples vary significantly with compositional ratio. The dielectric behaviors of H/S CFO/CuZnFO SFNFs are correlated with the conduction mechanisms based on grain-to-grain boundaries, clarified by Koop's model. [ABSTRACT FROM AUTHOR]

The L-Alanine (LA) crystals are grown using slow evaporation method with the cell dimensions as a = 5.7780(5) Å; b = 6.0284(6) Å; c = 12.3237(12) Å. The dielectric constant and dielectric loss of the LA micro crystals are having higher value at low frequencies and lower value at higher value of frequencies; Z Scan methodology envisages the nonlinear nature of LA specimen; the third order non linear susceptibility is 1.90 × 10–6 esu; 8.89 × 10–6 esu for macro, micro scalings and having phase matching proviso for micro-LA of 38.2 mV. The doubling esteem of Op-amp for the input frequency is properly analyzed for the macro; micro level coated ones and is of 2.07 times that of the input esteem, 2.12 times that of the input esteem. The values of 2.9876, 3.4343 and 3.8912 microns for macro, thin-film and micro level influx of LA. Voltage regulation enhancing the use in boosting and bucking materials with LA micro-ones. The LA micro crystalline material is of 10 μm specification tells that the specimen has no flaws; the stereographic consequence of LA crystal with hkl max and Laue's effect of LA crystal with 2717 reflections and angle portrayal for hkl1 as (100) and hkl2 as (111) is 46.85°; the computational approach for LA for Halosian impactness for projection in a giant scale. The weak interaction profile of 50% effect by VanderWaal's is properly portrayed; the nano-tube of 22 nm of 3 × 3 value of n, m for peptide bond of Arginine triplets case for 5 × 5 × 5 holder of LA are pronounced with the 4 × 4 × 4 super cell impacting of LA material. The projected data of LA structure for (101) orientation and for (111) orientation with the cloned cluster effect of LA crystals for thermal imaging; cluster effectiveness; to be employed in imaging and display circuits also analyzed for micro-photonic utilities with 3.98 eV. [ABSTRACT FROM AUTHOR]

Tetra-doping by (Mn, Fe, Co, Ni) ions strongly boosted the room temperature dielectric constant and the ferromagnetic-superparamagnetic characteristics of monoclinic CuO structure. In this study, undoped CuO, Cu0.98Mn0.005Fe0.005Co0.005Ni0.005O, Cu0.96Mn0.01Fe0.01Co0.01Ni0.01O and Cu0.94Mn0.015Fe0.015Co0.015Ni0.015O nanocompositions were synthesized through coprecipitation technique. The crystal structure analysis verified that all samples have a pure single phase, corresponding to monoclinic CuO structure. The substitution of Cu2+-sites into CuO lattice by Mn2+, Fe2+/3+, Co2+ and Ni2+ ions has been deduced from the expansions of lattice constant, shifts of XRD diffraction peaks and band gap energy alteration. The additions of (Mn, Fe, Co, Ni) ions lead to the formation of homogenous distributed very fine spherical nanoparticles, especially at large concentrations of dopants (Cu0.94Mn0.015Fe0.015Co0.015Ni0.015O sample). The tetra-doping by (Mn, Fe, Co, Ni) ions reduced the intensity of the diffuse reflectance alongside red shifted the absorption edge and the band gap energy of monoclinic CuO structure. Cu0.98Mn0.005Fe0.005Co0.005Ni0.005O exhibits a high relative permittivity value of 6096 at low frequency of 42 Hz with small dielectric loss tangent (tan δ) compared to pure one. The tetra-doping by (Mn, Fe, Co, Ni) dopants induced excellent intrinsic ferromagnetic and superparamagnetic hysteresis loops into monoclinic CuO structure with full saturation loops shape and variable coercivity values. [ABSTRACT FROM AUTHOR]

In this work, the structural, microstructural, dielectric and piezoelectric properties of sol–gel processed rare earth-doped PbTiO3 (PT) samples with the compositions Pb0.86La0.14HoxTi1−xO3 (x = 0, 0.5, 1.5, 0.2 and 2.5%) (PLHTx), calcined at 700 °C for 2 h and sintered at 1100 °C for 4 h, were studied. X-ray diffraction and Raman spectroscopy results showed that the samples exhibited the pseudo-cubic phase (P4mm), without any secondary phase, and that Ho3+ ions can occupy both Pb and Ti sites in the Pb0.86La0.14HoxTi1−xO3 matrix. Scanning electron microscopy (SEM) analysis showed that the average grain size in the samples was 366–416 nm. Dielectric measurements revealed that holmium substitution has no effect on the temperature of the permittivity maximum at the ferroelectric to paraelectric transition (FPT). Moreover, relatively high values of the dielectric permittivity and low values of the dielectric losses were obtained under holmium doping, and the value of the maximum of the dielectric constant (εr max) at the FPT showed a particular behavior. The resonance phenomenon was observed in the permittivity dependence on frequency in the frequency range 100 Hz–2 MHz, allowing the extraction of some piezoelectric parameters such as the electromechanical coupling factor, kp, that increased with the increase in the holmium content. [ABSTRACT FROM AUTHOR]

Advanced microwave-absorbing materials are technologically significant with extensive utilization of electronic communication equipment. Due to its good chemical stability, high-specific saturation magnetization, and high snoek's limit, Fe4N has attracted widespread attention as a microwave-absorbing material. In this work, we transferred the spherical Fe into spherical Fe4N by the gas-nitriding process. The obtained spherical Fe4N exhibit an enhanced microwave absorption ability than spherical Fe. When the matching thickness is only 1.5 mm, the minimum reflection loss (RLmin) runs up to − 22.3 dB. And the effective absorption bandwidth achieves 4.5 GHz when the matching thickness rises to 2 mm. Through the characterization of crystal structure, microscopic morphology, magnetic properties, and absorbing properties, we explored the mechanisms for improved microwave absorption performance in spherical Fe4N. Improved dielectric loss mechanisms, such as interface polarization and conductive loss, were discovered for spherical Fe4N. The microwave absorption performance also heavily relies on the magnetic loss mechanisms of eddy current loss, natural resonance, exchange resonance, and hysteresis loss. Meanwhile, the formation of Fe4N in SFN improves attenuation constant and optimizes impedance matching which take advantages of the synergy of dielectric loss and magnetic loss. Additionally, the 1/4λ interference cancellation theory's destructive interference occurs in microwave absorption process of spherical Fe4N. This research not only provides a new high-performance microwave absorber but also supplies experience for the preparation of Fe4N-based composite microwave absorbers. [ABSTRACT FROM AUTHOR]

The inorganic crystalline specimen of Tri caesium di-molybdate (VI) bromide - TCDMB is grown and the lattice parameters portrays the hexagonal type of TCDMB system with a = b = 6.3996 (5) Å and c = 16.4867(15) Å and analyzed for gamma irradiated macro ones and confirmed the presence and also for micro-TCDMB confirmed the scale with SEM of 50 μm also studied for dielectric constant and dielectric loss and found that both are decreasing with increase in log f values and high value of dielectrics represents the projected capacitor use and mainly super-capacitor as the specimen is inorganic by nature. TCDMB are further preceded for the Platon plot and CHNSO theoretical a representation deliberates the confirmation of the structure and % of elements in the TCDMB inorganic crystalline specimen. The electronic utility by means of influx data and the macro, micro influx of 2.7865 and 2.8165 microns and nano influx is 3.2969 micron for TCDMB crystals are specified for opto-electronic filters and the film coating influx of 2.9878 microns as middle value amid the macro and the nano inference. The doubling of the frequency by BY127 diode and BAT62 diode and TCDMB macro encrusted diodes; output value for the macro encrusted diodes for use in enhancing circuits. The hardness profile of TCDMB is of Reverse ISE effect and mechano efficiency of 36.5% also represented for spectral and photonic utilities by UV, fluorescence data with distinct macro, micro and gamma irradiated ones and specified the versatility by value and by utility of them for violet and indigo-bluish fluorescence. [ABSTRACT FROM AUTHOR]

The optically clear single crystals of pure and safranin dye-doped (0.01 and 0.05 mol percent) triglycine acetate were produced using the slow evaporation solution approach (TGA). Powder X-ray diffraction was used to analyze the crystallinity and different planes of the material. FTIR and Raman spectroscopy were used to confirm the existence of various functional groups and dopant inclusion in the crystals that were grown. In the UV-Vis-NIR absorption spectra, four distinct absorption bands were found after safranin dye was introduced to the TGA matrix. The safranin dye-doped TGA crystals did not lose weight up to 225 °C (0.01 mol percent) and 227 °C (0.05 mol percent), respectively. Safranin dye staining in TGA material resulted on an increase in dielectric constant and a decrease in dielectric loss. The doped crystals' improved optical qualities and thermal stability show that they are suitable for technological applications. [ABSTRACT FROM AUTHOR]

The barium titanate ceramics (BaTiO3) are the key components of the multilayer ceramics capacitors (MLCCs). For a long time, huge efforts have been devoted to achieving the fine-grained BaTiO3 ceramics to satisfy the miniaturization and high integration of electronic devices. However, the controllable grain size which is particularly crucial to regulate the BDS, permittivity and dielectric loss has gained little attention. With the target of achieving the micro–nano-BaTiO3 ceramics with different sizes controllably, we prepare them via a self-assembly sintering method. By giving the size of the BaTiO3 powders and the combination way, the binary particle size self-assembly sintering method can controllably synthesize the ceramics with different grain sizes. When the powders combination is 400 nm + 80 nm, the relative density of the ceramics with grain size 450 nm is 92%. As the powders combination is 500 nm + 80 nm, the relative density of the ceramic with grain size 540 nm is 91%. When the ternary and quaternary particle size self-assembly sintering method is used to synthesize the ceramics, the relative density of the ceramics can be increased, but the controllability of the grain size has been reduced. The relative densities of the ceramics obtained by the ternary and quaternary systems were 95% and 96%, respectively, and the grain sizes of the ceramics were 610 nm and 676 nm, respectively. Therefore, the use of binary particle size self-assembly sintering method is beneficial to synthesize the micro–nano-BaTiO3 ceramics controllably. [ABSTRACT FROM AUTHOR]

This work aims at investigating the influence of Co2+ and Mn2+ metal ions on the properties of l-ornithine monohydrochloride (LOMHC) single crystals, which were grown by slow evaporation technique. The crystals were examined by different analytical tools. The structural study revealed that crystals are belonged to a monoclinic system with noncentrosymmetric space group P21. The presence of dopants in the LOMHC was confirmed by PXRD and EDAX analysis. The doped crystals showed a wide transmission window and have superior transmittance to that of pure crystal. Also, the energy gap is increased. From TG-DSC investigations, the thermal stability of LOMHC crystal did not change considerably upon doping. The behaviour of dielectric constant and dielectric loss as a function of frequency for pure and doped crystals were studied. The integration of metal ions makes LOMHC into a ferromagnetic material. Among the dopants, Mn2+ doped LOMHC showed higher second-harmonic generation (SHG) efficiency. [ABSTRACT FROM AUTHOR]

Lanthanum cuprate (La2CuO4) perovskite-type nanoparticles were synthesized by facile microwave-assisted combustion (2.45 GHz/900 W) for 15 min and calcinated at 500, 700, 900, and 1000 °C for 2 h. The effect of calcination temperature on the structural, optical, magnetic, and dielectric properties was investigated. The XRD studies confirmed that the perovskite nanoparticles with different temperatures from 500 to 900 °C possess a single-phase orthorhombic crystal structure of La2CuO4. In contrast, when the temperature increased to 1000 °C, the structure changed from orthorhombic to tetragonal. The average crystallite size of the orthorhombic phase is in the range of 37–47 nm. The presence of tensile strain in La2CuO4 was determined from Williamson–Hall (W–H) analysis. The appearance of FT-IR bands at approximately 634 and 970 cm−1 was correlated to the La–O and Cu–O stretching modes of the orthorhombic La2CuO4 phase. UV–Vis spectroscopy indicates that calcination temperature over the 500–1000 °C temperature range causes the band gap to decrease from 2.15 to 1.63 eV. The lanthanum cuprate system showed the formation of nanosized crystallized grains with pores and pore walls due to fused grains. The Magnetization–Field (M–H) hysteresis curves revealed the appearance of ferromagnetic behavior at room temperature. The dielectric properties of the fabricated La2CuO4 perovskite nanoparticles were evaluated at different temperatures and frequency-dependent dielectric constant, dielectric loss and AC conductivity, respectively. [ABSTRACT FROM AUTHOR]

A series of Ba0.85Ca0.15Zr0.1Ti0.9O3 (referred to as BCZT) ceramics were fabricated by the sol–gel method with different aging temperatures. The structure, dielectric property, and the energy storage property were researched. Compared with the BCZT synthesized with the traditional solid-state reaction method, the samples prepared by the sol–gel method have obvious advantages in various performances. And a strong influence of aging temperature on the BCZT ceramics was observed. The suitable aging temperature can broaden the dielectric peak and decrease the Curie temperature. In addition, the optimal BCZT sample with the aging temperature of 60 °C exists a high permittivity (εr ~ 3141) and a low dielectric loss (tanδ ~ 0.012) at the frequency of 102 Hz. Moreover, the coercive field and remnant polarization of the BCZT were greatly decreased, contributing to slim hysteresis loops. Notably, the thinner P-E loop contributes a high energy storage efficiency (76.6%) at 40 kV/cm electric field which is much higher than the BCZT synthesized by the traditional solid-state reaction method. All measurements indicate the effect of aging temperature on ceramic properties is related to the grain size and the degree of diffusion. [ABSTRACT FROM AUTHOR]

A study on Ba2Ti9O20 and SiO2 ceramic powder-filled polybutadiene (PB) composite substrates was conducted in this paper. The total content of ceramic fillers was a fixed value of 85 wt.% and the SiO2 content varied from 5 to 25 wt.%. The analyses of FTIR, XPS, TEM, Contact Angle testing, and SEM were performed to study the surface characteristics of Vinyltrimethoxysilane (A171)-modified Ba2Ti9O20. The microstructure of composite substrates displayed that Ba2Ti9O20 and SiO2 ceramic fillers distributed in PB homogeneously with a small amount of SiO2 addition. However, SiO2 filler particles agglomerated and poorly dispersed in composites with 25 wt.% SiO2 loading. Furthermore, the effects of SiO2 filler loading on density, porosity, dielectric properties, and mechanical properties of composites were investigated in detail. Last, the composites exhibited medium dielectric constant (ε r = 7.32) , low dielectric loss (tan δ = 0.002), near-zero temperature coefficient of dielectric constant ( τ ε = - 8.07 ppm / ∘ C ) at a high frequency of 10 GHz, relatively low porosity (1.36%), and acceptable bending strength (75.26 MPa) at 65 wt.% Ba2Ti9O20 and 20 wt.% SiO2 fillers loading. [ABSTRACT FROM AUTHOR]

Impregnation resin is one of the most commonly used insulation materials for electrical equipment and it is a key factor that can determine the volume, quality and service life of electrical equipment. From the perspective of the excellent electrical performance and high heat-resistant temperature of bismaleimide resin, BMI resin is a good choice as an impregnating paint for motor. However, the poor toughness of BMI resin and its high susceptibility to brittle fracture limit the application of BMI resin to a great extent. In this paper, a novel hyperbranched polyimide (HBPI) is designed to improve the toughness and electrical properties of BMI resins. Along with the addition of HBPI, the free volume within the system increases accordingly, which contributes to the improvement of the mechanical and electrical properties of BMI resins. Due to the detection of 13C-NMR (13C Nuclear Magnetic Resonance Spectroscopy), 1H-NMR (1H Nuclear Magnetic Resonance Spectroscopy) and FT-IR (Fourier Transform Infrared Spectroscopy), the synthesized HBPI has an excellent branched structure and the mechanical properties of the toughened BMI resin is significantly improved. The flexural strength achieves a maximum value of 82 MPa when HBPI increases to 30 wt.%, Young's modulus reaches a maximum value of 3.76 GPa when HBPI increases to 30 wt.%, and impact strength attains a maximum value of 25.7 kJ/mm2 when HBPI increases to 20 wt.%. When HBPI increases to 40 wt.%, the dielectric constant reaches a minimum value of 2.90. When the addition amount of HBPI is 40 wt.%, the dielectric loss reaches the minimum value of 0.00215. When the addition amount of HBPI is 20 wt.%, the volume resistivity achieves the maximum value of 4.12 × 1015 Ω. When HBPI is increased to 40 wt.%, the breakdown field strength reaches a maximum of 36.8 kV/mm. It is worth noticing that HBPI is available in BMI resin significantly to improve its electrical performance. As the experimental data shows, the mechanical properties and insulation properties of BMI resin strengthened by HBPI satisfy the requirements of insulation impregnating paint for motor. [ABSTRACT FROM AUTHOR]

Precious water resources are under threat by pollution due to toxic organic dyes from industries. As a solution for water pollution, we have developed a multifunctional photocatalyst that will effectively degrade the toxic pollutants in the water bodies. We synthesized aluminium-doped Co–Mn ferrites as a photocatalyst via citrate-gel method and investigated the degradation of toxic pollutants of water such as Rhodamine B (RhB), Crystal violet (CV) under visible light for their potential application in wastewater treatment. One of the compositions of the catalyst Co0.75Mn0.25AlFeO4 has shown effective photocatalytic performance in degrading RhB and CV with ⋅OH radical and holes (h+) as active species responsible for degradation. The dielectric and impedance properties of Co–Mn nanoferrites and the influence of Al were also studied from room temperature (RT) to 350 °C. Dielectric studies revealed a normal dielectric behaviour of the samples with regard to frequency at various temperatures as evident by Koop's theory and Maxwell–Wagner bilayer model. A decline in the dielectric parameters such as dielectric loss and dielectric constant was observed with an increase in Aluminium doping. Influence of frequency and temperature on dielectric parameters and impedance was studied. Area under the curve of Nyquist plots decreased with rise in temperature that represent the tendency of ferrite samples to show better conductivity. Observed low dielectric loss by Al doping in Co–Mn ferrites makes these materials appropriate for microwave devices at high frequency with low eddy current losses. [ABSTRACT FROM AUTHOR]

The role of co-doping with Ba and Sm in Bi and Fe sites of BiFeO3 (BFO), respectively, on the structural and multiferroic properties has been studied in this investigation. Multiferroic ceramics Bi0.85Ba0.15Fe1−xSmxO3 (BBFSO) with x = 0, 0.02, 0.05, and 0.07 have been synthesized by using the standard solid-state reaction method. The Structural depiction and surface morphology are accomplished by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM), respectively. Analysis of the XRD pattern reveals that the structural phase is found pseudo-cubic with the substitution of Ba and Sm for all the samples. Microstructural investigation shows that the samples possess fine crystalline structure and the estimated grain size decreases with the increase in Sm content. The electromagnetic properties such as complex initial permeability, relative quality factor, dielectric constant, dielectric loss, and ac conductivity have been measured by Wayne Kerr Impedance Analyzer. It is found that co-doped samples have improved dielectric property. The sample having 2% Sm exhibits the highest dielectric constant and lowest loss in the dispersive region. Enhanced electric polarization is found for co-doped samples, which might be due to the reduction in leakage current. From impedance spectroscopy analysis, it is observed that only grain boundary is responsible for the conduction process and the electric modulus confirms the existence of electronic relaxation. The real part of initial permeability and relative quality factor increase significantly with Sm doping. The magnetic hysteresis loops confirm that Sm doping notably increases the coercivity of the Bi0.85Ba0.15FeO3 ceramics. The coexistence of ferroelectricity and ferromagnetism in BBFSO as is evident from the P–E and M–H loops can be used for fabricating magnetoelectric devices. [ABSTRACT FROM AUTHOR]

Al-doped BaZr0.2Ti0.8O3 (BZT20) ceramics were prepared by solid-state sintering, and the relaxation degree of phase transition was tailored effectively. The microstructure, dielectric properties, ferroelectric properties, and electrocaloric (EC) performance of Al2O3-doped BZT20 ceramics were studied, respectively. The results show that Al2O3 doping induces changes in Curie temperature and dielectric properties. When the additive amount of Al2O3 is 1.25 at.%, the Curie temperature drops to around room temperature (RT), and the dielectric loss is lower than that of pure BZT20 ceramics. The diffusion constant γ reaches a minimum value of 1.57 when the Al2O3 content is 1.25 at.%, indicating that a relatively large latent heat would be gathered while there is a phase transition. As a result, an enhanced EC response of ∆Tmax = 0.293 K near RT is obtained when the Al2O3 content is 1.25 at.%, which is 1.6 times that of pure BZT20. It is also impressive that a wide working temperature range can be obtained, that is, Tspan = 73 K for BZT20 ceramics with 1 at.% of Al3+ ionic content. [ABSTRACT FROM AUTHOR]

BaO–Al2O3–SiO2–B2O3 (BASB) glass-ceramic designed to replace the glass additive in traditional glass + ceramic composite system as LTCC material has been investigated. The influence of additive amount of glass former B2O3, network modifier BaO and network intermediate Al2O3 on the thermodynamic properties of BASB glass-ceramics is studied. The results show that the increase of both B2O3 and BaO can lower the softening and crystallization temperatures of the glass-ceramic. At the same time, the increase of BaO content leads to the reduction in sintering shrinkage rate. The addition of Al2O3 can decrease the crystallization temperature, but the softening temperature will exhibit a complicated variation of decreasing at first and then rising. Based on the aforementioned results, an optimum BASB glass-ceramic consisting of 13 mol% B2O3, 24 mol% BaO, 12 mol% Al2O3, 50 mol% SiO2, 1 mol% ZrO2 and 1 mol% Li2O is produced, with the softening temperature of 650 °C, main crystalline phase of BaAl2Si2O8 after being sintered at 850 °C and the crystallization activation energy of 292.25 kJ/mol. The received glass-ceramic is then employed as sintering aid to fabricate low-temperature-sintered BASB glass-ceramic + Al2O3 ceramic composite. The 55 wt.% BASB + 45 wt.% Al2O3 composite sintered at 850 °C shows attractive comprehensive properties with a density of 2.79 g/cm3, dielectric constant of 5.88@10 GHz and dielectric loss of 1.54 × 10–3@10 GHz, which makes it a good candidate for microwave LTCC substrate application. [ABSTRACT FROM AUTHOR]

In this work, Al2O3–CeMgAl11O19 composites were sintered at 1530 °C for 3 h with the wet nitrogen–hydrogen atmosphere in the tunnel kiln for HTCC application. The effects of the CeMgAl11O19 content on the mechanical and dielectric properties were investigated. The results indicated that the CeMgAl11O19 platelets significantly enhanced the mechanical property and slightly reduced the grain size of Al2O3. The optimum bending strength was 450 MPa with 8 wt% CeMgAl11O19 addition. But further additions would promote the abnormal growth of grains and increase porosity. CeMgAl11O19 exhibited insignificant effects on the dielectric properties of composite ceramics, with all samples having dielectric constants in the range of 9–10 and acceptable dielectric losses. For the composite ceramics with 8 wt% CeMgAl11O19, a strong metal–ceramic combination was obtained with metallization adhesion strength greater than 44.5 N/mm2. [ABSTRACT FROM AUTHOR]