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This study investigated the influence of the ZnO morphology on the energy storage capacity of symmetric supercapacitor devices, focusing on the defect centers present in the materials due to morpho-structural differences. Thus, ZnOs with five different morphologies were synthesized with varying methods in which the nanoparticles have the form of flowers, bullets, pyramids, hexagons, and rods. All materials were thoroughly characterized by scanning/transmission electron microscopy, X-ray diffraction, and spectroscopic techniques like photoluminescence, UV–Vis, Raman, and electron paramagnetic resonance spectroscopy. Subsequently, the ZnO-based materials were assembled in symmetric supercapacitor devices to test their energy storage capabilities. The ZnO with nanorod and hexagonal morphologies showed the best specific capacity (180 and 142 F/g), energy density (25 and 19 Wh/kg), and power density (211 and 252 kW/kg) values. The importance of the defect centers in the materials was highlighted, where the ratio between the Zn and O vacancies, evidenced by EPR spectroscopy, plays a crucial role in the ZnO materials' energy storage capacity. The Raman results support the proposed model, which underlines the importance of oxygen vacancies. In contrast, BET measurements show that the specific surface area of the morphologically distinct ZnO materials does not change drastically, validating the importance of the defect centers in the materials. A so-called "bottle-neck" effect is proposed to describe the relation between the paramagnetic vacancies and the electric properties of the materials. [Display omitted] [ABSTRACT FROM AUTHOR]

The ability to control the optical properties of a material with an electric field has led to optical memory devices, communication systems, optical signal processing, or quantum cryptography. Understanding electro-optic effects, especially in thin films, would improve the efficiency of these applications. In particular, the influence of epitaxial strains is of prime importance. In addition, the active control of these effects would be of great interest to tailor the material to the desired performance. Here, we demonstrate through first-principle calculations that the linear electro-optic response (Pockels effect) of two silicon-compatible ferroelectrics is stable with respect to bi-axial strain and that the electro-optic response can be strongly enhanced through the electrical control of the polarization. We attribute the former to the lack of optical phonon softening and a weak elasto-optic response and the latter to the externally induced softening of a phonon of symmetry A 1. Our results are readily applicable to other polar materials and show that the electro-optic effect can be efficiently engineered to meet the performance criteria of future technologies. [ABSTRACT FROM AUTHOR]

The paper deals with the finite element (FE) analysis of the temperature influence on functional parameters of the line start permanent magnet synchronous motor (LSPMSM). The two‐dimensional (2D) FE model of coupled electromagnetic and thermal phenomena in the LSPMSM was described. The non‐linearity of the magnetic circuit and the influence of temperature on the magnetic properties of permanent magnets, as well as on the electric and thermal properties of the materials, have been considered. To analyse the effect of temperature on the functional parameters of a line start permanent magnet synchronous motor, in‐house software was elaborated. The simulation results were validated by measurements of the prototype motor on a specially designed and constructed measuring test stand. The results of the research on experimental verification of temperature effects on functional parameters in the LSPMSM were presented, and the conclusions resulting therefrom have been formulated. [ABSTRACT FROM AUTHOR]

Researchers at North Carolina State University have developed a stretchable strain sensor that can detect even minor changes in strain with a greater range of motion than previous technologies. The sensor consists of a silver nanowire network embedded in an elastic polymer, and it measures strain by measuring changes in electrical resistance. The researchers have demonstrated the sensor's utility in wearable devices for monitoring motion in physical therapy and in human-machine interface devices for controlling video games. The sensor can be easily incorporated into existing wearable materials and has potential for a range of additional applications. [Extracted from the article]

We study the flexoelectric effect induced in an infinite strip of a dielectric material, due to an applied shear deformation at the upper surface, while the lower surface is fixed. The model incorporates dynamic spontaneous polarization, flexocoupling deformation, and microinertia effects to evaluate these effects combined. The variation of the Hamiltonian functional in the medium, and of the external forces yields the governing equations and the boundary conditions. There are many types of applied boundary conditions besides the initial conditions, where the initial conditions are imposed due to the dynamics of many effects in the mathematical modelling formulation. In addition to that, the boundary conditions are divided into two groups, where the first group contains mechanical boundary conditions such as traction boundary conditions and displacement boundary conditions for the classical treatment as in the theory of elasticity while for the strain gradient theory of elasticity, conditions for higher-order traction vector should be imposed and cannot be neglected. The proposed technique depends on applying Laplace’s transform to the field equations to obtain the characteristic equation, the roots of which are expressed in terms of the s;-transform parameter and other parameters related to the elastic and electric properties of the material. Those roots which produce a bounded solution are then approximated using Taylor’s expansion, then the boundary conditions are applied to complete the solution. This technique enables to obtain the solution in terms of simple analytical functions that are easily inverted from the s-domain to the time domain. This technique is applied to a simple shear deformation problem to study the dynamical flexoelectric effect in dielectric materials due to shear displacement and external electric potential. A suitable material, such as Strontium Titanate material, SrTiO3, is used for numerical simulation, and the results are analyzed, discussed, and represented graphically. [ABSTRACT FROM AUTHOR]

This work describes how to use the solution casting method to add varying amounts (0, 1, 2, 3, and 4) of Y2O3 and SrCO3 nanoparticles (NPs) to polyvinyl alcohol (PVA) composites. The optical microscopy images showed the formation of networked channels inside the polymeric matrix as electrically charged particles, which became more intense at higher nanoparticle concentrations. With the use of field emission scanning electron microscopy (FESEM), the surface of the nanocomposite was examined. The Y2O3 and SrCO3 nanoparticles were found to be consistently and equally distributed throughout the PVA polymer matrix. Fourier transformation spectroscopy (FTIR) was used to analyses the structural characteristics of the nanocomposite and gather data on molecular vibration. The polymer matrix interacted with the additional Y2O3 and SrCO3 nanoparticles, according to FTIR analysis. Physical interactions between Y2O3 and SrCO3 nanoparticles and the PVA polymer matrix have been demonstrated by the FTIR analysis. The dielectric constant and loss were found to be significant of (PVA/Y2O3/SrCO3) nanocomposite decrease with increasing of frequency while, they are increase with content ratio of Y2O3 and SrCO3 NPs. The A.C. conductivity of (PVA/Y2O3/SrCO3) nanocomposite increase with increasing of frequency and concentration of Y2O3 and SrCO3 NPs. Finally, the PVA/Y2O3/SrCO3 nanocomposites were tested for the antibacterial against both gram positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). The result obtained that the inhibition zone diameter increased with increasing Y2O3 and SrCO3 NPs. The PVA/Y2O3/SrCO3 nanocomposite exhibited antibacterial activity. [ABSTRACT FROM AUTHOR]

The study area is located in Jos South Local Government Area of Plateau State, northcentral Nigeria. Artisanal mining activity is dominant in the area with a form of sub-surface extraction of the tin through underground cavities. This research aimed at detecting subsurface cavity using 2D Electrical Resistivity Tomography (ERT) at some mining sites in the study area. Campus Omega Terra-meter was used for the survey and Wenner-Schlumberger electrode configuration was adopted with inter-electrode spacing for the various sites ranged from 2m, 5m, and 10m. Active and non-active mine sites was selected for the study and field data where interpreted using the RES2DINV software. The smoothness constrain in version formulation was adopted. In Kuru area an oval shaped high resistivity values of about 736 to 1448Om suggests an air-filled cavity and a low resistivity values of 49.1 to 33Om indicates water filled cavity while control profile shows a low resistivity values of 64.6 to 98.7Om at a depth of 31.9m as a very good aquifer, for locating a deep well. In NTA college area, three geoelectric materials namely: clay, lateritic and sandy clay were observed. The resistivity value of about 77.7Om which was lower than ressistivity value of the host country rocks of 236Om suggests a water filled cavity and lower resistivity value of 97.2Om at Profile 2 attested to water filled cavity while resistivity value of above 822Om may indicate extension of air-filled cavity at Control Profile. A high resistivity value of 1483Om characterised the top soil at a depth of about 7m at control profile in Dura-Du area and A low resistivity value 80.1 to 122 Om at depth of about 13m to 15.9m indicates fresh water. The 2D ERT geophysical method has been used succefully to identify air-filled, waterfilled and fresh water zones in the study area.. [ABSTRACT FROM AUTHOR]

Permanent magnet-assisted synchronous machines and double-rotor single-stator axial flux machines are relevant new topology traction machines for electrified vehicles, thanks to their limited critical rare-earth magnet consumption for delivering the required torque, power density, and power levels. This study details the impact of the soft ferromagnetic materials in these two machine types, in a parametric approach, with a wide range of electric and magnetic material properties. Furthermore, the machines have been studied at their operating temperatures, with measured material data (resistivity, permeability, remanence, coercivity, iron losses, thermal diffusivity, thermal conductivity, specific heat capacity) at such temperatures. The impact of the soft ferromagnetic property choice decreases from room temperature to operating temperature. The detailed impact of magnetization and loss changes in the soft magnetic material with temperature, as well as its thermal properties that govern heat exchanges, have been calculated in a loosely coupled electromagnetic–thermal approach. The results bring into perspective the relative impact of each of the active materials in the electrical machines, as a function of the temperature range of the working points of the machines. [ABSTRACT FROM AUTHOR]

Spray Pyrolysis (SP), a low-cost chemical procedure was employed to deposit ZnO thin films under optimum conditions at 350 °C using a predetermined precursor concentration of 0.1 M. This study investigates how post-air annealing affects the structural, compositional, morphological, optical, and electrical properties of ZnO thin films. The deposited films were heated by air at 400, 450 and 500 °C for 1 h. X-ray diffraction, scanning electron microscope, x-ray dispersive spectroscopy, Raman spectroscopy, Fourier Transform Infrared Spectroscopy, optical spectroscopy, and Hall effect studies were conducted to investigate how post-air annealing alters the properties of the as-deposited film. XRD measurements show that annealing resulted in the growth of polycrystalline hexagonal wurtzite without the formation of any other phases in ZnO films. When heated to 500 °C, the estimated crystallite size of the as-deposited film increased from 6.22 nm to 6.57 nm. The SEM show the creation of compact and tightly packed films, as well as the visible network of large grains during annealing. Raman and FTIR studies have validated the chemical structure, molecular interactions, and formation of chemical bonds in ZnO thin films. Optical studies show that the energy band gap widens during annealing. Optical profilometer studies verified the uniformity of the deposited film surface. According to Hall effect analysis, conversion of p to n type occurs at an annealing temperature of 450 °C. A ZnO-based MOS gas sensor was found to have better selectivity towards C2H5OH than other test gases such as NH3, NO2, and H2S. At room temperature, the sensor response and recovery time is shorter for NH3 than for C2H5OH test gas. In environmental monitoring, the present gas sensor can detect ethanol. [ABSTRACT FROM AUTHOR]

Exchange-correlation (XC) effects in carrier electrons have a significant influence on the dielectric properties and electric characteristics of a material. In this study, momentum-transfer (q) resolved electron energy-loss spectroscopy was conducted to experimentally evaluate the XC effects of carrier electrons in LaB6 bulk crystals, whose nanoparticles have been used for near-infrared-light shielding filters. By measuring q dependence of plasmon energy due to carrier electrons and evaluating the deviation from the free electron gas model in random phase approximation, the dielectric correction factor due to the XC effects, i.e., the local field correction G(q), for the carrier electrons in LaB6 were experimentally derived. This experimental result confirmed that the XC effects are non-negligible for the carrier electrons in LaB6. Because the XC effects influence dipole surface plasmon energy of LaB6 nanoparticles, the evaluation of the XC effects is important for a precise understanding of the optical properties of LaB6 nanoparticles. [ABSTRACT FROM AUTHOR]

Microwave-induced thermoacoustic imaging (TAI) is a hybrid imaging technique that combines electromagnetic radiation and ultrasonic waves to achieve high imaging contrast and submillimeter spatial resolution. These characteristics make TAI a good candidate to detect material anomalies that change the material electric properties without a noticeable variation in material density. Conventional pulsed TAI systems work by sending a single short pulse to the imaged target and then detecting the generated pressure signal; therefore, a very high peak power microwave pulse or data averaging is needed to produce images with a high signal-to-noise ratio (SNR). In this paper, we propose to enhance the SNR of pulsed TAI systems by using non-coherent pulse compression. In this approach, a predefined pulse coded signal is used to illuminate the imaged sample and the received pressure signal is cross correlated with a template that is related to the power profile of the excitation signal. The proposed approach can be easily deployed to pulsed TAI systems without the need for major system modifications to the RF source because it only requires a timing circuit to control the triggering time of the RF pulses. In this paper, we demonstrate experimentally that the proposed approach highly improves the SNR of TAI signals and images and can be used to reduce the acquisition time by lowering the number of data averaging or reduce the required peak power from RF sources. [ABSTRACT FROM AUTHOR]

The imbalanced carrier mobility remains a bottleneck for performance breakthrough in even those organic solar cells (OSCs) with recorded power conversion efficiencies (PCEs). Herein, a counter electrode doping strategy is proposed to reshape the internal potential distribution, which targets to extract the low mobility carriers at far end. Device simulations reveal that the key of this strategy is to partially dope the active layer with a certain depth, therefore it strengthens the electric field for low mobility carriers near counter electrode region while avoids zeroing the electric field near collection electrode region. Taking advantage of these, PCE enhancements are obtained from 15.4% to 16.2% and from 16.9% to 18.0%, respectively, via cathode p-doping and anode n-doping. Extending its application from opaque to semitransparent devices, the PCE of dilute cell rises from 10.5% to 12.1%, with a high light utilization efficiency (LUE) of 3.5%. The findings provide practical solutions to the core device physical problem in OSCs. [ABSTRACT FROM AUTHOR]

Dust accumulation on PV surface panels is a crucial factor affecting their performance. It is more frequently noted in the desert zones. The effect of dust on the electrical behavior of damaged PV panels was investigated in this study. Three panels are used: the degraded panels (with and without dust) and the reference panels; they are located in an industrial zone with a continental climate (Bordj Bou Arréridj, Algeria). The I-V and P-V characterization and degradation mechanism visualization are used. Also, a numerical simulation was conducted to calculate the five parameters of the three modeled PV panels (diode ideality factor (a), series resistance (Rs), Shunt resistance (Rp), photocurrent (Ipv), and diode saturation current (I0)). These parameters were utilized for the first time to study the impact of dust on their degradation rate and the PV panel behavior. The degradation rate and the annual degradation rate of each parameter are affected by dust differently. The power degradation rate is increased by 5.45%. The Isc and Imax degradation rates are climbed by 6.97% and 6.0%, respectively. Vmax and Voc degradation rates decrease by 1.20% and 0.35%, respectively. Dust increased the rate of degradation for a, Iph, and I0 by 4.12%, 6.99%, and 68.17%, respectively. For Rs and Rp, the degradation rate was reduced by 4.51% and 20.01%, respectively. An appropriate netoiling approach must be considered because dust, even in non-desert areas and industrial zones, has a significant impact on the electrical characteristics degradation of a PV panel. [ABSTRACT FROM AUTHOR]

Electrical resistance tomography (ERT) provides images of the electrical properties of subsurface materials leading to the distinction of different Earth's interior structures. The accuracy of electrical resistance imaging is strongly affected by the topographical variations so the lack of incorporation of topography information into the inversion process may produce erroneous anomalies in the resistivity section. Owing to the significance of the topography effects on the resistivity measurements, we use the Schwarz-Christoffel transformation approach to incorporate the irregular surface into the 2.5-dimensional forward solution in the framework of the finite difference method. This approach is implemented on synthetic cases to illustrate how the resistivity measurements are dependent on the topographic irregularities. Numerical experiments demonstrate that in the presence of topographic features between current and potential electrodes, the resistivity response does not reflect the realistic resistivity values of the subsurface even in the case of a homogeneous resistivity distribution. [ABSTRACT FROM AUTHOR]

The document discusses the recent International Conference on Computational Electromagnetics (CEM) held in Cannes, France in April 2023. It highlights the key areas covered in the conference, including computational techniques for solving electromagnetics problems, numerical methods, and applications of computational electromagnetics. The document also presents summaries of six selected papers from the conference, covering topics such as optimization of permanent magnet motors, reduced order modeling for electromagnetic analysis, and time reversal methods for partial discharge location. Additionally, it announces the upcoming CEM 12 conference scheduled for April 2025 in Bruges, Belgium, welcoming original contributions in the field of computational electromagnetics. [Extracted from the article]

In the field of roads, due to the effect of vehicle loads, piezoelectric materials under the road surface can convert mechanical vibration into electrical energy, which can be further used in road facilities such as traffic signals and street lamps. The barium titanate/polyvinylidene fluoride (BaTiO3/PVDF) composite, the most common hybrid ceramic-polymer system, was widely used in various fields because the composite combines the good dielectric property of ceramic materials with the good flexibility of PVDF material. Previous studies have found that conductive particles can further improve the dielectric and piezoelectric properties of other composites. However, few studies have investigated the effect of conductive carbon black on the dielectric and piezoelectric properties of BaTiO3/PVDF composites. In this study, BaTiO3/PVDF/conductive carbon black composites were prepared with various conductive carbon black contents based on the optimum ratio of BaTiO3 to PVDF. The effects of conductive carbon black content on the morphologies, thermal performance, conductivities, dielectric properties, and piezoelectric properties of the BaTiO3/PVDF/conductive carbon black composites were then investigated. The addition of conductive carbon black greatly enhances the conductivities, dielectric properties, and piezoelectric properties of the BaTiO3/PVDF/conductive carbon black composites, especially when the carbon black content is 0.8% by weight of PVDF. Additionally, the conductive carbon black does not have an obvious effect on the morphologies and thermal stabilities of BaTiO3/PVDF/conductive carbon black composites. [ABSTRACT FROM AUTHOR]

Engineering materials through the introduction of point defects has resulted in significant advances in semiconductor processing and, more recently, the observation of novel phenomena such as large reconfigurable strains in ferroelectrics as a result of defect dipole complexes. Up to 0.8% strain has been demonstrated in BaTiO3 crystals dilutely doped with iron. However, the defect dipole pinning sites and the corresponding achievable strains are found to degrade as the crystal is electrically cycled as part of the measurement process. The strain degradation rate is dependent on the applied field values but shows an exponential change in materials properties regardless of the electric field. This behavior, plus a change in impedance with number of times cycled, suggests these changes are due to electric field induced oxygen migration—similar to the cause of the resistance degradation effect. Despite this, effective piezoelectric coefficients of over 4700 pm/V were recorded with 1.5 kV/cm fields, one of the largest values for a lead-free piezoelectric material thus far. In addition, the defect dipole-aligned state and the high strains can be repeatably recovered by a subsequent heat treatment step after cycling. Potential paths to exploiting the defect dipole induced effects and large piezoelectric coefficient in these dilutely doped systems are proposed. [ABSTRACT FROM AUTHOR]

3D-printed electronics belong to new approaches to how to build a complex object with multiple desired functions. For that purpose, materials with specific electric properties are needed: conductors, insulators, magnetics, or dielectrics with high permittivity. However, such materials are not commonly available in the form of filament for fused deposition modelling since the development is still ongoing. This paper describes the electrical properties of PETG-ceramic composite filaments. PETG (polyethylene terephthalate glycol-modified) was filled with titanium dioxide (10 and 20 wt.%) to increase the dielectric constant and, simultaneously, to preserve printing simplicity as the material key advantage. Dielectric spectroscopy and measurement of volume resistivity were performed on printed samples. Relative permittivity increased by 50% for a composite filled with 20 wt.% of ceramic particles (εr = 2.5÷4.4) against pure PETG. Permittivity and dielectric loss exhibited frequency and temperature independence. The prepared composite can be used for dielectric applications in electronics. [ABSTRACT FROM AUTHOR]

• Establishment of a high-field piezoelectric impedance spectrum measurement system. • A methodology to determine different loss factors of piezoelectric materials. • Properties of PMN-PT single crystal 1–3 composites at different driving voltages. • Variation of complex material parameters with increasing electric field. It is essential to characterize the high-field properties of piezoelectric composites for their applications in ultrasonic transducers. This study involved the development of an experimental characterization system of piezoelectric impedance spectra and mechanical quality factors under high-field conditions to analyze the properties of PMN-PT piezoelectric single-crystal composites. The impedance spectra and mechanical quality factors of a [0 0 1] c -poled 0.69PMN-0.31PT single crystal/epoxy 1–3 composite disk with filling ratio φ = 0.4 under thickness resonance mode were tested at different driving voltages ranging from 1 to 120 V pp to explore the influence of AC electric field on the material properties. By utilizing a theoretical approach, an evaluation was conducted on the variations in the material properties such as stiffness, permittivity, piezoelectric coefficient, and electromechanical coupling factor, along with respective loss factors. Our results suggest that as the AC electric field increases, the elastic modulus c 33 D and the mechanical quality factor Q m decrease, while the piezoelectric strain coefficient d 33 and the electromechanical coupling factor k t increase. However, the dielectric coefficient ε 33 X does not show an obvious change in this field range. Furthermore, the elastic loss factor tan ϕ , the dielectric loss factor tan δ 33 ′ , the piezoelectric loss factor tan θ 33 ′ , and the electromechanical coupling loss factor tan χ t all increase, indicating that the loss of the piezoelectric composite becomes more evident as the AC electric field grows. [ABSTRACT FROM AUTHOR]

An exact geometry hybrid-mixed four-node laminated piezoelectric solid–shell element with temperature-dependent material properties using the sampling surfaces (SaS) method is proposed. The SaS method is based on the choice of an arbitrary number of SaS located at Chebyshev polynomial nodes inside the layers and interfaces to introduce temperatures, displacements and electric potentials of these surfaces as fundamental shell unknowns. This choice of unknowns with the use of Lagrange polynomials in the through-thickness approximations of temperature, temperature gradient, displacements, strains, electric potential, electric field and material properties leads to a compact and effective higher-order thermopiezoelectric shell formulation with temperature-dependent material properties. The developed hybrid-mixed piezoelectric solid–shell element is based on the Hu–Washizu variational principle and three-dimensional (3D) analytical integration, which provides excellent performance for coarse meshes. It can be useful for the 3D thermoelectroelastic analysis of thick and thin laminated piezoelectric shells under thermo-electro-mechanical loading, since the SaS shell formulation makes it possible to obtain the numerical solutions with a prescribed accuracy, which asymptotically approach exact solutions of the theory of thermopiezoelectricity as the number of SaS goes to infinity. [ABSTRACT FROM AUTHOR]

As the electrical properties of biological tissues are highly sensitive to their physiological and pathological status, the noninvasive imaging method of electrical properties also has drawn much attention. Thermo-acoustic tomography with electric excitation (TATE) is a typical noninvasive method of electrical properties for biological tissues. To the best of our knowledge, however, there is no 3D simulation model of TATE. In this paper, a new mathematical model is built, and the 3D TATE equations have been deduced. The performance of TATE has been studied by a series of 3D simulation models, including the tumors with different background tissues, different sizes, and different conductivities. In the simulation results, the Joule heat distribution of tumors has been imaged clearly. In addition, a verification experiment has validated the mathematical model and simulation results. The simulation and experiment results also indicate that the mathematical model can describe TATE well and TATE has the potential to image the tumors with high contrast and high resolution. [ABSTRACT FROM AUTHOR]

High-frequency coaxial waveguide measurements are used to evaluate composition- and frequency-dependent complex permittivities and permeabilities of polycrystalline ferroelectric and ferrimagnetic ceramics. Material dielectric and magnetic property measurements were performed on ferroelectric barium titanate (BaTiO3) and ferrimagnetic yttrium iron garnet (YIG), with the upper measurement frequency bound below gyromagnetic resonance of YIG. These polycrystalline materials were chosen because of their widespread use in voltage- and magnetic field-tunable devices. Wideband frequency material measurements were used to predict dielectric and magnetic properties of various two-phase composite media incorporating BaTiO3 and YIG. Two effective medium theories were used: an asymmetric, modified Maxwell-Garnett type and a symmetric Bruggeman model. The Bruggeman effective medium model is extended to include three-phases. The three-phase Bruggeman predictive model is employed when controlled porosity is introduced into the composite and when two component phases are combined with polytetrafluoroethylene. [ABSTRACT FROM AUTHOR]

Phase change memory has been considered as the next generation in non-volatile electronic data storage. The property modulation of such materials by the doping of rare-earth elements has drawn a lot of attention, which motivates us to search for the optimal dopants and reveal the underlying mechanisms. Here, we investigate the role of Gd as a dopant in Ge2Sb2Te5, which exhibits higher crystalline resistance and better thermal stability and antioxidant capacity than the undoped counterpart. Moreover, Gd dopants suppress both the processes of phase transition and grain growth. The crystalline structure remains unchanged with Gd dopants and vacancies are randomly distributed. Furthermore, the bonding mechanism was theoretically investigated. In the amorphous state, Gd atoms modify the local structures around Ge, Sb, and Te atoms. The large coordination number of Gd and the "Gd–Te distorted pentagonal bipyramidal-like" structure can be attributed to the good thermal stability. These microscopic findings figure out some of the key issues about the bonding mechanism, electrical properties, and crystallization behaviors of Gd doped phase change memory materials, which could be useful for storage devices. [ABSTRACT FROM AUTHOR]

Tin sulfides, SnxSy, are an important class of materials that are actively investigated as novel photovoltaic and water splitting materials. A first-principles evolutionary crystal structure search is performed with the goal of constructing the complete phase diagram of SnxSy and discovering new phases as well as new compounds of varying stoichiometry at ambient conditions and pressures up to 100 GPa. The ambient phase of SnS2 with P 3 ¯ m 1 symmetry remains stable up to 28 GPa. Another ambient phase, SnS, experiences a series of phase transformations including α-SnS to β-SnS at 9 GPa, followed by β-SnS to γ-SnS at 40 GPa. γ-SnS is a new high-pressure metallic phase with P m 3 ¯ m space group symmetry stable up to 100 GPa, which becomes a superconductor with a maximum Tc = 9.74 K at 40 GPa. Another new metallic compound, Sn3S4 with I 4 ¯ 3 d space group symmetry, is predicted to be stable at pressures above 15 GPa, which also becomes a superconductor with relatively high Tc = 21.9 K at 30 GPa. [ABSTRACT FROM AUTHOR]

Lithium metal orthosilicates, Li2MSiO4 (M = Fe, Mn, Co, Ni, and their mixtures), have been attracting significant attention as alternative cathodes for next‐generation high energy Li‐ion batteries (LIBs). The high capacity of these cathodes is attributed to two reversible transitions, those of Li2MSiO4 to LiMSiO4 and LiMSiO4 to MSiO4 phases involving two Li+ ions per mole. However, due to their complex structures and phase transformation behaviors, these materials are not yet available for practical commercial applications. Rate capability is one of the most important properties of cathode materials that are affected by phase transformations. This review will comprehensively summarize the current knowledge of the rate‐dependent phase transformations of Li2MSiO4 materials based on various characterization tools to facilitate future developments of these high potential cathode materials for future LIBs. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) have much more attention in energy applications owing to their optical and electrical properties. To overcome the problems associated with these polymers, the Up-Conversion Carbon Quantum Dot (UC-CQD) based materials are employed. That has more desirable features, like hydrophilicity, low toxicity, and high water solubility. The UC-CQD in the electrochemical field is creating great attention to photoluminescent behaviors and low specific capacitance. When UC-CQD is combined with the conducting polymers, the optical properties are enhanced with the help of energy transfer processes. By the advantage of electropolymerization technique, the solubility problems are tackled, because the monomer has coated on the substrate. Herein, the preparation and characterization of the UC-CQD doped, PPy, and PTh films have been reported and their optical and electrical properties are investigated. The band gap of PPy and PPy-CQD is analysed from Tauc plot and calculated to be 2.54 and 1.69 eV respectively. The 50% and 60% mass loss were observed in thermogravimetric analysis for PPy and PPy-CQD respectively. These materials can be used for organic solar cell applications in near future. [ABSTRACT FROM AUTHOR]

Recent years have seen a considerable research interest in multiferroic materials for their potential application as sensors and actuators. However, the scarcity of these materials in a single phase and the weak coupling of their ferroic components have directed research toward multiferroic heterostructures. These systems operate by coupling the magnetic and electric properties of two materials, generally ferromagnetic and ferroelectric, via strain. In this paper, thin films have been grown by chemical solution deposition (CSD) using spin coating technique using rotations peed of 4500 rpm and time of 50 s and dried at 120○C for 20 min. The optical, dielectric, magnetic, ferroelectric, ferromagnetic, and piezoelectric properties of thin films have been investigated by Uv- Visible spectrophotometer (300-2500) nm, X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM) respectively. PZT/CFO thin films deposited at different temperatures from 400 °C, 500 °C and 600 °C. The as-deposited PZT/CFO show week piezoelectricity and the effective piezoelectric coefficient d33 because the materials deposited on the films not only the PZT layer but also the CFO layer, which decreases the piezoelectricity of these films. PZT/CFO Films were then recorded to enhance all physical properties (dielectric, optical, structural, surface morphology, and magnetic properties) as the sintering temperature increased. The images of a thin film before and after treatment with Nd-YAG, which have Power from 10 mw to 5300 mw, Pulse width: 7 ns pulsed laser, Repetition Rate: 10 HZ, and wavelength spectrum in (IR, Vis) laser beam indicate that sample prepared before treated has a lot of porous and agglomeration which decreases after treatment. [ABSTRACT FROM AUTHOR]

To prepare nonwoven mats constituted by submicrometric fibers of thermally responsive biopolyurethanes (TPU) modified with multiwalled carbon nanotubes (MWCNT), solution blow spinning (SBS) was used. The TPU was the product of synthesis using poly(butylene sebacate)diol, PBSD, ethyl ester L-lysine diisocyanate (LDI), and 1,3-propanediol (PD) (PBSe:LDI:PD) as reactants. TPU was modified by adding different amounts of MWCNT (0, 0.5, 1, 2, and 3 wt.%). The effect of the presence and amount of MWCNT on the morphology and structure of the materials was studied using field-emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR), respectively, while their influence on the thermal and electric behaviors was studied using differential scanning calorimetry (DSC) and capacitance measurements, respectively. The addition of MWCNT by SBS induced morphological changes in the fibrous materials, affecting the relative amount and size of submicrometric fibers and, therefore, the porosity. As the MWCNT content increased, the diameter of the fibers increased and their relative amount with respect to all morphological microfeatures increased, leading to a more compact microstructure with lower porosity. The highly porous fibrous morphology of TPU-based materials achieved by SBS allowed turning a hydrophilic material to a highly hydrophobic one. Percolation of MWCNT was attained between 2 and 3 wt.%, affecting not only the electric properties of the materials but also their thermal behavior. [ABSTRACT FROM AUTHOR]

Expanding new avenues for renewable energy and reducing the consumption of fossil fuels in a time of ever-increasing demand for energy is challenging. Thermoelectricity, associated with generating electric power due to an applied temperature gradient or thermal flow due to an applied voltage, offers the potential to utilize some of this "free" energy in all-solid-state conversion devices for power generation. [Extracted from the article]

We have developed a novel lead-free multiferroic composites (1-x) (Bi 0.5 Na 0.5 TiO 3) 0.94 -(BaTiO 3) 0.06 + (x) SrCe 0.05 Sm 0.05 Fe 11.9 O 19 ; (x = 0.00, 20, 40, 60, 80 and 100 %) synthesized by sol–gel and solid-state reaction methods. Rietveld refinement of X-ray diffraction (XRD) patterns revealed the presence of two distinct phases, tetragonal (P4bm) and hexagonal (P63/mmc), in the prepared composites. Morphological analysis was carried out by using a field emission scanning electron microscope (FESEM), which showed the formation of plate-like structures. The identification of ferrite and ferroelectric grains was accomplished through energy dispersive X-ray analysis (EDX). Additionally, high-resolution transmission electron microscopy (HR-TEM) was employed to estimate the average particle size of the samples, which fell within the range of 189 to 115 nm. Fourier transform infrared spectroscopy (FTIR) was employed, and the data from all the composites indicated the formation of dual-phase compounds with limited interfacial diffusion, preserving the primary crystallographic phases. Magnetic studies were conducted using a vibratingsample magnetometer (VSM) at room temperature, revealing that the ferromagnetic behavior decreases with increasing concentration of ferroelectric phase in the composite Dielectric properties were investigated using an LCR meter, and charge conduction and relaxation in the system were interpreted using Koop and Maxwell-Wagner's model. Complex impedance, the complex electric Cole-Cole diagram, and frequency-dependent AC conductivity analysis were utilized to examine relaxation and conduction mechanisms in the samples. Polarization with electric field measurements were carried out to investigate the ferroelectric nature of the prepared samples. Magnetoelectric-coupling were investigated of the composite samples. [ABSTRACT FROM AUTHOR]

Electronic gaps play an important role in the electric and optical properties of materials. Although various experimental techniques, such as scanning tunnelling spectroscopy and optical or photoemission spectroscopy, are normally used to perform electronic band structure characterizations, it is still challenging to measure the electronic gap at the nanoscale under ambient conditions. Here we report a scanning probe microscopic technique to characterize the electronic gap with nanometre resolution at room temperature and ambient pressure. The technique probes the electronic gap by monitoring the changes of the local quantum capacitance via the Coulomb force at a mesoscopic scale. We showcase this technique by characterizing several 2D semiconductors and van der Waals heterostructures under ambient conditions. The nanoscale measurement of electronic bandgaps is crucial for material characterization, but it is usually performed under cryogenic conditions. Here, the authors report a scanning probe method to determine the electronic bandgap of 2D semiconductors at the nanoscale by monitoring their quantum capacitance under ambient conditions. [ABSTRACT FROM AUTHOR]

Examples of electric properties of various crystalline materials, insulators and semiconductors, liquid crystals, films, and nanostructures are presented. Among crystals, particular attention is paid to piezoelectrics, pyroelectrics, and ferroelectrics, whose dielectric properties depend strongly on the external electric field and temperature. The electro-optic properties of these materials, as well as the photovoltaic effect and photorefraction, are considered. Liquid crystals, whose optical properties depend strongly on applied electric field, are considered separately. The electric properties of materials are widely used in most diverse fields of science and technology. [ABSTRACT FROM AUTHOR]

Infrared (IR) optical fibers based on crystals and ceramics of the AgBr–AgI system are transparent in the IR range from 3 to 26 μm, which is of interest for thermal imaging, laser technique, and spectroscopy. High photo- and radiation resistances make these materials especially attractive for solving the problems of optical radiation transfer in aggressive environment. To design optical equipment, it is necessary to have information on the electric properties of materials, which are most completely characterized by current–voltage characteristics (CVCs). In this work, we consider the dependences of the CVCs of optical materials of the AgBr–AgI system in the form of plates with thicknesses from 0.1 to 1.7 mm and AgI concentrations from 4 to 76 mol % on the composition and temperature in the range of 298–453 K. It is found that an increase in the AgI concentration in the AgBr–AgI crystals leads to a decrease in electric conductivity. The conductivity of AgBr–AgI ceramics is two–three orders of magnitude higher than that of the corresponding crystals at the same temperatures and applied voltages. The conductivity of ceramics is comparable with the conductivity of solid electrolytes. The β-AgI–α-AgI phase transition at a temperature of 463 K causes a jump in the conductivity of the AgBr–AgI ceramics. The IR transmission of the studied material was measured before and after electrical breakdown. It was found that electrical breakdown decreases the transmission by more than 20% in the entire spectral range. Information on the breakdown voltage for materials of the AgBr–AgI system with different compositions is important for ensuring reliability and safety of electrotechnical equipment using optical devices based on these materials. In this study, we observed deterioration of the optical properties of crystalline materials of the AgBr–AgI system with applying some voltage difference and determined the breakdown voltage. The breakdown voltage is determined by applying direct-current voltage, but it is the same in the case of alternating-current voltage. [ABSTRACT FROM AUTHOR]

In order to obtain a long-range magnetic order in 2D ferromagnetism materials at suitable temperature, researchers have established some theories, such as shape anisotropy, exchange anisotropy and magnetoelastic anisotropy, and many 2D ferromagnetic materials have also been successfully synthesized. Furthermore, the separation of the zero-field cooled and the field cooled curves was observed due to the increase in the anisotropy field to a size comparable or larger than that of the measuring field. Lin et al. explored the influence of Gd SP 3+ sp doping on the ferroelectric and magnetic properties of BFO films. Similarly, Hu et al. prepared multilayer BiFeO SB 3 sb /BaTiO SB 3 sb samples and systemically studied their magneto-electric effect. [Extracted from the article]

This review aims to consolidate scattered literature on thermally sprayed coatings with nonionizing electromagnetic (EM) wave absorption and shielding over specific wavelengths potentially useful in diverse applications (e.g., microwave to millimeter wave, solar selective, photocatalytic, interference shielding, thermal barrier‐heat/emissivity). Materials EM properties such as electric permittivity, magnetic permeability, electrical conductivity, and dielectric loss are critical due to which a material can respond to absorbed, reflected, transmitted, or may excite surface electromagnetic waves at frequencies typical of electromagnetic radiations. Thermal spraying is a standard industrial practice used for depositing coatings where the sprayed layer is formed by successive impact of fully or partially molten droplets/particles of a material exposed to high or moderate temperatures and velocities. However, as an emerging novel application of an existing thermal spray techniques, some special considerations are warranted for targeted development involving relevant characterization. Key potential research areas of development relating to material selection and coating fabrication strategies and their impact on existing practices in the field are identified. The study shows a research gap in the feedstock materials design and doping, and their complex selection covered by thermally sprayed coatings that can be critical to advancing applications exploiting their electromagnetic properties. [ABSTRACT FROM AUTHOR]

The decarbonization of energy to meet the low-carbon energy strategy set for 2050 has led to a continuous increase in the contribution of electricity generated from renewables to our growing energy demands, where their inherent intermittency of supply must be addressed by a step-change in energy storage. 10.3390/en14041139 2 Mirzaeian M., Abbas Q., Hunt M.R.C., Hall P. Pseudocapacitive Effect of Carbons Doped with Different Functional Groups as Electrode Materials for Electrochemical Capacitors. Additionally, the nonstop emerging demands of modern technologies still require the design of versatile energy-storage/power supply systems, ensuring a secure and continuous supply of energy on a large scale with wide ranges of power and energy densities commensurate with each application. [Extracted from the article]

Perovskite solid solution materials, namely, 0.67BiFeO 3 -0.33BaTiO 3 , were synthesized by spark plasma sintering method. The effects of the spark plasma sintering temperature on phase purity, microstructure, and electric properties of the as-prepared materials were investigated. The materials could be referred as pseudocubic phases based on the X-ray diffraction patterns. The bulk density first increased and then decreased. The 880 °C-sintered-ceramics had the maximal density and a compact microstructure with grain size of 0.77 ± 0.34 μm. The dielectric constant as a function of temperature exhibited a broad peak. At the optimal spark-plasma-sintering temperature, enhanced ferroelectric properties were observed with a value of P r ∼ 21 μC/cm2. This investigation on the spark plasma sintering process confirms it as an efficient approach to prepare outstanding performance BiFeO 3 –BaTiO 3 ceramics. [ABSTRACT FROM AUTHOR]

The phenomenon of electrical conductivity maxima of molten salts versus temperature during orthobaric (closed-vessel) conditions is further examined via ab initio simulations. Previously, in a study of molten BiCl3, a new theory was offered in which the conductivity falloff at high temperatures is due not to traditional ion association, but to a rise in the activation energy for atomic ions hopping from counterion to counterion. Here this theory is further tested on two more inorganic melts which exhibit conductivity maxima: another high-conducting melt (SnCl2, αmax = 2.81 Ω-1 cm-1) and a low-conducting one (HgBr2, smax = 4.06 10-4 Ω-1 cm-1). First, ab initio molecular dynamics simulations were performed and again appear successful in reproducing the maxima for both these liquids. Second, analysis of the simulated liquid structure (radial distributions, species concentrations) was performed. In the HgBr2 case, a very molecular liquid like water, a clear Grotthuss chain of bromide transfers was observed in simulation when seeding the system with a HgBr+ cation and HgBr3 - anion. The first conclusion is that the hopping mechanism offered for molten BiCl3 is simply the Grotthuss mechanism for conduction, applicable not just to H+ ions, but also to halide ions in post-transition-metal halide melts. Second, it is conjectured that the conductivity maximum is due to rising activation energy in network-covalent (halide-bridging) melts (BiCl3, SnCl2, PbCl2), but possibly a falling Arrhenius prefactor (collision frequency) for molecular melts (HgBr2). [ABSTRACT FROM AUTHOR]

The phenomenon of electrical conductivity maxima of molten salts versus temperature during orthobaric (closed-vessel) conditions is further examined via ab initio simulations. Previously, in a study of molten BiCl3, a new theory was offered in which the conductivity falloff at high temperatures is due not to traditional ion association, but to a rise in the activation energy for atomic ions hopping from counterion to counterion. Here this theory is further tested on two more inorganic melts which exhibit conductivity maxima: another high-conducting melt (SnCl2, αmax = 2.81 Ω-1 cm-1) and a low-conducting one (HgBr2, smax = 4.06 10-4 Ω-1 cm-1). First, ab initio molecular dynamics simulations were performed and again appear successful in reproducing the maxima for both these liquids. Second, analysis of the simulated liquid structure (radial distributions, species concentrations) was performed. In the HgBr2 case, a very molecular liquid like water, a clear Grotthuss chain of bromide transfers was observed in simulation when seeding the system with a HgBr+ cation and HgBr3 - anion. The first conclusion is that the hopping mechanism offered for molten BiCl3 is simply the Grotthuss mechanism for conduction, applicable not just to H+ ions, but also to halide ions in post-transition-metal halide melts. Second, it is conjectured that the conductivity maximum is due to rising activation energy in network-covalent (halide-bridging) melts (BiCl3, SnCl2, PbCl2), but possibly a falling Arrhenius prefactor (collision frequency) for molecular melts (HgBr2). [ABSTRACT FROM AUTHOR]

Many factors have been identified to influence the electrical transport characteristics of graphene field-effect transistors. In this report, we examine the influence of the exposure current level used during electron beam lithography (EBL) for active region patterning. In the presence of a self-assembled hydrophobic residual layer generated by oxygen plasma etching covering the top surface of the graphene channel, we show that the use of low EBL current level results in higher mobility, lower residual carrier density, and charge neutrality point closer to 0V, with reduced device-to-device variations. We show that this correlation originates from the resist heating dependent release of radicals from the resist material, near its interface with graphene, and its subsequent trapping by the hydrophobic polymer layer. Using a general model for resist heating, we calculate the difference in resist heating for different EBL current levels. We further corroborate our argument through control experiments, where radicals are either intentionally added or removed by other processes. We also utilize this finding to obtain mobilities in excess of 18 000 cm2/V s on silicon dioxide substrates. We believe these results are applicable to other 2D materials such as transition metal dichalcogenides and nanoscale devices in general. [ABSTRACT FROM AUTHOR]

Multilayer iron-doped indium-saving indiumtin oxide (ML ITO50:Fe2O3) thin films with high conductivity and high transmittance in the visible spectrum have been fabricated by sputtering method. Structures consisting of very thin layer of conventional indium tin oxide (90 mass% In2O310 mass% SnO2) and iron-doped indium-saving indiumtin oxide layer with reduced content of In2O3 (ITO50:Fe2O3) to 50 mass% are discussed. By optimizing oxygen flow rate in iron-doped indium-saving indiumtin oxide layer, the lowest volume resistivity of 3.78 × 10-4·cm, mobility of 29.8cm2/(V·s), carrier concentration of 4.60 × 1020 cm-3 and transmittance larger than 90% in the visible range have been achieved. ML ITO50:Fe2O3 thin films deposited under optimal conditions demonstrated lower volume resistivity and higher transmittance than undoped multilayer indium-saving ITO thin films and iron-doped single-layer thin films obtained under the same oxygen flow rate Q(O2) = 0.1 sccm. ML ITO50:Fe2O3 thin films demonstrated optimal parameters at the lower oxygen flow rate (Q(O2) = 0.1 sccm) than undoped ML ITO50 thin films. ML ITO50:Fe2O3 thin films are crystallized and show In4Sn3O12 structure. [ABSTRACT FROM AUTHOR]

ZnO nanosheets were fabricated on a silver-metalized polyimide (PI/Ag) substrate using electrochemical deposition. FE-SEM, XRD, UV--Vis absorption, and I-V measurements were employed to examine the structural, optical and electrical properties of silvermetalized PI film and ZnO deposited PI/Ag film. For a comparison, PI/Ag film was also investigated without ZnO layer. FE-SEM analysis indicated that a silver film layer, consisted of spherical Ag nanoparticles, and the ZnO nanosheets were synthesized on PI substrate by electroless and electrochemical deposition, respectively. Moreover, the growth mechanism of the Ag film and ZnO nanosheets was also discussed. The characterization of X-ray diffraction verified that the ZnO nanosheets had a hexagonal phase and grew along the [002] direction. The optical absorbance spectra of bare PI, PI/Ag, and PI/Ag/ZnO showed a broad absorption peak around 300 nm. The electrical properties of the PI/Ag and PI/Ag/ ZnO samples were studied by current-voltage (I-V) measurements in the dark environment at room temperature (300 K). The I-V measurements suggested that the samples presented ohmic characteristics. The results revealed that the deposition of ZnO on PI/Ag substrate improved the electrical conductivity compare with bare PI/Ag. [ABSTRACT FROM AUTHOR]

Nickel sulfide (NiS) thin film has been deposited on glass substrates by spray-pyrolysis at 325 ± 5 °C. The precursor aqueous solution was synthetized using hexahydrated nickel nitrates and thiourea. The structural, morphological, optical and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and four probes electrical measurements. The XRD analysis confirmed the hexagonal structure of NiS thin film, which was found to crystalize along [010] direction with an average crystallites size of 10.5 nm. The lattice parameters are a = b = 3.420 Å and c = 5.300 Å in the space group P63/mmc. The optical properties of the films were investigated through the transmittance and the reflectance measurements. The results revealed that the material exhibits a direct optical band gap of 1.03 eV. The elementary composition analysis confirmed the presence of Ni and S with a stoichiometry ratio (Ni/S) of 1.05. The morphology analysis revealed a homogenous crack-free, compact appearance and a granular surface in all scanned areas. The average roughness of the surface was 6.48 nm. On the other hand, the film exhibits a high electrical conductivity ca. 1.10 x 105 S/cm at room temperature. The above results show that the prepared NiS in this study has a good crystallization, dense morphology, good stoichiometric ratio and high conductivity; therefore, it stands as a potential candidate for application in supercapacitors as an electrode material. [ABSTRACT FROM AUTHOR]

This paper focuses on the potential of epoxy resin/aluminum nitride (EP/AIN) nanocomposites through experiments and simulation for the packaging material of a 15 kV SiC-IGBT module. For this purpose, space charge, AC breakdown, thermal conductivity and glass transition temperature $(T_{\mathrm{g}})$ are measured. The electric stress reduction effect in EP/AIN nanocomposites is compared to the traditional packaging material at high-frequency AC and square voltages at 150 °C using the electric field simulation. The experimental results show that the 2 wt% EP/AIN nanocomposite exhibits the least space charge accumulation, highest AC breakdown strength and $T_{\mathrm{g}}$ amongst the tested nanocomposites. The offset of metallization layers plays a crucial role in the impact of the electrical properties of packaging materials on the electric field of the packaging structure. When the offset of metallization layers is zero, the maximum electric stress in the EP/AIN nanocomposites is lower than the traditional packaging material, both under the AC and square voltages. In the EP/AIN nanocomposites, as the frequency or the nano-AIN content increases, the maximum electric stress decreases under the AC voltages. Traditional packaging materials have a steeper transient electric field variation than EP/AIN nanocomposites, although the transient process is smoother at higher frequencies under square voltages for all the considered materials. A simplified physical model is proposed to explain the electric field distribution variation in the packaging structure under the AC voltages. [ABSTRACT FROM AUTHOR]

Diodes incorporating a bilayer of an organic semiconductor and a wide bandgap metal oxide can show unipolar, non-volatile memory behavior after electroforming. The prolonged bias voltage stress induces defects in the metal oxide with an areal density exceeding 1017m-2. We explain the electrical bistability by the coexistence of two thermodynamically stable phases at the interface between an organic semiconductor and metal oxide. One phase contains mainly ionized defects and has a low work function, while the other phase has mainly neutral defects and a high work function. In the diodes, domains of the phase with a low work function constitute current filaments. The phase composition and critical temperature are derived from a 2D Ising model as a function of chemical potential. The model predicts filamentary conduction exhibiting a negative differential resistance and nonvolatile memory behavior. The model is expected to be generally applicable to any bilayer system that shows unipolar resistive switching. [ABSTRACT FROM AUTHOR]