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Hydrogen‐bonded organic frameworks (HOFs) are crystalline materials assembled by intermolecular hydrogen‐bonding interactions, and their hydrogen‐bonding structures are effective pathways for proton transport. Herein, we synthesize iHOF‐45 using 4,4'‐diaminodiphenylmethane and 1,3,6,8‐pyrenetetrasulfonicacid sodium salt with 2D hydrogen‐bonding networks. The stability of ionic HOFs (iHOFs) can be enhanced by introducing ionic bonds in addition to hydrogen‐bonding forces. Thermal analyses demonstrated that iHOF‐45 exhibited excellent thermal stability up to 332 °C. The proton conductivity of iHOF‐45 was evaluated, demonstrating a notable increase with rising temperature and RH. At 100 °C and 98 % RH, the conductivity reached 5.25×10−3 S cm−1. The activation energy (Ea) of iHOF‐45 was calculated to be 0.281 eV for 98 % RH, and the proton conduction was attributed to the Grotthuss mechanism, whereby the protons were transported in 2D hydrogen‐bonding networks. Moreover, iHOF‐45 was doped into SPEEK to prepare composite membranes, the proton conductivity of the 15 % iHOF‐45/SPEEK membrane reached 9.52×10−2 S cm−1 at 80 °C and 98 % RH, representing a 45.1 % increase over that of the SPEEK. This suggests that doping enhances the proton conductivity of SPEEK and providing a reference for the development of high proton conductivity materials. [ABSTRACT FROM AUTHOR]

Mg+-ion-conducting tamarind gum (TG)-based biopolymer electrolytes (BPEs) are prepared by a simple solution-casting technique. XRD and FTIR analyses have revealed the dissociation and complexation of the salt with the polymer host. The glass transition temperature is observed for all the prepared electrolytes using differential scanning calorimetry (DSC). By using AC impedance analysis, the higher ionic conductivity calculated for the sample 1-g TG with 0.5 g of salt (5 TML) is 3.48 × 10−3 S/cm. The temperature-dependent conduction mechanism of sample 5 TML follows three models: region I obeys the overlapping-large polaron tunneling (OLPT) model, the quantum mechanical tunneling (QMT) model is observed in region II, and region III obeys the nonoverlapping small polaron tunneling (NSPT) model. The minimum activation energy of 0.045 eV is observed for sample 5 TML according to the Arrhenius plot. The complex dielectric permittivity and dielectric modulus spectra are discussed. The relaxation time (τ) attained by tangent analysis for 5 TML is 7.94 × 10−7 s. From the transference number measurement, it is concluded that the conductivity is mostly due to the transfer of ions only. Using the 5 TML sample, a symmetrical supercapacitor and an electrochemical cell are fabricated. Cyclic voltammetry (CV) reveals a specific capacitance of 413.05 Fg−1 at a low scan rate of 15 mV/s. From the GCD data, the power and energy density are calculated as 1499 W/kg and 100 Wh/kg, respectively. The cyclic stability is confirmed by the observed constant values of power and energy densities for different cycles. [ABSTRACT FROM AUTHOR]

The control of dielectric permittivity and conductivity is a crucial factor in the development of certain electronic components. Materials based on layered structures and polyvinyl alcohol (PVA) show great potential for applications in supercapacitors. Therefore, the creation of polymer composites based on layered semiconductors and the determination of their physical properties is significant. In this investigation, a composite comprising 1 wt% FeGaInS4 dispersed in PVA was synthesized through mechanical mixing, where the FeGaInS4 crystal was incorporated into the PVA matrix. This study explores the physical characteristics of this composite for the first time. The structure of the composite was analyzed using x‐ray diffraction (XRD). Electrical properties and conductivity mechanisms were examined using a dielectric spectrometer. It was determined that the hopping model conductivity mechanism predominates in the FeGaInS4/PVA nanocomposite. For the 1 wt% FeGaInS4/PVA composite, system parameters were calculated at a temperature of 313 K and a frequency of 5 × 103 Hz. The parameters found are s = 0.814, potential barrier height WM = 0.868 eV, hopping length Rω = 14.7 × 10−10 m, and the concentration of pairs of states between, which charge carriers hop N = 1.396 × 1026 m−3. Highlights: 1 wt% FeGaInS4 composite synthesized via mechanical assembly.Small crystals boost dielectric constant by 1.5× via interfacial polarization.The system parameters are defined: s = 0.814, WM = 0.868 eV, Rω = 14.7 × 10−10 m.Electrical conduction is multifaceted; conductance hopping dominates.Loss tangent decreases due to interfacial polarization effects. [ABSTRACT FROM AUTHOR]

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This study establishes a comprehensive correlation among structural, electrical, and dielectric analyses of fluorine-doped tin oxide (FTO) nanoparticles. The nanoparticles were synthesized through the modified sol–gel method under ethyl supercritical conditions. The investigation into the electrical transport, influenced by the microstructure and grain size of FTO nanoparticles, prompted an exploration of charge carrier transport mechanisms and the impact of doping on this behavior. Both structural and electrical analyses were performed on the samples. The x-ray diffraction results reveal a tetragonal rutile structure in the nanoparticles, as validated by Raman analysis. Particle size and strain values were determined using the Williamson–Hall method, complemented by morphological observations using transmission electron microscopy images. Electrical studies revealed semiconducting behavior in all samples, with conductivity analyzed using Jonscher's law. The small polaron hopping and correlated barrier hopping process models are appropriate for describing the conduction process in the prepared sample. The observed behaviors of the imaginary components of impedance (Z″) and modulus (M″) signify a dielectric relaxation phenomenon within the sample, with activation energies closely matching those derived from the conductivity study. The results strongly suggest that our samples hold great promise for future electronic device applications. [ABSTRACT FROM AUTHOR]

A bottleneck characterized by high strain and low hysteresis has constantly existed in the design process of piezoelectric actuators. In order to solve the problem that actuator materials cannot simultaneously exhibit large strain and low hysteresis under relatively high electric fields, Nb5+-doped 0.975(Ba0.85Ca0.15)[(Zr0.1Ti0.9)0.999Nb0.001]O3-0.025(Bi0.5Na0.5)ZrO3 (BCZTNb0.001-0.025BiNZ) ceramic thick films were prepared by a film scraping process combined with a solid-state twin crystal method, and the influence of sintering temperature was studied systematically. All BCZTNb0.001-0.025BiNZ ceramic thick films sintered at different sintering temperatures have a pure perovskite structure with multiphase coexistence, dense microstructure and typical dielectric relaxation behavior. The conduction mechanism of all samples at high temperatures is dominated by oxygen vacancies confirmed by linear fitting using the Arrhenius law. As the sintering temperature elevates, the grain size increases, inducing the improvement of dielectric, ferroelectric and field-induced strain performance. The 1325 °C sintered BCZTNb0.001-0.025BiNZ ceramic thick film has the lowest hysteresis (1.34%) and relatively large unipolar strain (0.104%) at 60 kV/cm, showing relatively large strain and nearly zero strain hysteresis compared with most previously reported lead-free piezoelectric ceramics and presenting favorable application prospects in the actuator field. [ABSTRACT FROM AUTHOR]

The conductivity and electric modulus formalism in tellurite-modified lithium borate glasses with composition (100–x) − (33.35Li2O–66.65B2O3) − (x)TeO2, (x = 0, 5, 10, 15, 20 and 25 mol%) have been prepared. Electric modulus, relaxation mechanism and conductivity parameters were investigated to understand the dielectric properties of the glass matrix in the temperature range between 403 and 583 K, and the frequency range between 100 Hz and 5 MHz. The experimental data of ac conductivity was fitted to Jonscher’s power law. The parameters like dc conductivity (σdc), frequency exponent (S) and crossover frequency (WH) were extracted. The conductivity of the glass matrix was found to exhibit anomalous increasing behaviour with TeO2 content. The decreasing trend in the values of the frequency exponent with the temperature rise demonstrates the correlated barrier hopping mechanism in the conduction process. The electric modulus data fitted to Davidson–Cole model and Kohlrausch–Williams–Watts model have revealed nearly the same values of β (Kohlrausch exponent), which depict the conductivity relaxation process. Other electrical parameters such as bulk resistance (Rb), capacitance (Ao) and stretching exponent (n) were also extracted by fitting the impedance data to the R-CPE model using Zview software. The dc conductivity of lithium boro tellurite glasses was found to follow Arrhenius behaviour and the corresponding activation energy was determined (0.5847–1.0004 eV). [ABSTRACT FROM AUTHOR]

This study explores the conduction mechanism of NbTe4, a novel phase-change material (PCM) for phase-change random access memory (PCRAM), and addresses the limitations of the widely used Ge2Sb2Te5 (GST). Unlike traditional PCMs, NbTe4 in its amorphous state demonstrates low resistance, which indicates semiconductor behavior. However, the Hall and Seebeck coefficient measurements reveal an intriguing anomaly--amorphous NbTe4 displays N-type conduction with Hall voltage and P-type conduction in the positive Seebeck coefficient. This Hall effect anomaly, which is typically associated with highly resistive chalcogenide materials, raises questions about the conduction mechanism in amorphous NbTe4. This study delves into the electrical transport properties of NbTe4 and provides insights into the unique characteristics of this PCM. [ABSTRACT FROM AUTHOR]

In this study, Ba0.6Sr0.4Ti1-xMnxO3 ceramics were fabricated by a novel ball milling technique followed by spin-coating to produce thin-film resistive memories. Measurements were made using field emission scanning electron microscopes, atomic force microscopes, X-ray diffractometers, and precision power meters to observe, analyze, and calculate surface microstructures, roughness, crystalline phases, half-height widths, and memory characteristics. Firstly, the effect of different sintering methods with different substitution ratios of Mn4+ for Ti4+ was studied. The surface microstructural changes of the films prepared by the one-time sintering method were compared with those of the solid-state reaction method, and the effects of substituting a small amount of Ti4+ with Mn4+ on the physical properties were analyzed. Finally, the optimal parameters obtained in the first part of the experiment were used for the fabrication of the thin-film resistive memory devices. The voltage and current characteristics, continuous operation times, conduction mechanisms, activation energies, and hopping distances of two types of thin-film resistive memory devices, BST and BSTM, were measured and studied under different compliance currents. [ABSTRACT FROM AUTHOR]

Radiation-hardness of silicon (Si) has been the subject of interest due to the damage of the material-based detectors during and after operation. In this work, the effects of 4 MeV proton-irradiation on the electrical properties of devices fabricated on undoped and Fe-doped p-Si were investigated using current-voltage (I-V) and capacitance-voltage (C-V) techniques. A decrease in current and capacitance is less pronounced and the conduction mechanism remains unchanged on Fe-doped p-Si diode after proton-irradiation. This insignificant change of electrical parameters of the Fe-doped diode after proton-irradiation indicates the suppression of the radiation effect by Fe in Si. The electrical properties of the diode are less dependent on incident radiation, because of the possible prevention of further dislodgement of atoms by incident radiation. As a result, the material becomes resistant to radiation damage, making the electrical properties of the diode independent of incident radiation due to Fe atoms in Si. As a result of the ohmic behaviour displayed by the Fe-doped Si diode, it is possible that in Si, Fe is responsible for generation-recombination (g-r) centres, which are defect levels positioned at the middle of the energy gap of Si. The possibility of these defects being responsible for the suppression of the radiation effect is explained in this work, making Fe a promising dopant to improve the radiation-hardness of Si. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membranes (PEMs) play a vital role in electrochemical devices, facilitating ion conduction while blocking gases and electrons. Their effectiveness is closely linked to their microstructural properties, especially the free volume, which impacts ionic conductivity, mechanical strength, and overall device performance. This study examines the behavior of PVC/PMMA/SSA blends under electric fields, using Positron Annihilation Lifetime Spectroscopy (PALS) to assess free volume and dielectric properties. The study involved preparing and characterizing membranes through x‐ray diffraction (XRD), thermogravimetric analysis (TGA), and PALS. XRD results indicated semi‐crystalline structures with changes in intensity due to temperature variations, while TGA highlighted changes in thermal stability under different electric fields. PALS measurements showed that free volume varied with temperature and electric field strength, influencing the material's dielectric and mechanical characteristics. The results revealed that higher electric fields reduced free volume while enhancing dielectric properties. The dielectric constant and loss were found to depend on frequency, which was affected by the polar SO3H groups. Impedance spectroscopy provided further insights into the electrical properties, showing increased dc conductivity with stronger electric fields. A correlation between the free volume investigated from PAL and the electrical properties was observed. This study emphasizes the significance of free volume and external electric field in optimizing PEMs for advanced energy applications. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of lithium diphosphate compound LiCeP2O7 via conventional solid-state reaction. Analysis using the Rietveld refinement of the X-ray diffraction pattern reveals that the sample adopts a monoclinic structure at room temperature. Surface morphology is further examined through SEM. Additionally, complex impedance and electrical modulus spectroscopy analyses indicate the presence of non-Debye-type relaxation behavior. The direct current (dc) conductivity exhibits Arrhenius behavior, with activation energies of 0.94 eV in region I and 1.21 eV in region II, indicating thermally activated lithium-ion conduction. The thermal behavior of the exponent parameter "s" suggests a transition in the conduction mechanism from large polaron tunneling to small polaron tunneling that occurs at 533 K. Electric modulus studies confirm that the ionic conduction relaxation process is thermally activated and exhibits a spread of relaxation time. Understanding the ionic conduction mechanism will facilitate the design of efficient ionic conductors for battery applications. [ABSTRACT FROM AUTHOR]

Using the solution casting procedure, poly (vinyl alcohol)/carboxymethyl cellulose/polypyrene/milled multiwall carbon nanotubes, PVA/CMC/PPy/x wt% milled MWCNTs blended polymers were formed. X-ray diffraction and scanning electron microscopy were employed to inspect the structure and morphology of the resulted blends. The lowest direct and indirect optical band gaps are (5, 4.3) eV and (4.37, 3.38) eV, respectively, achieved when the MWCNTs content in the doped blend was 0.25 wt %. By incorporating varying quantities of milled MWCNTs into the PVA/CMC/PPy blended polymer, consistent enhancements were observed in the optical dielectric constant and optical conductivity values. The blend with 0.25 wt% MWCNTs exhibited the maximum values of refractive index. The maximum electric dielectric constant and energy density values were attained as x = 0.15. The temperature impacted the dielectric constants and energy storage values. All blends fit with the CBH model. The impact of MWCNTs doping level and the temperature on the impedance spectroscopy and electric modulus of the host blend was explored. The sample with x = 0.15 has the smallest relaxation time. The impact of MWCNTs doping level on the dc conductivity, activation energy and conductivity mechanism of the host blend was explored. The doped blends with x = 0.15 is viable materials for energy storage purposes.

Herein, we report on the post-annealing temperature effect on the transport behavior of p-CuO/Al Schottky barrier diodes. In addition, the transformation of phase from Cu4O3 to CuO phase was studied. Copper oxide thin films were grown on soda lime glass substrates, and post-annealing temperature's influence on the films' structural, chemical, morphological, and electrical characteristics was comprehensively examined. X-ray diffraction study revealed the development of polycrystalline tenorite phase (CuO) on annealing. Raman analysis also confirmed the formation of the tenorite phase (CuO) at higher annealing temperatures (400 °C and 500 °C). XPS study revealed the occurrence of the Cu4O3 phase for room temperature deposited sample and CuO phase at the higher annealing temperature. Using current–voltage analysis, the Chueng model, and the thermoelectric emission model, the Schottky behavior between the metal and semiconductor were investigated. The fabricated diode showed a rectification ratio of 103 at ± 2 V, with the barrier height ranging from 0.84 to 1.12 eV due to different annealing treatments. The attributes of the power law were employed to elucidate space charge-limited conduction and the process of tunneling across the density of interface traps in p-CuO/Al Schottky diodes. This study provides valuable insights into the behavior of the p-CuO/Al Schottky junction, enhancing our understanding of its characteristics. [ABSTRACT FROM AUTHOR]

In China, urbanization is mainly stimulated by resource flows, and industrialization is normally accompanied by an increase in the proportion of the urban population and urban land area. During the process, urbanization at a rapid pace often induces a huge consumption of energy and environmental emissions. Nevertheless, it is also worth considering whether urbanization positively affects urban environment promotion. With a more solid economic foundation, urban subjects will carry out energy conservation and emission reduction (ECER) from various aspects, primarily focusing on technological innovation, advancement of production mechanisms and structural optimization. Along these lines, this study aims to examine urbanization's direct and indirect impact on energy conservation and emission reduction using panel data consisting of 196 Chinese cities for the period of 2011–2018 with a Slacks-based model and transmission mechanism. Study results indicate that urbanization's development can give a direct impetus to ECER, which is quite robust after employing a series of robust tests, including instrumental variable estimation. Besides, urbanization indirectly influences ECER by promoting economic growth, better allocation of resources, internet advancement, and adjusting the employment structure. Further investigation suggests that the relationship between urbanization and ECER is nonlinear, depending on the levels of the above-mentioned mediating variables. Finally, essential policy suggestions are proposed, i.e. promoting high-quality development of urban clusters, accelerating the policies for ECER, and paying more attention to economic growth, resource allocation, internet technology, and employment structure. [ABSTRACT FROM AUTHOR]

In recent years, railway safety accidents have repeatedly occurred. Any omission in the process of management or operation can easily have very serious consequences. This study aimed to examine the causes and transmission mechanisms of safety risks in railway engineering departments. First, the multi-objective particle swarm optimization algorithm was employed to determine the key risk factors, allowing for indicator screening that was in line with the requirements of practical applications. Then, Bayesian networks were used, and their structure was optimized to analyze the propagation diagnosis and probability of key risk indicators, obtaining the causal logic chain that produces accidents and, from that, the four aspects (human, machine, environment, management) of the corresponding prevention of risk recommendations. Finally, in this article, it is shown that combining the indicators and Bayesian networks can improve the accuracy of risk prediction and provide more accurate results than using existing research and, hence, it can fill the gap in research on railway safety risks in risk transmission mechanisms. [ABSTRACT FROM AUTHOR]

BaTiO3‐based compounds are recognized as the most common dielectric material used in multilayer ceramic capacitors (MLCCs), among which, BaTiO3‐BiMeO3 is extensively investigated to improve the thermal stability and extend the service life of MLCCs, which are strongly dependent on the conductivity at high temperatures. Despite numerous efforts have been made, the mechanism of oxygen vacancy conduction, which makes the major contributions to the conduction mechanism of BaTiO3‐based compounds at high temperatures below 450°C, is still unclear. In this paper, BaTiO3, 0.88BaTiO3‐0.12Bi(Zn2/3Nb1/3)O3, 0.88BaTiO3‐0.12Bi(Mg2/3Nb1/3)O3, and 0.88BaTiO3‐0.12Bi(Mg2/3Ta1/3)O3 ceramics have been prepared by solid‐state reaction method, and their electrical and dielectric properties have been studied in detail. Meanwhile, first principles were applied to study the mechanisms of the increase of electrical resistivity and the decrease of dielectric loss. It is found that B‐site dopants (Zn, Mg, Nb, and Ta) are effective in reducing the conductivity by inhibiting the migration of oxygen vacancies, which is a kinetics process with an increase of energy barrier. Notably, the greater ability of Zn to inhibit oxygen vacancies migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (an effect of block the migrating defects in the lattice). This work reveals a new insight into the mechanism of oxygen vacancies migration in BaTiO3‐based perovskite compounds, which makes BaTiO3‐BiMeO3 prospective in designing efficient and durable medium‐temperature solid oxide capacitor devices. [ABSTRACT FROM AUTHOR]

Solid-state polymer electrolyte system that relies on an Iota carrageenan/Acacia gum blend and ethylene glycol as plasticizer incorporated with LiNO3 has been synthesized using the solution cast technique. The structural characterization has done by X-ray diffraction and Fourier transform infrared (FTIR) analysis. FTIR deconvolution reveals that ion–ion interaction analysis and the free ion and contact ion percentage. The electrolyte with 30 wt% LiNO3 (IAN30) has the higher conductivity as 1.77 × 10−3 S cm−1, activation energy as 0.02 eV and ion transport number as 0.999. The non-Debye property of polymer electrolytes is confirmed by studies on the frequency dependence of dielectric and, dielectric loss tangent parameter β. UV spectra of IAN30 also confirms the reduction in band-gap. IAN30 is used for the fabrication of Electric double layer capacitor (EDLC) and Electrochemical cell. There are no redox peaks in the Cyclic voltammetry response through its entire potential range for EDLC behavior. From the galvanostatic charge/discharge studies of prepared symmetrical capacitor, discharge time and specific capacitance (Cs) values are calculated as 16s and 22 F/g respectively. [ABSTRACT FROM AUTHOR]

In this study, Ba0.6Sr0.4Ti1-xMnxO3 ceramics were fabricated by a novel ball milling technique followed by spin-coating to produce thin-film resistive memories. Measurements were made using field emission scanning electron microscopes, atomic force microscopes, X-ray diffractometers, and precision power meters to observe, analyze, and calculate surface microstructures, roughness, crystalline phases, half-height widths, and memory characteristics. Firstly, the effect of different sintering methods with different substitution ratios of Mn4+ for Ti4+ was studied. The surface microstructural changes of the films prepared by the one-time sintering method were compared with those of the solid-state reaction method, and the effects of substituting a small amount of Ti4+ with Mn4+ on the physical properties were analyzed. Finally, the optimal parameters obtained in the first part of the experiment were used for the fabrication of the thin-film resistive memory devices. The voltage and current characteristics, continuous operation times, conduction mechanisms, activation energies, and hopping distances of two types of thin-film resistive memory devices, BST and BSTM, were measured and studied under different compliance currents.

BiFeO3–BaTiO3 (BF–BT) based piezoelectric ceramics are a kind of high-temperature lead-free piezoelectric ceramics with great development prospects due to their high Curie temperature (TC) and excellent electrical properties. However, large leakage current limits their performance improvement and practical applications. In this work, direct current (DC) test, alternating current (AC) impedance, and Hall tests were used to investigate conduction mechanisms of 0.75BiFeO3–0.25BaTiO3 ceramics over a wide temperature range. In the range of room temperature (RT)−150 ℃, ohmic conduction plays a predominant effect, and the main carriers are p-type holes with the activation energy (Ea) of 0.51 eV. When T > 200 ℃, the Ea value calculated from the AC impedance and Hall data is 1.03 eV with oxygen vacancies as a cause of high conductivity. The diffusion behavior of thermally activated oxygen vacancies is affected by crystal symmetry, oxygen vacancy concentration, and distribution, dominating internal conduction mechanism. Deciphering the conduction mechanisms over the three temperature ranges would pave the way for further improving the insulation and electrical properties of BiFeO3–BaTiO3 ceramics.

This paper investigates the bismuth ions leverage on magnetic and dielectric features of magnesium–copper nanoferrites Mg0.5Cu0.5BixFe2-xO4 (MCBF). The Mg0.5Cu0.5Bi0.1Fe1.9O4 nanoferrite exhibits superior magnetic properties compared to the pure Mg-Cu sample. These properties include a higher magnetization of 31.31 emu/g, with an enhancing ratio of 1.50 %. Additionally, it demonstrates a higher initial permeability of 17.84, with an enhancing ratio of 55.12 %. Furthermore, their coercivity is lower at 59.90 Oe, with an enhancing ratio of 50 %. All MCBF nanoferrites exhibit a high-frequency response between 6.106 and 6.926 GHz, making them suitable for microwave technology. The dielectric parameters dispersion shows normal behavior at different frequencies and temperatures. As for dielectric parameters dependence on Bi content, it exhibited a peculiar manner. At a temperature of 297 K and a frequency of 50 Hz, the nanoferrite Mg0.5Cu0.5Bi0.1Fe1.9O4 exhibits superior dielectric properties compared to the pure Mg-Cu sample. Specifically, it demonstrates the highest dielectric constant of 360.68, with an enhancing ratio of 125.97 %. Additionally, it displays the highest conductivity of 691.4 µ(Ω.m)-1, with an enhancing ratio of 1543.23 %. Furthermore, the nanoferrite exhibits a lower dielectric loss of 6.49, with an enhancing ratio of 80.22 % compared to the pure Mg-Cu sample. The conduction mechanism of the Mg0.5Cu0.5BixFe2-xO4 nanoferrites was determined by fitting the σac results via the Jonscher power law. This conduction mechanism is attributed to correlated barrier hopping (CBH) model up to 473 K, followed by small polaron tunneling (SPT), which reaches higher temperatures. Hence, the Mg0.5Cu0.5Bi0.1Fe1.9O4 nanoferrite has a remarkable magnetic and dielectric nature, which can be used as functional soft ferrite material in transformers and high-frequency electronic devices.

Geomorphic clinoptilolite, a mechanically and thermally stable mineral substance, has very useful electrical properties due to the presence of extra-framework cations in the crystal structure. Indeed, owing to the electrical transport that alkaline earth metal cations may give, this ceramic material behaves like an electrical insulator at room temperature, while it changes to an electrical conductor with increasing of temperature. Such unusual electrical property of clinoptilolite can be advantageously exploited for a number of functional applications in industrial fields. For example, clinoptilolite-based devices can be used as thermal sensors, electrical/thermal switches, NTC thermistors, etc. Here, the capability of a simple natural clinoptilolite monolith to switch from an electrical insulator to a conductor under fast temperature changes has been investigated via time-resolved a.c. electrical transport measurements. [ABSTRACT FROM AUTHOR]

In this study, calcium titanate (CaTiO3) doped (0, 15, 25 and 35%) polyaniline (PANI) composites in the presence of dodecylbenzene sulphonic acid (DBSA) were successfully synthesized by the means of in-situ emulsion polymerization of aniline monomer. The structural, morphological and optical characterization of as-prepared composites were determined using X-ray diffraction (XRD), field effect scanning electron microscopy, Fourier-transform infrared spectroscopy, UV–vis analysis, and electronic conductivity was determined using two-point probe method. The structural analysis confirms that PANI–DBSA is amorphous, but sharp peaks present in XRD patterns in composites are of crystalline nature. The morphological study reveals efficacious integration of CaTiO3 particles into the PANI–DBSA matrix. Further, the integration of CaTiO3 remarkably reduced the optical bandgap (2.7–2.2 eV) by making composites with PANI–DBSA. Room temperature alternating current conductivity was found to obey universal power law and correlated barrier hopping was found most appropriate model to describe the sample's charge transport mechanism. With the increasing wt% of CaTiO3, the dielectric permittivity and loss both varied according to the interfacial polarization law of Maxwell–Wagner. Moreover, the I–V graphs showed augmented electrical conductivity of composites with an increase in CaTiO3 particle content than that of pure PANI–DBSA. This is a simple way by which PANI–DBSA/CaTiO3 composites having low optical bandgap, high electrical conductivity and permittivity may be fabricated for a widespread technological application. [ABSTRACT FROM AUTHOR]

The effects of Fe-implantation on the electrical characteristics of Au/p-Si Schottky barrier diodes (SBDs) were studied using current–voltage (I–V) and capacitance–voltage (C–V) techniques. The Rutherford Backscattering Spectrometry (RBS) and Energy Dispersive Spectroscopy (EDS) results showed that Fe ions are well implanted and present in the Fe-implanted Si material. The acquired results from I–V and C–V analysis showed that the diodes were well fabricated, and Fe-implantation changed the normal diode’s I–V behaviour from typical exponential to ohmic. The ohmic behaviour was described in terms of the defect levels induced by Fe in the middle of the band gap of Si. The conduction mechanism for both forward and reverse currents was presented, and the effect of Fe-implantation on the conduction mechanisms was investigated. The C–V results show that Fe generates a high density of minority carriers in p-Si, which agreed with the increase in reverse current observed in the I–V results. The diode parameters in terms of saturation current, ideality factor, Schottky barrier height, doping density, and space charge region (SCR) width were used to investigate the effect of Fe in p-Si based diode. Owing to the observed changes, which were analogous to those induced by dopants that improve the radiation hardness of silicon, it was safe to say that Fe can also assist in the quest to improve the radiation hardness of silicon using the defect-engineering method.

Magnetoelectric (ME) composites (x) Ni0.6Mg0.4Fe2O4) + (1-x) (BaZr0.2Ti0.8O3) were synthesized by using solid state reaction technique, followed by uniaxial pressing and sintering process at 1150 °C. Effects of ferrite/ferroelectric composition on structural, electric and magnetic properties were studied. XRD analysis revealed the synthesized composites containing ferrite and ferroelectric phases without any impurity phase. The variation of DC electrical resistivity with respect to temperature revealed the semiconducting behaviour. Dielectric properties were confirmed the conduction mechanism of the composites. By changing ferrite content in composites, the magnetic anisotropy of ferrite phase has been tuned up and studied its role on ME response of the composites. It is observed that the magnetic parameters such as saturation magnetization, magnetic moment and coercivity are found to be decreases with increasing ferrite concentration in composites. Also, it is observed that the sample x = 0.1 has the largest value of saturation magnetization (14.035emu/gm), while sample x = 0.3 shows the lowest value (7.204emu/gm). We interpreted the results in the framework of dynamic piezomagnetic coefficient and also cation distribution in the spinel structure of ferrite phase.

In this study, we investigated the effects of Zn doping on electrical properties and conduction mechanisms of n-silicon (n-Si) diodes using current-voltage (I–V) and capacitance-voltage-frequency (C–V–f) measurements. The results revealed that Zn doping alters the I–V behaviour of the diode from a typical exponential curve to an ohmic one. Notably, Zn doping increased the reverse current by a factor of 37, while reducing the forward current by a factor of 3 at 3 V. This suggested that Zn-related defects introduced more minority carriers into the Si. The introduction of minority carriers is confirmed by a change in material conductivity-type from n-to p-type. Moreover, Zn doping reduces the full depletion voltage (FDV), meaning the diode could be fully depleted with a lower voltage. This reduction in FDV was crucial for designing highly sensitive radiation detectors. The observed changes in the diode's electrical behaviour were attributed to defects introduced by Zn into Si. Zn-doped n-Si diodes exhibited characteristics akin to radiation-resistant diodes. These findings implied that Zn may be instrumental in advancing research focused on enhancing silicon properties and developing radiation-resistant detectors for high-energy physics studies.

A simple hydrothermal technique and in-situ chemical oxidative polymerization of pyrrole monomer yield the functionalized NiO@C@PPy nanomaterial for electromagnetic shielding applications. The crystal structure, morphology, dielectric and electromagnetic shielding (EMI) performance in the X-band (8.2–12.4 GHz) is thoroughly studied. Impedance spectroscopy is utilized to study the electrical response of a NiO@C@PPy pellet. This study focuses on the modulations of relaxation time with frequency at different temperatures. In the NiO@C@PPy composite, a semiconductor-to-metal transition (SMT) is observed, at 328 K. The conduction mechanism of NiO@C@PPy is explained based on the carrier hopping transport model in Ni2+ and Ni3+ ions. It is evident from the activation energy value (Ea ≈ 0.32 eV) determined from impedance, conductivity, and dielectric data that the relaxation and conduction processes correspond to the same electro-active region. Using the variable range hopping (VRH) model localization length of the carrier is calculated to be 1.56 Å. The NiO@C@PPy sample demonstrated enhanced conductivity and low dielectric values which are vital in EMI shielding applications. Consequently, the electromagnetic interference shielding effectiveness is found to be 21.9 dB of NiO@C@PPy in the X-band frequency range. This composite material is a good candidate for high frequency shielding applications.

For high temperature thermistor applications, the MgAl 2 O 4 exhibits poor conductivity and requires high sintering temperature for ceramic densification. In this study, we have reported on the preparation and characterization of spinel Mg 0.5 Mn 0.5 AlFeO 4 ceramics by solid solution modification. The resultant ceramics exhibit a combination of high temperature stability and semi-conductivity, which are the characteristics of MgAl 2 O 4 and MnFe 2 O 4. The material has a moderate thermistor constant, which is in favor of application at high temperatures and a wide temperature range. The electrical conductivity is due to the small-polaron hopping in different valence states of manganese and iron ions. Our findings demonstrate a promising approach to extend the applicability of spinel ceramics for high temperature thermistors. [ABSTRACT FROM AUTHOR]

The effect of Sr2+ doping on electrical conductivity and dielectric constant was studied in Y2 − xSrxNiMnO6 (YSNMO). Rietveld refinement of XRD data showed the coexistence of monoclinic (P21/n) and rhombohedral (R ) as major and minor phases, respectively. Impedance analysis of YSNMO was performed to investigate the presence of various electro-active regions, electrical conduction mechanisms and the origin of the colossal dielectric constant in wide temperature (83-303 K) and frequency (40 Hz-6 MHz) ranges. An equivalent circuit model (RgCg)(RgbQgb)(ReQe) has been proposed to correlate the electrical properties. The Rg and Rgb obtained using ZView fitting revealed the semiconducting nature of the sample. The transition in the conduction mechanism from variable range hopping to small polaronic hopping was observed at about 213 K. DC bias measurements, which followed the Mott-Schottky law, confirmed the existence of non-Ohmic electrode contact. The dielectric spectra of ceramic were described using the modified Cole-Cole equation. The frequency dependent ac conductivity was investigated with the Jonscher's power law. [ABSTRACT FROM AUTHOR]

Perovskite oxide BaNi0.5Mn0.25Fe0.25O3 was successfully synthesized using a sol–gel method. Structural refinement analysis has been performed to investigate the details of the crystalline structure which was found to be a rhombohedral system at room temperature with the space group R 3 ¯ C . Crystallite size, lattice strain, density and porosity parameters were also calculated. The morphology and the elemental composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Raman scattering spectroscopy has been performed in order to study the vibrational modes and the various bond formations of the synthesized sample. The study of the magnetic properties shows a ferro-paramagnetic transition (FM–PM) at the curie temperature. The electrical behavior of this double perovskite was also studied using complex impedance spectroscopy. Electrical conduction follows Jonscher's power law, and the conduction mechanisms are identified. The variations of the real and imaginary parts of impedance according to the frequency and temperature show the presence of a relaxation phenomenon in the sample, and it is thus a potential candidate for various technological applications in microelectronics and energy storage. [ABSTRACT FROM AUTHOR]

Resistive random access memory (RRAM) has lots of advantages that make it a promising candidate for ultra-high-density memory applications and neuromorphic computing. However, challenges such as high forming voltage, low endurance, and poor uniformity have hampered the development and application of RRAM. To improve the uniformity of the resistive memory, this paper systematically investigates the HfOx-based RRAM by embedding nanoparticles. In this paper, the HfOx-Based RRAM with and without tungsten nanoparticles (W NPs) is fabricated by magnetron sputtering, UV lithography, and stripping. Comparing the various resistive switching behaviors of the two devices, it can be observed that the W NPs device exhibits lower switching voltage (including a 69.87% reduction in Vforming and a reduction in Vset/Vreset from 1.4 V/-1.36 to 0.7 V/-1.0 V), more stable cycling endurance (>105 cycles), and higher uniformity. A potential switching mechanism is considered based on the XPS analysis and the research on the fitting of HRS and LRS: Embedding W NPs can improve the device performance by inducing and controlling the conductive filaments (CFs) size and paths. This thesis has implications for the performance enhancement and development of resistive memory. [ABSTRACT FROM AUTHOR]

A better reconciliation of haze pollution and economic growth has become the social consensus in China. The development of China's economy and air quality will be significantly impacted by its efforts to create high-speed rail (HSR). Based on panel data from 265 prefecture-level cities in China from 2003 to 2019, this paper investigates how the opening of HSR affects the spatial mismatch of haze pollution and economic growth by using the spatial mismatch index model, multi-period difference-in-differences (DID) model, and intermediary effect model. We find that the spatial mismatch in China has an overall decreasing trend. And its spatial agglomeration is dominated by low levels. Further empirical analysis shows that HSR opening can effectively restrain the spatial mismatch. Even after some robustness tests and endogenous treatment, the conclusion is still valid. In addition, population density, FDI, and industrial structure are also explicit factors affecting the spatial mismatch. Second, there is significant heterogeneity in the impact. This is reflected in the fact that HSR opening can suppress the spatial mismatch of service-oriented cities and the eastern region, while other cities and regions have no noticeable effect. Third, spatial transfer of haze pollution (STHP) and balanced development of economic growth (BEG) are two important conduction paths for the opening of HSR to affect the spatial mismatch. Specifically, HSR opening can constrain the spatial mismatch by inhibiting STHP and BEG. Based on the above findings, recommendations related to promoting a better harmony between haze pollution and economic growth are proposed. [ABSTRACT FROM AUTHOR]