AC Electrical Properties Research Articles

AC Electrical Property and Generation of Extra Eddy Current Loss of Mn-Zn Ferrites at High Frequency

AC Electrical Property and Generation of Extra Eddy Current Loss of Mn-Zn Ferrites at High Frequency

Synthesizing, characterizing, and cold plasma treating of Cr2O3/CuO nanomaterials doped PMMA/PEO for flexible optoelectronic applications

Polymeric nanocomposites are attracting significant attention due to their ability to facilitate innovative uses. This work investigated the possibility of improving performance by examining the impact of dispersing copper oxide (CuO) and chromium (III) oxide (Cr2O3) nanoparticles in a blend of poly (methyl methacrylate) and polyethylene oxide (PEO) on several properties. UV–visible and photoluminescence spectroscopies were used for optical properties, and FE-SEM was used for surface morphology analysis. The results showed that as the CuO–Cr2O3 percentage increased, the extinction coefficient increased, and indirect band gaps decreased. The photoluminescence properties showed two distinct peaks (dual emission). We measured the AC electrical properties with frequencies ranging from 100 Hz to 5 MHz. The composite's AC conductivity and dielectric loss increased significantly at high frequencies (higher than 2 MHz). The dielectric constant is nearly frequency-independent and increases as the concentration of nanoparticles increases. We used a DC plasma sputtering facility to treat the nanocomposites with argon plasma at a pressure of 0.12 mBar for 7 min. We analyzed the films' properties before and after plasma treatment, observing a significant impact on nanocomposite-incorporated nanoparticles. After plasma treatment, the band gap decreased from 5.05 eV to 4.8 eV for the lowest concentration of CuO + Cr2O3 (1.5 wt%) and from 3.55 eV to 2.47 eV for the highest concentration of CuO + Cr2O3 (6 wt%). The changes ranged from 0.25 to 1.08 eV. The films possess features that render them suitable for high-frequency optoelectronic devices as well as optical applications such as emission filters and UV shielding.

Tuning structural and electrical properties of Co-precipitated and Cu-incorporated nickel ferrite for energy applications

Abstract The Ni1−x Cu x Fe2O4 (where x = 0, 0.05, 0.10, 0.15) nano ferrite powder was synthesized through chemical co-precipitation method, NaOH and acid oleic as raw materials. The XRD patterns confirmed the spinal structure phase purity of materials. XRD results showed that lattice parameter decreases with the increase of copper concentration by increasing copper concentration in the parent material. Scanning electron microscopy (SEM) was used to determine the morphology and particle size. SEM analysis indicated that all the samples are in nano size and homogeneous. AC electrical properties of nanoparticles were investigated by employing impedance spectroscopy. The real and the imaginary parts of impedance, permittivity, modulus along with the real part of ac conductivity, and tan delta were measured and analyzed for all synthesized samples in 1 Hz to 7 MHz for different voltages at 300 K.

Synthesis and dielectric properties of polyvinyl chloride/zinc oxide nanocomposites

AbstractBecause of its special structural and functional characteristics, poly(vinyl chloride)/zinc oxide nanocomposite (PVC/ZnO) exhibits great potential in a variety of electrical, optical, water treatment, and medical applications. According to that, this study was carried out to examine the AC electrical properties of the prepared PVC/ZnO nanocomposite films using the AC impedance techniques. The PVC/ZnO nanocomposite films were prepared by casting method by weight% concentrations of 2.5, 5.0, 7.5 and 10.0% ZnO nanoparticle. Each mixture was fabricated in film and casted in 5 cm × 5 cm glass caste. Fourier transform infrared (FTIR) spectroscopy, x‐ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the nanocomposites samples. The results of the FTIR spectroscopy analysis of the PVC/ZnO nanocomposites confirmed the presence of peaks characteristic of the vibration of the ZnO bond. XRD revealed that pure PVC films are partially crystalline with hallow peak but ZnO nanoparticles have wurtzite structure, and the nanocomposite films were almost the same as those of ZnO with decrease in the degree of crystallization, causing increase in the amorphous region. The surface of the films was analyzed by SEM, which becomes rough with some small aggregates compared with pure PVC with good distribution in the entire surface region with bright spots. The electrical properties AC conductivity (), real dielectric constant (), imaginary dielectric constant (), real electrical modulus (), and imaginary electric modulus () were studied in the frequency range 2–6 MHz and temperature range 293–313 K for the prepared film studied. The results showed that the properties of the PVC/ZnO nanocomposite films were found to be dependent on the frequency, and the concentration of the ZnO nanoparticle in the PVC polymer matrix. In addition, the results of the study show that there is a sharp increase in the , with increasing of temperature. In contrast, the other parameters, that is, , , , and are temperature independence.Highlights PVC/ZnO nanocomposite films with different weight% concentrations of ZnO nanoparticle were prepared. AC electrical properties were measured using AC impedance techniques. The nanocomposites samples were characterized using FTIR, XRD, and SEM. Electrical properties , , , , and were found to be frequency and temperature dependences.

Structural, morphological, elastic, optical and electrical properties of MgO nanostructures

The magnesium oxide (MgO) nanoparticles were synthesised by solution combustion method. XRD results confirm the nanophase (crystallite size ∼30 nm) of a prepared sample with cubic structure. Mechanical stability assessments indicated excellent elastic moduli, highlighting the brittle nature of a material. Scanning Electron Microscopy (SEM) revealed the agglomerated and porous morphology of the MgO nanoparticles. UV–Visible characterization reveals an absorption peak at 295 nm, corresponding to an optical band gap of 3.6 eV. Photoluminescence spectroscopy identifies emission peaks at 406 nm, 436 nm, and 450 nm attributed to various structural defects. The frequency and temperature dependence on AC electrical properties were investigated at varying temperature (27oC–250oC) and frequency (50 Hz-5 MHz). The electrical modulus and Cole-Cole plots reveal relaxational behaviour and changes in the material's stiffness with temperature. From the obtained results it is evident that the synthesised MgO nanoparticles are suitable for electronic device applications.

Influence of design and annealing parameters on measurements of AC properties of NiFe-SiO2 multilayer structures

In this article, due to the exceptionally interesting electrical and magnetic properties of nanocomposites, which include ferromagnetic materials in a dielectric matrix, multilayer NiFe-SiO2 nanocomposites were obtained. The entire sequence of technological processes using magnetron sputtering equipment in the presence of argon was presented, the aim of which was to create structures with different numbers and thicknesses of layers, as well as in two measurement configurations. Measurements of AC electrical properties were carried out in a variable temperature range, i.e. from room temperature to 373 K, using the 4-point method. The obtained measurement results were compared in terms of design parameters, such as thickness and number of layers, as well as technological parameters, such as heating duration. Structural analysis was performed using scanning electron microscopy (SEM) to investigate the effect of oxidation on the multilayer structures and to confirm the granular structure of the nanocomposite. Additionally, the chemical composition of the obtained multilayers was examined using Energy-dispersive X-ray spectroscopy (EDX). Resistive parameters were tested in the range of magnetic field induction from 0 T to 0.3 T. Based on the conductivity relationships, it was proven that a hopping mechanism of current conduction occurs in the tested samples. Using the frequency dependencies of the phase shift angle, it is possible to adjust the equivalent RC electronic circuit, thereby determining the potential application of the tested materials.

Enhancing the performance of PVC/PMMA polymer blend through hybrid nanofiller of TiO2 NPs/GNPs for capacitive energy storage applications

Polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) have been used as polymeric matrices for the synthesis of polymeric nanocomposite films that incorporate titanium oxide nanoparticles (TiO2 NPs) and graphite nanoplatelets (GNPs) as nanofillers. Based on TEM studies, TiO2 nanoparticles have a tetragonal anatase phase, ranging in size from 15 to 60 nm, whereas GNPs have a nanoplatelet-like shape, varying in thickness from 10 to 20 nm. XRD analysis shows that PVC/PMMA polymer nanocomposite samples have less crystallinity when added with TiO2 NPs and GNPs. Infrared Fourier analysis (FT-IR) indicated a complex interaction between the PVC/PMMA blend and both GNPs and TiO2 NPs. The UV/visible spectrum of the PVC/PMMA blend showed two absorbance peaks at 279 and 223 nm which may result from the n→π* and π→π* transitions. Moreover, optical bandgaps were reduced for both indirect and direct transitions when TiO2 NPs and GNPs were added. AC electrical conductivity and dielectric properties of the samples were measured at room temperature. Results indicated a significant increase in conductivity after filling from 2.6 x 10−14 S/cm for pure PVC/PMMA to 7.3 x 10−6 S/cm for PVC/PMMA-TiO2/GNPs nanocomposite. In addition, high nanoparticle concentrations lead to higher composite dielectric loss and dielectric constants. These findings suggest the possibility of using the prepared nanocomposites in capacitive energy storage and optoelectronic devices.

Preparation, structural, magnetic, and AC electrical properties of synthesized CoFe2O4 nanoparticles and its PVDF composites

This research focuses on the synthesis of nanoscale cobalt spinel ferrite (CoFe2O4) via the sol-gel auto-combustion method and its integration with polyvinylidene fluoride (PVDF) to fabricate CoFe2O4-PVDF nanocomposites. The characterization of cobalt ferrite, using techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), revealed a pristine cubic spinel structure with a mean crystallite size of 46.61 nm, and a homogeneous particle distribution. A key finding is a marked reduction in AC conductivity upon incorporating CoFe2O4 into the PVDF matrix, underscoring its potential in energy storage applications. The composite materials exhibit enhanced magnetic properties, including significant saturation magnetization and increased coercivity, making them prime candidates for high-density magnetic recording applications. Interestingly, the study also unveils that including CoFe2O4 in PVDF does not alter the beta phase of PVDF, highlighting the compatibility and stability of the composite formation. Furthermore, the impedance analysis of the ferrite and composite samples revealed the predominance of grain boundary resistance, offering more profound insights into their electrical behaviour. This finding is pivotal in understanding the electrical conduction mechanisms within these nanocomposites. Despite the comprehensive analysis, the absence of the highest peak in the loss tangent indicates the necessity for further investigation into the dielectric loss dynamics of these materials. Overall, this research significantly advances the understanding of CoFe2O4 nanostructures and their potential applications in advanced nanotechnology, particularly in energy storage and high-density magnetic recording. Future studies are expected to further refine these materials for a broader range of technological applications.

Effects of γ-Irradiation and Sample Aging on the AC-Electrical Properties of Epoxy/ZnO/CB Hybrid Nanocomposites

The goal of this paper is to study the effects of gamma irradiation and samples’ aging on the AC-electrical properties of hybrid epoxy resin as a function of frequency, temperature, and (zinc oxide) ZnO content (0, 0.049, 0.099, 0.149, and 0.199 wt) at 0.001 wt of conductive (carbon black) CB nanoparticles. The irradiation processes were administered at room temperature in a gamma chamber utilizing a Cobalt 60 source of average energy = 1.25 MeV with doses = 100, 750, and 1000 Gy. The AC-electrical properties, including the impedance, dielectric constant, dielectric loss, conductivity, and activation energy of the nanocomposites, were initially studied after years of sample preparations. The collected empirical data were later analyzed before and after the gamma irradiation. The results showed that exposing samples to different doses of gamma radiation affects these AC-electrical properties significantly. It was found that the energy gap decreased as the dosage of gamma radiation increased. This could be explained as the gamma-irradiation processes induce changes in the structure of the epoxy hybrid nanocomposites by reinforcing the metal–polymer bonding and hence, causing the release of more free electrons inside the hybrid nanocomposites. Moreover, the sample aging results showed that the AC-electrical conductivity decreased with time for all samples. Hence, this study demonstrated why the γ-irradiation technique can be considered a powerful way to treat, recover, and/or enhance the electrical features of the tested epoxy hybrid nanocomposites.

Electrical and dielectric characteristics of molybdenum dioxide nanoparticles for high-performance electrocatalysis

As an attempt to improve the catalytic processes in different electrochemical systems, molybdenum dioxide nanoparticles were prepared using the hydrothermal method, and their electrical and dielectric properties were investigated. The nanoparticles were polycrystalline with an orthorhombic structure. AC electrical transport properties of the pressed disc were conducted over a temperature range of 303–423 K and a frequency range of 42–5 × 106 Hz. The AC conductivity follows Jonscher's universal dynamic law, and it has been determined that correlated barrier hopping (CBH) is the primary conduction mechanism. The maximum barrier height (WM) was found to be 0.92 eV. The low activation energy showed that hopping conduction is the dominant mechanism of transporting current. The dielectric parameters were analyzed using both complex permittivity and complex electric modulus, with a focus on how they vary with temperature and frequency. At relatively high temperatures and low frequencies, the dielectric parameters showed a high-frequency dependence. The dielectric modulus showed that relaxation peaks move towards lower frequency when temperature increases. The dielectric relaxation activation energy, Δ Eω was determined to be 0.31 eV.

(Invited) Macroscopically Aligned Carbon Nanotubes for Photonics, Electronics, and Thermoelectrics

The remarkable flexibility, stable chemical structure, and extraordinary thermal, electrical, and optical properties of carbon nanotubes (CNTs) are promising for a variety of applications in flexible and/or high-temperature electronics, optoelectronics, and thermoelectrics, including wearables, refractory photonics, and waste heat harvesting. However, the long-standing goal in the preparation of CNT ensembles is how to maintain the extraordinary properties of individual CNTs on a macroscopic scale. The polydispersity and randomness remain two main challenges. Here, we will discuss different methods for creating macroscopically aligned CNTs, including spontaneous formation of wafer-scale aligned CNT films via controlled vacuum filtration and production of ultrahigh-conductivity CNT fibers and films through solution spinning and coating. We will then describe the optical, dc and ac electrical, thermal, and thermoelectric properties of these materials. These results are promising for device applications in various fields such as flexible CNT broadband detectors, spectrally selective thermal emitters, and thermoelectric devices.

IncorporatedTiO2nanoparticles intoPVC/PMMApolymer blend for enhancing the optical and electrical/dielectric properties: Hybrid nanocomposite films for flexible optoelectronic devices

AbstractIn the present work, sol–gel‐synthesized titanium oxide nanoparticles (TiO2NPs) were added to polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) to create polymer nanocomposites (PNCs) samples. The preparation was carried out via the solution casting method. The synthesized TiO2NPs have a tetragonal anatase phase and an average grain size of 15.7 nm. XRD analysis reveals that the TiO2NPs' addition to PVC/PMMA causes a decrease in the crystallinity of PNCs films. Infrared Fourier analysis demonstrated the interplay/complexity between the PVC/PMMA blend and TiO2NPs. The UV/visible spectrum of the PVC/PMMA blend showed two absorbance peaks at 278 and 208 nm, which may result from the n → π* and π → π* transitions. Also, optical bandgaps for indirect and direct allowed transitions decreased with increasing TiO2NPs concentration. The samples' AC electrical conductivity and dielectric properties were measured at room temperature. As the TiO2NPs content in the nanocomposite rises, a percolating network begins to emerge inside the composite, demonstrating that AC electrical conductivity obeys Jonscher's law. Additionally, it has been demonstrated that nanoparticle concentration leads to a higher composite dielectric loss and dielectric constant. These findings suggest the possibility of using the prepared nanocomposites in capacitive energy storage and optoelectronic devices.HighlightsPVC/PMMA‐TiO2nanocomposites' films were fabricated via the solution casting method.Adding TiO2NPs to PVC/PMMA reduces the crystallinity of the PNCs films.The allowed direct and indirect bandgaps decreased with rising TiO2NPs content.AC conductivity, impedance, and dielectric characteristics were discussed.The findings indicate the use of prepared samples in optoelectronic devices.

Organic Solar Cells: An Analysis of AC and DC Electrical Properties

In this paper, AC and DC electrical properties of organic solar cells based on P3HT:PCBM active layer have been investigated. The performance of such solar cell has demonstrated the efficiency of 2.31% corresponding with short-circuit current density of 6.08 mA ⋅ cm[Formula: see text], open circuit voltage of 0.64 V and fill factor of 60%. The equivalent circuit and the properties of the supposed interfaces between the layers in the P3HT:PCBM-based solar cell have been estimated. AC properties have demonstrated series capacitance increasing with increasing frequencies, which means series capacitance saves charges and parallel capacitance has decreased with increasing of frequency work as discharge part of charges stored in series capacitance. Also, equivalent series and parallel resistances have demonstrated a decrease from 7 [Formula: see text] and 120 k[Formula: see text] at low frequency to 1 [Formula: see text] and 43 k[Formula: see text] at high frequencies, respectively.

Effects of Gamma Radiation Doses on the AC Electrical Properties of Epoxy Reinforced with Nano-Silica Composites

This study reports the effects of gamma radiation on the AC electrical properties of epoxy nano-silica composite sheets with an average thickness of 3 mm. Epoxy reinforced with different nano-silica concentrations of 0, 5, 10, and 15 wt.%. The epoxy nano-silica composites were exposed to different gamma radiation dosages of 1, 3, and 5 kGy. The data were analyzed before and after gamma irradiation and the results showed that the AC electrical properties of the gamma-irradiated epoxy nano-silica composites varied from those of the non-irradiated samples. We found that there were significant changes in the impedance, dielectric constant, dielectric loss, and AC electrical conductivity values of the epoxy nano-silica composites after irradiation, and the AC electrical conductivity and dielectric constant values of the nano-silica composites were enhanced by exposing the samples to gamma radiation because more free electrons were released inside the epoxy nano-silica composites. The AC electrical properties, such as impedance, dielectric constant, dielectric loss, and electrical conductivity, of the epoxy nano-silica composites were studied and discussed before and after gamma radiation with different dosages. We found that these AC electrical properties marginally increased with increasing doses of gamma irradiation.

Improvement structural and dielectric properties of PS/SiC/Sb2O3 nanostructures for nanoelectronics devices

In the current study, the PS/SiC/Sb2O3 nanocomposites have been prepared by using solution casting method with different concentrations of SiC/Sb2O3 nanoparticles (0,2,4,6,8) % wt. The structural and dielectric properties of (PS/SiC/Sb2O3) nanocomposites have been investigated. Full emission scanning electron microscope (FE-SEM) used to study the surface of nanocomposite. FE-SEM confirmed that good distribution of SiC and Sb2O3 NPs into the polymer matrix. Optical microscope (OM) was tested the morphological of nanocomposite that proven that the polystyrene is exceptionally miscible, as seen by its finer form and smooth, homogeneous surface, while the additive concentration SiC and Sb2O3 NPs are well distributed on the surface of the polymer nanocomposite films. Fourier transformation spectroscopy (FTIR) was examine the structural of nanocomposite and give the information of the vibration of molecules. From FTIR, the additive SiC and Sb2O3 NPs caused interaction with polymer matrix. FTIR proven that there is physical interactions between polystyrene and SiC and Sb2O3 NPs. According to AC electrical properties, dielectric constant and dielectric loss of the NCs reduce with increasing the frequency of the applied electric field and increased with increasing concentration of SiC/Sb2O3 nanoparticles, while AC electrical conductivity increased with increasing frequency and concentration of SiC/Sb2O3 NPs. The results of structural and electrical characteristics show that the PS/SiC/Sb2O3 nanocomposites may be used for various electronics devices.

Effect of Si3N4/TaC nanomaterials on the structural and electrical characteristics of poly methyl methacrylate for electrical and electronics applications

In this study, the casting method was used to prepared PMMA/Si3N4/TaC nanocomposites with variant content (0,2,4,6,8) % wt of Si3N4/TaC nanoparticles. The structural and electrical properties have been investigated. Scanning electron microscope (SEM) indicate that the homogenous, smooth and dispersed of Si3N4 and TaC NPs inside the PMMA matrix due to strong covalent interaction between the Si3N4 and TaC NPs in the PMMA matrix which mean a good method for prepared films. Optical microscope images explained that when increasing in content of nanoparticles that forming network paths inside the polymeric matrix that act as charge carriers. FTIR spectra indicate to a physical interference between the polymer matrix and nanoparticles. The AC electrical properties of nanocomposites obtained that the dielectric constant and dielectric loss rise with rising content of nanoparticles and decrease with rising frequency of applied electric field. While the A.C electrical conductivity rise with rising the frequency and weight content of Si3N4/TaC nanoparticles. This results indicated that the PMMA/Si3N4/TaC nanostructures can be considered as promising materials for electronics and electrical nanodevices.

Effect of carbons' structure and type on AC electrical properties of polymer composites: predicting the percolation threshold of permittivity through different models.

The online version contains supplementary material available at 10.1007/s00396-023-05120-2.

Growth of New, Optically Active, Semi-Organic Single Crystals Glycine-Copper Sulphate Doped by Silver Nanoparticles

The purpose of this study is to modify all physicochemical properties of glycine–copper sulphate single crystals, such as crystal habits, molar mass, thermal stability, optical activity, and electrical properties. The novelty of this study is growth of glycine–copper sulphate single crystals doped by a low concentration of silver nanoparticles (SNPs) that improved both crystal habits and physicochemical properties. The originality of this work is that trace amounts of SNPs largely increased the crystal size. Crystals have molar stoichiometric formula [glycine]0.95, [CuSO4·5H2O]0.05 in the absence and presence of silver nanoparticles (SNPs) in different concentrations: 10 ppm, 20 ppm, and 30 ppm. The crystals’ names and abbreviations are: glycine–copper sulphate (GCS), glycine–copper sulphate doped by 10 ppm SNPs (GCSN1), glycine–copper sulphate doped by 20 ppm SNPs (GCSN2), and glycine–copper sulphate doped by 30 ppm SNPs (GCSN3). Dopant silver nanoparticles increased: crystallinity reflecting purity, transparency to UV-Vis. electromagnetic radiation, thermal stability, and melting point of glycine–copper sulphate single crystal. GCSN3 is a super conductor. High thermal conductivity of crystals ranging from 1.1 W·min−1·K−1 to 1.6 W·min−1·K−1 enabled attenuation of electromagnetic radiation and rapid heat dissipation due to good dielectric and polar properties. On rising temperature, AC electrical conductivity and dielectric properties of perfect crystal GCSN3 increased confirmed attenuation of thermal infrared radiation.

Impact of Antioxidants on DC and AC Electrical Properties of XLPE-Based Insulation Systems

Impact of Antioxidants on DC and AC Electrical Properties of XLPE-Based Insulation Systems

AC electrical properties of CNF/PTFE composite

In conductive nanocarbon-based polymer composite systems, carbon-nano-fibers (CNFs) provide good connectivity for electrical conduction due to their micrometer (μm) length compared to nano-meter (nm) length of carbon-nano-tubes (CNTs). However, an excellent electrical conductivity is demonstrated by the CNT compared to a CNF. This paper reports the AC electrical properties of CNF/PTFE composites prepared with partially coated CNF with PTFE. The sample structures were studied by means of Scanning Electron Microscopy (SEM). A negative capacitance (NC) has been observed in CNF/PTFE composites. The positive value of the imaginary part of impedance indicates the inductive nature of composites within applied frequencies (upto 1 MHz).