Ac Conductivity Research Articles

Unveiling the role of ZrO2 doping in Sr2SmTi2Nb3O15 ceramics: From structural study to dielectric enhancement

Solid-state processing was used to synthesize tungsten bronze type (TTB) solid solutions, specifically Sr2Sm(Ti1-xZrx)2Nb3O15 with x values of 0, 0.2, 0.3, and 0.4. The study examined the crystalline structure, optical properties, morphology, and electrical and dielectric characteristics of these compounds. X-ray diffraction revealed a tetragonal structure (space group P4bm). Scanning electron microscopy showed significant sample densification with grain sizes decreasing from 6.19 μm to 2.78 μm. Dielectric measurements indicated that the dielectric constant varied from 150 for x = 0 to 567.24 for x = 0.2, then decreased to 380.88 for x = 0.4, with the x = 0.3 compound having the lowest dielectric loss. The Curie temperature (Tc) decreased from 332 °C to 248.5 °C with increasing Zr content, corresponding with a reduction in grain size. The energy gap (Eg) narrowed from 2.914 eV to 2.714 eV as Zr content increased. AC conductivity increased with temperature and frequency. Electrical conductivity followed Jonscher's power law, with activation energies decreasing from 1.54 eV to 0.87 eV, explained by the small polaron tunneling (NSPT) model.

Crystal Structure and Spectroscopic Characterization of a New Hybrid Compound, (C12H17N2)2[CdBr4], for Energy Storage Applications.

Organic-inorganic hybrid materials have recently found a vast variety of applications in the fields of energy storage and microelectronics due to their outstanding electric and dielectric characteristics, including high dielectric constant, low conductivity, and low dielectric loss. However, despite the promising properties of these materials, there remains a need to explore novel compounds with improved performance for practical applications. In this research paper, the focus is on addressing this scientific challenge by synthesizing and characterizing the new-centrosymmetric (C12H17N2)2[CdBr4] crystal. This compound offers potential advancements in energy storage technologies and microelectronics due to its unique structural and electronic properties. The chemical mentioned above crystallizes in the monoclinic system, and its protonated amine (C12H17N2)+ and isolated anion [CdBr4]2- are bound by C-H···π and N-H···Br hydrogen bonds to form its zero-dimensional structure. Through optical absorption analysis, the semiconductor nature of the material is verified, showcasing a band gap of around 2.9 eV. Furthermore, an in-depth examination of Nyquist plots reveals the material's electrical characteristics' sensitivity to frequency and temperature variations. By applying Jonscher's power law to analyze ac conductivity plots, it is observed that the variation in the exponent "s" accurately characterizes the conduction mechanism, aligning with CBH models. The compound exhibits low dielectric loss values and a high permittivity value (ε ∼ 105), making it a promising candidate for energy storage applications. By managing the scientific challenge of improving material performance for energy storage and microelectronics, this research contributes to advancing the field and opens avenues for further exploration and application of organic-inorganic hybrid materials.

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

Influence of Zr4+-Co2+ substitution on structure, morphology and dielectric properties of BaZn2U-type hexaferrites

A series of Zr4+-Co2+ substituted U-type hexaferrites (Ba4Zn2Fe36-2xZrxCoxO60 (0.0 ≤ x ≤ 1.0, having Δx = 0.25)) were synthesized via sol-gel auto-combustion method. The samples were sintered at 1200 ° C for 6 h. The impact of Zr–Co substitution on phase, structure, morphology, and dielectric behavior were investigated through XRD, FTIR, SEM, XPS and VNA. XRD studies shows that the U-type hexaferrite phase has been developed and the increase in lattice constants (a & c), cell volume, c/a ratio, and percentage porosity was observed. Sample with x = 0.25 exhibited the smallest crystallite size (34.5 nm). The existence of signature metal-oxygen vibrational bands for hexaferrites was observed by FTIR spectra. SEM analysis reflects that the substitution produces a significant effect on morphology and grain size of the samples. X-ray photoelectron spectra (XPS) of sample x = 1.0 confirmed the chemical and elemental composition. The dielectric constant, dielectric loss, and ac conductivity increases with increasing frequency and decreases with Zr–Co substitution. The lowest reflection loss of RL = −64.5 dB (with MW absorption >99.9 %) was observed for the composition x = 0.5 with pellet thickness of 1.73 mm at 1.05 GHz frequency. Due to the improved bandwidth and better absorption, these hexaferrites can be used in microwave and high frequency applications.

Investigating grain and grain boundary effects on charge transport and dielectrics in BaCoxAlxFe12-2xO19 nanoferrites

This investigation centres on the sol-gel preparation of M-type barium hexagonal ferrite (M-BaFe12O19) incorporating Co2+ and Al3+ as dopants. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were employed to assess the impact of dopants on the crystallographic structure and microstructure. The dielectric characteristics, electric modulus, impedance, and conductivity of the synthesized materials were evaluated at ambient temperature using an impedance analyzer. The structural analysis verified the presence of the hexagonal M-type crystal phase. Increasing dopant levels led to a reduction in lattice parameters, signifying unit cell shrinkage. FESEM imaging exposed the emergence of needle-shaped grains resulting from the doping process. Dielectric spectroscopy showed a decrease in both the dielectric constant (from 135.95 at x = 0.0 to 39.8) and the loss tangent (from 3.68 to 0.610) as dopant concentration increased. Conductivity exhibited relaxation at varying intervals, supported by the electric modulus spectra, which validated non-Debye relaxation behavior. Both relaxation time and AC conductivity diminished with higher dopant concentrations (from 0.000222 Ωm−1 to 0.000036 Ωm−1). The relaxation observed in conductivity and dielectric responses implies their contribution to the charge transport processes within BaCoxAlxFe12-2xO19. Electrochemical impedance spectroscopy (EIS) software was used to generate complex impedance plots, which aligned with the experimentally obtained impedance values for the synthesized compositions. Micrographs revealed a distribution of grains and grain boundaries that were consistent with calculated characteristics. This further substantiates the measured dielectric and electrical parameters.

Polaron-mediated transport and relaxation phenomena in the lead zinc niobate (PZN) modified bismuth ferrite solid solution

To investigate the dielectric and conductivity properties of PZN modified BF solid solution high temperature mixed oxide technique is employed. The material is subjected to analysis using XRD, SEM, and impedance spectroscopy. A polycrystalline PZN-BF sample with an average crystallite size of 63.3 nm has been formed. The scanning electron micrographs show that the grains and grain boundaries are distributed suitably. dielectric characteristics of the 0.1PZN-0.9BF compound are studied at frequencies ranging from 1 kHz to 1 MHz and temperatures ranging from ambient temperature to 400 °C. The confined mobility of charge carriers causes nearly continuous loss (NCL) behavior at low temperatures (<200 °C). High-temperature relaxation resulting from charge carrier hopping induces maximum loss and elevated conductivity. Rendering to the Overlapping Large Polaron Tunnelling (OLPT) model of conductivity, the transport mechanism in this modified BiFeO3 (BF) compound is facilitated by the short-range hopping of polarons. The NTCR behavior from Arrhenius plot of ac conductivity and temperature independent conductivity relaxation from loss modulus (M'') analysis are demonstrated. Sensors, actuators, and optoelectronic devices can benefit from the PZN-modified BF compound's electrical and dielectric characteristics, which have been studied in detail.

Evaluation of thermal conductivity models and dielectric properties in metal oxide-filled poly(butylene succinate-co-adipate) composites

This study examines how various nanofillers impact thermal conductivity, dielectric characteristics, and electromagnetic interference (EMI) shielding potential of bio-based and biodegradable poly(butylene succinate-co-adipate) (PBSA). TiO2, NiFe2O4, Fe2O3, and Fe3O4 were selected as fillers for nanocomposites at 4–50 vol.% (12–81 wt.%). The nanocomposites were analyzed in three domains: structural (scanning electron microscopy, energy dispersive X-ray spectroscopy mapping, density, tensile testing), thermal (light flash analysis, literature models), and dielectric (AC conductivity, permittivity, EM shielding effectiveness (SE)). The investigated fillers showed good dispersion and compatibility with the PBSA matrix. LFA was analyzed according to literature models, where Bruggeman and Agari models showed the best fit at high concentrations. The dielectric analysis revealed that most of the nanocomposites did not reach percolation; thus, producing thermally conductive plastics that are electrically insulating. EMI shielding was limited to frequencies below 10 Hz, with the notable exception of Fe3O4 (100 nm and loading of > 25 vol.%), which showed shielding at frequencies up to 105 Hz. The investigated composites based on a biodegradable polyester and abundant metal oxide nanofillers are suitable for the production of cheap, ecological, and electrically insulating heat dissipation solutions required for modern and lightweight applications.

Effect of tin doping on the structural, optical, and dielectric properties of unintentionally β-Ga2O3 single crystal

This paper studied the structural, optical, electrical, and dielectric properties of the undoped and 0.05 mol% Sn-doped β-Ga2O3 single crystals through comprehensive characterizations by x-ray diffraction (XRD), Raman scattering, Optical transmittance spectroscopy, x-ray photoelectron spectroscopy (XPS), Ultraviolet photoelectron (UPS) spectroscopy, and dielectric measurements. The optical bandgap decreases as Sn content increases. The results of XPS showed that Sn atoms were successfully added to the host β-Ga2O3 crystal. The position of the Fermi level of 0.05 mol% Sn-doped β-Ga2O3 is calculated to be 2.56 eV above the valence band and 1.85 eV beneath the conduction band. Also, the computed value of the work function of 0.05% mole Sn-doped β-Ga2O3 is 4.53 eV. AC conductivity increases, while dielectric loss and dielectric constant decrease with increasing frequency.

Influence of barium titanate and graphite on electrical attributes of Polyvinylidene fluoride matrix composites

Binary and ternary composite nanofibers were synthesized by adding different weight ratios of Barium titanate (BT) and Graphite (G) in Polyvinylidene fluoride (PVDF) via electrospinning technique. The electrical properties of these composite materials were measured using an LCR meter. Fourier-transform infrared spectroscopy (FTIR) was used to analyze functional groups, while scanning electron microscopy (SEM) was used to investigate surface morphology. The FTIR analysis indicated discernible interactions between PVDF, BT and G at different weight percentages, while SEM micrographs showcased the formation of nanofibers. The incorporation of 5 wt% BT in PVDF led to a 45 % increase in dielectric constant, a 40.5 % increase in capacitance, a 1.88 % rise in dielectric loss and a 42.6 % increase in AC conductivity. Interestingly, the addition of small amount, i.e., 0.5 wt%, of graphite to PVDF +5 wt% BT resulted in a further rise of 9.5 % in dielectric constant, a further increase of 50.4 % in capacitance, and a reduction of 8.58 % in dielectric loss and 4 % in AC conductivity at the highest frequency of 2 MHz. These composites showed potential for use as dielectric materials in high-frequency microelectronic devices.

A novel conductive nano-based flame-retardant coating: Preparation and its application for cotton fabric

A novel coating consisting of polyvinyl alcohol (PVA), folic acid (FA), and polyaniline nanoparticles (PANI) was applied to cotton fabric (CF) to enhance its flame retardancy, thermal stability, and electrical properties. The results from different flammability tests indicated a synergistic effect between FA and PANI to enhance the flame retardancy of CF at low weight gain percentages. The rate of burning data displayed that the new coating stopped the flame propagation in CF. The limiting oxygen index (LOI) of CF increased from 18 % to 26.9 % in the sample coated with PVA/FA/PANI. The new coating improved the thermal stability and char residue formation of CF at high temperatures. Moreover, it succeeded in decreasing the smoke density, and the production of toxic gases during treated CF combustion. The tensile strength and colour strength of CF were improved after the addition of PVA/FA/PANI coating. The surface resistance and the AC conductivity of the coated CF were measured. The addition of PVA/FA/PANI to CF increased the AC electrical conductivity due to the growth of conductive paths between the CF and the new coating material.

Simulations of optical and dielectric properties of plasmonic Ag–LiNbO[formula omitted] metamaterial: Analysis of the geometrical parameters

We report the optical absorption of a multilayer system and the electrical properties of silver (Ag) naoparticles (NPs) embedded on LiNbO3 that acts as active layer. The multilayer system is constituted by Indium Tin Oxide (ITO), a square lattice of Ag NPs on the uniaxial crystal LiNbO3, the polymer PMMA and a substrate of SiO2. The effective dielectric function of the ensemble aggregates of Ag NPs and uniaxial LiNbO3 crystal are treated through the extended Maxwell–Garnett approximation. The multilayer absorbance for s- and p-polarization at normal and oblique incidences is determined by means of the Transfer Matrix Method. We demonstrate that an adequate choice of structural parameters such as NPs sizes, interparticle distances and layers thicknesses can produce an enhancement of optical absorption in the multilayer system. For filling factor higher, the system absorbance is greater. The Brewster angle is seen to be sensitive to the Ag NPs size, as far as the wavelength is varied. In addition, we evaluate the dielectric modulus parameter and the ac–electrical conductivity of the effective medium layer (active layer) in the perpendicular and parallel directions of the Ag NPs plane. For both directions, at f sufficiently high, we find the negative epsilon condition, typical characteristic observed in metamaterials. For the ac–electrical conductivity, we identify different resonances for the perpendicular and parallel directions. A bigger concentration of Ag NPs induces a higher intensity of ac–conductivity.

Effect of Sodium Ion Addition on Copper Selenide/Chitosan Film Towards Electrical and Shielding Efficiency Improvement

The operation of electronic devices can be disrupted by unwanted electromagnetic signals, affecting its operation. Deploying electromagnetic shielding is a viable solution to minimize the impact of electromagnetic interference (EMI). The conventional methods of electromagnetic shielding use metal gaskets to safeguard sensitive electronic components, which have drawbacks of cost and weight. Hence, electromagnetic shielding polymer can be an alternative to replace metal gaskets. This work investigates the effect of sodium ion (Na) addition to copper selenide/chitosan (CuSe/Ch) film for electromagnetic shielding applications. The shielding polymers were produced using solution casting methods, while the CuSe was synthesized using the chemical coprecipitation method. Impedance spectroscopy and two port waveguide methods were used to characterize the prepared polymer's electrical properties and shielding efficiency. The results indicate that Na incorporation in the CuSe/Ch film resulted in a 47 % decrease in bulk resistivity and increased DC conductivity from 6.07 × 10-6 S/cm to 3.69 × 10˗5 S/cm. The AC conductivity of films containing Na demonstrates a similar level of conductivity at lower frequencies, followed by a sharp increase at higher frequencies, indicating a more substantial influence of Na at higher frequencies. Higher absorption shielding efficiency (SEA) and lower reflection shielding efficiency (SER) were achieved by introducing Na into the CuSe chitosan film. The Na/CuSe/Ch film shows higher total shielding efficiency at an average of 20 dB, equivalent to 99 % of the EM power shield.

Investigations on structural and electrical properties of YMnO3 based mixed valent manganites

In this communication, the effect of doping of divalent cations (Sr, Ca) at Y–site in pure YMnO3 on their structural and electrical properties has been investigated. X–ray diffraction reveals dual phase nature of Ca–doped sample. The dielectric behaviours have been fitted using cole–cole relaxation. Role of secondary phase of 41% hexagonal YMnO3 coexists with 59% orthorhombic Y0.9Ca0.1MnO3 for Ca–doped YMnO3 compound has been discussed where orthorhombic phase provides major contribution for large dielectric constant. The ac conductivity has been explained by correlated barrier hopping mechanism. The current–voltage characteristics have been understood using Simmon’s model.

Impact on activation energy with elevating calcination temperature of barium bismuth ferrite nanocomposite

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

The electrical transport property and gas detection behaviour of polyvinyl alcohol and γ-Fe2O3 nanocomposite film

This paper presents the electrical and gas detection behaviour of polyvinyl alcohol (PVA)/γ-Fe2O3 nanocomposite films. The physical characterization includes X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and UV–Visible spectroscopy. The analysis of both the dc resistivity and ac conductivity using Correlated Barrier Hoping (CBH) conduction process shows that the conductivity enhances with the decreasing of activation energy in case of the PVA/γ-Fe2O3 nanocomposite film which is the indication of interfacial defect states. The current voltage study at various temperatures follows the thermoionic emission model of Schottky Barrier diode. Moreover, the dielectric constant enhances for PVA/γ-Fe2O3 nanocomposite film, which indicates homogeneous distribution of γ-Fe2O3 nanoparticles within PVA matrix and the aggregation of trapped charges found in interface develops an interfacial polarization. As a result, the gas adsorption capacity of the nanocomposite film increases which improves the signal-to-noise ratio, leading to higher gas detection sensitivity.

A double-layer light shutter consisting of polymer dispersed liquid crystal and azo dye/quantum dot

We have developed a double-layer liquid crystal light shutter and investigated its temperature dependent morphological, electro-optical, and dielectric properties. The optical layers of the shutter are in direct contact, reducing optical losses. The shutter comprises a polymer dispersed liquid crystal film adjacent to an azo dye methyl red and CdSeS/ZnS quantum dot doped cholesteric liquid crystal layer. This novel double-layer light shutter device is switchable between opaque and transparent states at room temperature, and it exhibits low threshold and saturation voltages. Both the threshold (Vth) and saturation (Vsat) voltages are found to decrease with increasing temperature. The electrical characteristics of the shutter, namely the real part of dielectric constant (ε′) and the ac conductivity (σac) also increase with temperature in the low frequency region. Our results show that this double-layer light shutter has interesting potential for simple electro-optical devices and smart window applications.

Synthesis of ZnO and CuO–ZnO nanocomposites for photo-conducting and dielectric applications

Zinc oxide (ZnO) and its composites has garnered a tremendous attention lately due to its effective role in electronic and optoelectronic applications. The present manuscript reports the synthesis and characterization of ZnO and CuO–ZnO nanocomposites. These samples were synthesized using precipitation technique and studied for voltage-dependent dielectrics and photoconductivity properties. Structural properties were thoroughly investigated using powder X-ray diffraction (PXRD) measurements. The composite material revealed decreased crystallinity and increased strain in the material. Optical absorption measurements were recorded using UV–vis diffusion reflectance measurements and the changes in the absorbance spectrum corresponding bandgap is explored. The obtained band gap is comparatively less for the composite material when compared with prestine ZnO. Structural morphology of the synthesized materials was observed and compared and changes in the composites when compared with the ZnO. Drastic changes in the morphology is witnessed. Electrical response of these synthesized semiconductors was studied using I–V and dielectric measurements. CuO–ZnO samples show a very clear sensitivity to the voltage dependent dielectric properties compared to ZnO. The composite and ZnO are studied using I–V measurements and the light dependent I–V measurements and composite revealed photo sensitivity. Drastic change in the conductivity is witnessed inferring the material to be used in optoelectronic application. Dielectric, Impedance, dielectric loss, AC conductivity and modulus index of the materials were explored by subjecting the materials to impedance measurements. The materials were also explored with different voltages and compared. The composite material revealed drastic variations for change in the voltage and measured parameters were compared with the ZnO.

Comprehensive structural, optical, electrical, dielectric and magnetic analysis of co-precipitated Mg-Zn-Cu-Ce soft ferrites

The Mg0.6Zn0.2Cu0.2Fe2-xCexO4 series (0.0, 0.0125, 0.0250 and 0.0375) was prepared by coprecipitation and characterized by X-ray diffraction (XRD), UV–vis, Fourier transform infrared spectroscopy (FTIR), current and voltage (I-V), an LCR meter and a vibrating sample magnetometer (VSM). XRD analysis revealed a cubical structure with crystallite sizes ranging from 37.42 to 19.20 nm and lattice constants varying between 8.3938 and 8.4301 Å. Absorption bands, i.e., octahedral bands (533.87 – 533.99 cm−1) and tetrahedral bands (420.73 – 415.96 cm−1), were detected to confirm the occurrence of metal oxides. The ranges of the optical band gap energy (Eg = 2.782 – 2.756 eV) and DC resistivity (ρDC = 5.309 × 109 Ohm.cm to 2.071 × 1010 Ohm.cm) revealed the semiconducting nature of the composed ferrites. The dielectric constant and loss, AC conductivity and impedance were determined, and sample Mg0.6Zn0.2Cu0.2Fe0.0125Ce1.9875O4 exhibited the highest dielectric constant. The saturation magnetization (Ms = 12.7625 – 21.9460 emu/g) and remanence (Mr = 8.5460 – 15.6781 emu/g) increased, while the coercivity (Hc = 796.76 – 660.91 Oe) decreased. The determined values of the microwave frequency “ωm” indicate that ferrites are applicable in wireless communication systems.

Synergistic effects of Li-based ferrite and graphene oxide in microwave absorption applications

The successful fabrication of composites consisting of ferrites with a composition of Li0.4Mg0.25Zn0.25Fe2.2O4 and Graphene oxide was carried out using the ultra-sonication technique. The current study examined the impact of graphene oxide in spinel ferrite employing X-ray diffraction, dielectric, and magnetic susceptibility studies. The X-ray diffraction investigation confirmed the spinel phase formation in ferrite and graphene oxide synthesis. The measured range for the size of crystallites was found to be between 48.43 and 30.07 nm. The DC resistivity of cubic ferrite at room temperature was determined to be 1.715 ×1010 ohm-cm by a two-probe approach. Furthermore, it was observed that the resistivity fell significantly as the content of graphene oxide increased. The dielectric constant exhibited behavior consistency with the Maxwell-Wagner phenomenon of interfacial polarization. The rise in graphene oxide content in ferrite results in high AC conductivity of composites due to the relatively large value of conductivity of graphene oxide and the improved charge hopping mechanism. The magnetic susceptibility of all the samples demonstrated a progressive decline as the temperature increased, which can be attributed to the disruption of spin alignment at the Curie temperature. The observed Curie temperature of all samples was 413–473 K. Integrating spinel ferrite with Graphene oxide has significantly improved the magneto-electrical characteristics, indicating potential applications in supercapacitors, high-frequency electromagnetic devices, and microwave absorption.

DC current–voltage and impedance spectroscopy characterization of nCdS/pZnTe HJ

This paper describes the electrical and dielectric behavior of the nCdS/pZnTe HJ by current–voltage, capacitance–voltage characteristics, and impedance spectroscopy in a temperature interval 220–350 K. A microcrystalline p-ZnTe layer and n-CdS were grown on glass/ZnO substrate by closed space sublimation method. As frontal contact to CdS, the transparent ZnO and as a back contact to ZnTe, silver conductive paste (Ag) treated at 50 °C in vacuum were used. The current–voltage results of nCdS/pZnTe HJ show a rectifying behavior. The junction ideality factor, barrier height, and series resistance values were extracted from the rectifying curves at different temperatures. The built-in voltage, carrier concentration and depletion width were obtained from the capacitance–voltage measurements. Analysis of the J–V–T and C–V–T characteristics shows that the thermionic emission and recombination current flow mechanisms dominate in the nCdS/pZnTe HJ. The dielectric study reveals that the experimental values of the AC conductivity, dielectric constant, dielectric loss, the imaginary part of the electric modulus are found to be very sensitive to frequency and temperature. The dielectric constant and dielectric loss are observed to be high at the low frequency region. The increase in the values of electric modulus with the frequency implies an increase in the interfacial polarization at the interface of nCdS/pZnTe HJ. Jonscher’s universal power law shows that with increasing frequency, AC conductivity increased. The results conductivity show that the ionic conductivity and interfacial polarization are the main parameters affecting the dielectric properties of the device when the temperature changes.