Ac Conductivity Research Articles

AC Impedance Analysis of Blend Polymer Electrolyte of PVP – PPA with Magnesium Salts as an Ionic Dopant for Potential Battery Applications

Abstract Solid polymer electrolyte films containing blend polymer electrolyte of Polyvinylpyrrolidone (PVP) and Poly p - amino benzoic acid (PPA) with varying ratios of magnesium salts were synthesized by solution casting method. Their conduction and relaxation mechanisms were studied by impedance spectroscopy (AC) at room temperature. The dependence of electrical data on frequency was analyzed by Cole – Cole plot and Jonscher’s power law. The semicircle seen in the plot represents the double relaxation process and shows how bulk electrolyte and the interfacial effect contribute to non-Debye and electrical conduction. The ac and dc conductivity values were calculated and the conductivity variation for the blend polymer PVP – PPA doped with different concentrations of magnesium salts was explained by the ionic contribution of the electrolytes. The dielectric constant and dielectric loss were measured by the dielectric investigations. The relaxation phenomenon of these electrolytes is provided by the dissipation factor analysis and electric modulus value. The conductivity of the system determines the suitability of the thin film concentration for potential battery applications as a polymer electrolyte.

Ionic liquid based NCPBE membranes for electrochemical capacitor applications: Structural, thermal and electrical transport properties

The current study focuses on the preparation and characterisation of imidazolium ionic liquid based plasticized nano-composite polymer blend electrolytes (NCPBEs). Semi-crystalline nature of the synthesized samples was observed using XRD analysis. ATR-FTIR results demonstrate the interaction among the carbonyl (CO) and hydroxyl (O–H) groups of polymers with ionic liquid (IL) and salt, NaI. Furthermore, thermo-gravimetric analysis (TGA) indicates multi-step decomposition process. Ion transport mechanism has been analysed using temperature dependent conductivity analysis, ac conductivity analysis and dielectric properties study. The sample containing 25 wt% IL i.e. NCPBE-25 has the ionic conductivity ∼9.30 × 10−4 Scm−1 with the optimum vale of charge carrier density, mobility, and ion diffusivity at 30oC. Ions are principal charge carriers in the present electrolytes. The sample NCPBE-25 has the electro-chemical stability window −3.6 to 1.5 V at room temperature. The fabricated electro-chemical capacitor has the specific capacitance, energy density and power density 363.27 Fg-1, 50.45 Whkg−1 and 18.16 kW/kg, respectively at the scan rate 5 mV/s.

Investigation of Zn Doped Li1.5Al0.5−xZnxGe1.5(PO4)3 (x = 0, 0.1 & 0.2) as a Solid Electrolyte for Li Ion Batteries

All solid lithium-ion batteries (ASLB) have gained a lot of attention as it could deliver high energy and power density. In order to completely establish ASLB, proper understanding of solid electrolyte is very vital and the research from diverse point is still undergoing. Among them, NASICON-type phosphate based solid electrolytes are one of the promising materials due to good ionic conductivity and atmospheric stability. Addition of proper dopants into the parent material could cause an increment in their ionic conductivity as well as stability, thus fitting the material apt as solid electrolyte. This study aims in understanding the effect of ionic conductivity and stability of Lithium Aluminium Germanium Phosphate (LAGP) material upon adding Zinc as dopant material. We explored the effect of structural, ionic conductivity, stability against Li and Ac conductivity properties of Li1.5Al0.5−xZnxGe1.5(PO4)3 solid electrolyte with x = 0, 0.1 and 0.2. Our study showed that doping of aluminium with slightly bigger Zn ion could enhance the stability and conductivity of the material without changing the crystal structure. When x = 0.1 the ionic conductivity of the material attained is 1 × 10−5 S cm−1 at RT, which reaches 2.57 × 10−5 S cm−1 at 60 °C. Such a change in conductivity arises due to the expansion of ionic pathways which can be further tuned by exploring the limiting concentration 0 ≤ x < 0.1. Moreover, the sample also showed good stability at 0.03 and 0.05 mA cm−2 current densities against Li metal. Present study shows that Zn doping can improve the ionic conductivity of LAGP moderately and it can be used as a solid electrolyte for fabricating all-solid-state batteries.

Electrical transport and dielectric relaxation mechanism in Zn0.5Cd0.5Fe2O4 spinel ferrite: A temperature- and frequency-dependent complex impedance study

In the present study, the frequency-dependent dielectric relaxation and electrical conduction mechanisms in sol-gel-derived Zn0.5Cd0.5Fe2O4 (ZCFO) spinel ferrite were studied in the temperature range of 343–438 K. The formation of the ZCFO spinel ferrite phase with space group Fd3m was confirmed by X-ray diffraction analysis. The dielectric relaxation and electrical conduction mechanisms were studied using complex impedance spectroscopy (CIS). In the Nyquist plots, depressed semicircles were fitted with an equivalent circuit model with configuration (RGBQGB) (RGQG), signifying the contributions from grain boundaries and grains to the charge transport mechanism in the sample. The frequency-dependent AC conductivity was found to follow Jonscher's power law, and the frequency exponent term depicted the overlapping large polaron hopping (OLPH) model as the dominant transport mechanism. The activation energies for conductivity, electric modulus and impedance were calculated to identify the nature of the charge carriers governing the relaxation and conduction mechanisms in the prepared sample. Complex modulus studies confirmed the non-Debye type of dielectric relaxation, whereas tangent loss and dielectric constant analyses confirmed the thermally activated hopping mechanism of charge carriers in Zn0.5Cd0.5Fe2O4 spinel ferrite.

Influence of Zinc Manganite Nano Fillers on the Optical and Dielectric Features of Poly-Methyl Methacrylate/Multi-Walled Carbon Nanotubes Nanocomposites

Poly (methyl methacrylate, PMMA)/ multi-walled carbon nanotubes (MWCNTs)/ x wt %zinc manganite (ZnMn2O4) polymers were fabricated using co-precipitation and casting techniques. The structure of the filler and all polymers was determined with X-ray diffraction. The morphology of the polymer surfaces was explored by employing scanning electron microscopy. The direct and indirect band gap energies (E g) of PMMA polymer (5.02, 4.44) eV decreased attaining minimum values (4.97, 3.41) eV upon the addition of MWCNTs and 2 wt% ZnMn2O4. The refractive index at 600 nm was increased from 1.33 (PMMA) to 1.55 (x = 2 wt% ZnMn2O4). The optical dielectric constant and optical conductivity displayed their highest values when the ZnMn2O4 doping level reached 2 wt%. The PMMA/MWCNTs/x wt% ZnMn2O4 polymers exhibited blue-violet colors on the CIE 1931 chromaticity diagram under excitation wavelength of 317 nm. The electrical dielectric constant and the AC conductivity attained their peak at the concentration of 2 wt% and 1 wt% ZnMn2O4, respectively. PMMA/MWCNTs/x wt% ZnMn2O4 polymers possess controllable optical and electrical characteristics, thus making them potentially valuable optical materials for future optoelectronic or photocatalytic application development.

Influence of Alkali Oxide on the Characteristics of Copper Sodium-Borate Glass System

Melt quench copper sodium borate glass (75%H3BO3+(25-x)%Cu2O+x%Na2CO3) with x = 5,6,7,8,9,10 was made. Powdered samples were warmed at 300°C for 45 minutes to eliminate moisture, then melted at 950°C for three hours. After annealing at 250°C for 90 minutes, these specimens were polished smooth. We examined how sodium carbonate affects borate glass physical, dielectric, and electrical characteristics. Sample X-ray diffraction was measured using PAN analytical Empyrean diffractometer. XRD data shows the materials are very amorphous. Archimedes calculated density. As Na2CO3 concentration increases, density drops. The density fell from 2.56 to 2.05 g/cm3. Molar volume rose from 31.36 to 38.26 cm3/mole. The glass samples' dielectric characteristics were measured with a 20-Hz-1 MHz LCR meter. The dielectric constant and loss decreased at higher frequencies and peaked at lower applied electric field frequencies. However, AC conductivity was poor at low frequencies and increased with frequency. Electrical characteristics of glass samples at room temperature show linear I-V behavior. FTIR data shows intensity and vibrational band shifts owing to Na2CO3 replacing copper oxide. This modifies borate glass network, causing distinctive differences.

Effect of Cd on Structural, Spectral, Morphological and Dielectric Properties of Sr1-xCdxZn2Fe4O11 R-type Hexaferrites Synthesized via Sol-gel Technique

Sol–gel method was used to prepare Sr1-xCdxZn2Fe4O11 (x = 0.00, 0.02, 0.06, 0.1) R-type hexaferrite. The synthesized materials were sintered at 850oC and desired phase was obtained. X-ray diffraction analysis confirms that R-type hexaferrite exists only as a single phase. Using the Scherer formula, crystallite size for all of the prepared samples was found to be in the range of 10.39–12.62 nm. Crystallite size (D), the lattice parameters (a, c), and the cell volume (Vcell), d-spacing, bulk density, X-ray density, porosity, dislocation density and micro strain were determined in structural analysis. Fourier transform infrared spectroscopy method was used to identify the metal-oxygen vibrations at different locations. FT-IR verifies the presence of the Fe–O stretching vibration band at 743 and 867 cm−1. The typical grain size in surface morphology investigation ranges from 0.56 to 0.82 μm. Dielectric response of ferrite ceramic samples replaced with Cd2+ was investigated in the frequency range of 1 MHz–3 GHz. The AC conductivity rises with an increase in frequency because they are proportional to one another. This increasing tendency is effectively described by the theory of Maxwell-Wagner and Koop. Q-values remain constant as frequency rises and behaves independently of frequency as long as frequency reaches 1.7 GHz. These types of materials are utilized in high-frequency applications including frequency filters and resonant circuits. All of the magnetic properties determined by analyzing the M − H loops, including saturation magnetization (Ms), retentivity (Mr), and coercivity (Hc), exhibit an increasing trend as the substitution of Cd2+ rises. Ms (49.76–56.38 emu/g), Mr (15.82–18.30 emu/g) and Hc range from 203.20 Oe to 215.80 Oe. Grain size decreases cause arise in coercivity, which is caused by an enhancement in magneto-crystalline anisotropy. Overall results suggest that Cd2+ replaced R-type hexagonal ferrites are a great resource for longitudinal recording media; they have the potential to be used in a wide variety of electronic applications, including resonant circuits and high-frequency filters, security, detecting and switching.

A comprehensive study of crystal structure, UV–visible study, electric-dielectric properties of a recently developed Hybrid Material [(C6H5N2)2ZnCl4]

The advanced hybrid material, [(C6H5N2)2ZnCl4] was prepared using the gradual dehydration process by combining 4-cyanopyridine and ZnCl2 under standard ambient temperature conditions. The compound underwent various characterization techniques, including single crystal and Powder X-ray diffractions (SXRD, PXRD), Scanning Electron Microscopy (SEM) and EDX Energy-Dispersive X-ray, FT-IR spectroscopy, UV–Visible absorption analysis, Hirshfeld surface analysis (SHG), and thermal analysis. The molecular composition of the examined chemical substances was determined to belong to the orthorhombic P212121 space group through single crystal X-ray analysis. analysis. Its molecular arrangement was characterized by alternating layers of tetrahedral [ZnCl4]2- and 4-cyanopyridinium planes (C6H5N2)+. These layers are connected through NH···Cl and CH···Cl hydrogen bonds, which contribute to their cohesion and overall adherence. The UV–visible spectrum using Tauc plot relation, has unveiled the energy ratio of an optical band gap, which is measured at 4.80 eV. Additionally, thermal analysis has demonstrated that [(C6H5N2)2ZnCl4] exhibits thermal stability up to a temperature of 475 K. SHG study was employed to examine the interactions between molecules. Additionally, 2D finger plots were utilized to quantitatively assess the impact of these interactions on the crystal structure. This work discusses various electrical characteristics obtained through impedance measurements, including dielectric constants and electric modulus. To shed light on the electrical resistance and dielectric characteristics, we conducted complex impedance spectroscopy at different frequencies with temperature ranging between 313 and 423 K. The elaborate Nyquist curve revealed a solitary semicircle, indicating that the signal was generated by a single capacitive circuit associated with the grain. We also researched ac conduction to figure out how electricity is transmitted. The diagram unveils that the conduction mechanism is thermally activated. The activation energy value obtained from the dc conductivity is approximately 0.768 eV. The analysed material allows for the movement of space charge through a hopping mechanism. Finally, the dielectric constant estimate demonstrates that this title compound is a suitable candidate for the fabrication of opto-electronic materials. Modulus analysis demonstrated that the mobile charge carriers exhibited mobility both at low and high frequencies, covering short and long distances.

Tuning optical, magnetic, and electrical parameters of CuFe2O4 nanoparticles incorporated with GO and ZnO using a facile synthesis

Nano-ferrites, metal oxides, and carbon-based nanomaterials have been used frequently to enhance optical and magnetic prospects for latent applications. Copper ferrite/Graphene Oxide and Zinc Oxide (CuFe2O4/GO/ZnO) ternary nanocomposite synthesized by hydrothermal route showed dramatically good outcomes as the band gap energy value of synthesized nanocomposite approaches to 2.4 eV. Furthermore, the light absorbance of CuFe2O4 increases by adding ZnO and GO. The experimental data revealed the face-centered cubic structure (FCC) of pure spinal ferrite (CuFe2O4) nanoparticles even after adding ZnO and GO. The 2θ peak observed at 31.70° with (220) hkl planes indicates the successful addition of ZnO nanoparticles in CuFe2O4/GO nanocomposite. XRD graph, the absence of characteristic peaks of GO revealed the intercalation of CuFe2O4 nanoparticles with GO layers. In SEM images, agglomeration among CuFe2O4 nanoparticles is observed due to the magnetic interaction of nano-crystallite with a high surface-to-volume (S/V) ratio. VSM can be used to determine the magnetic properties of as-synthesized samples at moderate temperatures under 0–0.5 and ± 5 tesla. In CuFe2O4/GO/ZnO ternary nanocomposite, the saturation magnetization value reduces from 2.071 to 1.365 emu/g due to the addition of ZnO nanoparticles. The loops were narrowed showing a decrease in the coercive field with the addition of ZnO nanoparticles in CuFe2O4/GO ternary nanocomposite material. Moreover, the study of electrical properties of pure CuFe2O4 and CuFe2O4/GO/ZnO ternary nanocomposite revealed that the values of dielectric constant and tangent loss decrease at high frequencies owing to surface charge polarization and intrinsic dipole interactions. The study of the electrical properties of both pure CuFe2O4 and the CuFe2O4/GO/ZnO ternary nanocomposite reveals that the dielectric constant (ε’) and tangent loss (tanδ) exhibit a decreasing trend as the frequency increases. This behavior is attributed to surface charge polarization and intrinsic dipole interactions. At lower frequencies, both samples display elevated values for these properties, which stabilize as the frequency increases beyond 2 MHz. Notably, high AC conductivity is observed in both samples, attributed to increased capacitance and resistance.

Facile design of a low-cost laser CUT-OFF filter with PMMA polymer nanocomposite doped with Mg0.5Ni0.5Fe2O4: structural, optical, and dielectric properties

This study employed the sol gel auto-combustion approach to synthesize Mg0.5Ni0.5Fe2O4 spinel ferrite nanoparticles. Additionally, the casting method was used to fabricate Mg0.5Ni0.5Fe2O4/PMMA nanocomposite polymer films. The structural properties were analyzed by the utilization of x-ray diffraction pattern (XRD), high resolution transmission electron microscope (HRTEM), and field emission scanning electron microscope (FESEM). The UV-visible spectrophotometer examination was used to evaluate the optical properties of the produced nanocomposite films, such as absorbance, transmittance, indirect energy band gap, Urbach energy, excitation coefficient, and refractive index. Two indirect optical energy gaps are calculated, whereas they decreased from 4.56 eV to 4.33 eV, and from 4.04 eV to 3.01 eV, while the Urbach energy increased from 0.304 eV to 0.524 eV as the nanofillers increased from 0 to 4 wt%. An investigation was conducted to examine the impact of nanoparticle doping on the dielectric constant, electric modulus, and ac conductivity. The Mg0.5Ni0.5Fe2O4/PMMA nanocomposite films demonstrate higher permittivity and ac conductivity and a lower dissipation factor and electric modulus compared to pure PMMA. The dielectric permittivity (ε′) increased from 2.76 to 3.43 at a constant frequency 100 Hz up to 2 wt.% of Mg0.5Ni0.5Fe2O4 then decreased to 2.41 while the dissipation factor tan(δ) decreased from 0.1 to 0.046 at the same frequency. The nanocomposite films are well-suited for utilization in CUT-OFF selective laser filters, solar cells, energy storage devices, and other applications in related industries.

High photocatalytic degradation of methylene blue and enhancing the magnetization, AC conductivity of Dy3+ and Ce3+ doped CdCoFe2O4 nano ferrites

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd0.4Co0.6DyXCeXFe2-2XO4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs.

Dielectric Characterization and Machine Learning-Based Predictions in Polymer Composites with Mixed Nanoparticles

Our research described in this manuscript investigated the dielectric properties and structural characteristics of Bisphenol-A epoxy resin composites infused with various concentrations (5 wt.%, 10 wt.%, and 15 wt.%) of hybrid nanofillers, namely alumina (Al2O3) and zinc oxide (ZnO). Ultrasonic dispersion was utilized to integrate the nanofillers into the resin matrix. Structural properties were assessed using X-ray diffraction (XRD), which confirmed the presence of the Al2O3 and ZnO nanoparticles within the epoxy matrix. Dielectric properties were measured over a frequency range of 104 Hz to 2 MHz. The results provide new insights into the polarization mechanisms and structural characteristics of these composites, highlighting their potential for enhanced dielectric performance in high-frequency applications. To further understand and predict these dielectric properties, the CatBoost and LightGBM regression models were employed to predict the dielectric constant (ε'), loss tangent (tan δ), and AC conductivity (σac) of these composites. The models demonstrated strong predictive accuracy, with performance metrics, including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R-squared (R2), indicating the robustness and accuracy of the models in predicting the dielectric properties of the composites. The study’s findings underscore the significant potential of Bisphenol-A epoxy resin composites with hybrid nanofillers for high-frequency dielectric applications.

Enhanced ionic conductivity through B-site Zr doping in NaNbO3 solid electrolytes

Oxide ion conductors hold significance in various applications, such as electrolytes in solid oxide fuel cells. This study focuses on synthesizing and systematically investigating the structural, morphological, and electrical properties of NaNb1-xZrxO3-0.5x (0 ≤ x ≤ 0.15) solid electrolyte. X-ray photoelectron spectroscopy (XPS) analysis shows that introducing a small quantity of zirconium into NaNbO3 induces an environment of unbalanced charge neutrality, creating oxygen vacancies. This phenomenon establishes a pathway for the mobility of oxygen ions. Temperature-dependent ac conductivity, analyzed through impedance data, follows Jonscher's power law, with the 's' parameter indicating a correlated barrier hopping mechanism. Enhanced conductivity is observed with Nb5+ substitution by Zr4+. The reduced activation energy value is observed for x = 0.1, which suggests enhanced ion hopping and, hence, enhanced conductivity. NaNb0.9Zr0.1O2.95 exhibits predominantly ionic conduction with a total conductivity of 6.2 × 10−4 S cm−1 and bulk conductivity of 1.72 × 10−3 S cm−1 at 700 °C. This study shows the promising potential of Zr-doped NaNbO3 as a solid electrolyte for various electrochemical applications.

Investigation of electro-optical and dielectric properties of pure and dispersed nematic liquid-crystal

ABSTRACT In this study, 4-(Trans-4ʹ-n-Pentylcyclohexyl) Benzonitrile (PCH5) has been employed as a host liquid crystal (LC) to disperse carbon quantum dots (CQDs). The investigation delves into the dielectric behaviour and electro-optical properties of dispersed nematic systems featuring both pure and CQD-incorporated compositions. We examined the impact of CQD dispersion on various parameters such as relative permittivity, dielectric loss, AC conductivity, birefringence, and threshold voltage in the nematic liquid crystal (NLC) PCH5 at concentrations of 0.1, 0.3, and 0.5 wt%. These properties demonstrate notable changes upon the addition of CQDs to the nematic PCH5 system, influenced by both the dopant concentration and the applied electric field. Birefringence, determined using the transmittance method, reveals higher values in dispersed systems, influenced by factors such as dopant concentration, temperature range, and chemical composition. Furthermore, the composite systems with dispersed CQDs exhibit significantly reduced threshold voltages. The observed findings are attributed to the interactions between CQDs and nematic molecules. Also, we explored potential applications for the dispersed systems investigated in this study.

Improved magnetic, electrical, and dielectric characteristics of graphene nano-platelets (GNPs)-Integrated Ni0·4Cd0·6Fe1.97Sm0.03O4 ferrite composites synthesized via sol-gel auto-combustion method

This research work analyzes the impact of graphene nanoplatelets (GNPs) on the structural, electrical, dielectric, optical, and magnetic properties of the Ni0·4Cd0·6Fe1.97Sm0.03O4/x-GNPs (SNCF/GNPs) composites (x = 0 %, 2.5 %, and 5 %) prepared via the sol-gel auto-combustion route. The results revealed that SNCF particles were distributed on GNPs which improved the multifaceted properties of SNCF spinel ferrites. XRD analysis confirmed the FCC spinel structure with a minimum crystallite size (D) of 18.99 nm for sample with 5 wt %GNPs. The DC electrical resistivity decreased from 9.06 × 1011 Ω-cm at 313K to 1.41 × 108 Ω-cm at 673K, revealing the semi-conducting nature of composites. The improved electroconductivity and reduced bandgap energy are observed for samples with minimum resistivity 1.02 × 105 Ω-cm at 673K and 1.70 eV energy, respectively, containing 5 wt %GNPs. Samples show higher permittivity values at low frequency and decreased at high frequency. The maximum ac conductivity is observed for composite with 5 wt %GNPs which is attributed to the hopping mechanism. Finally, the magnetization (Ms) increased from 52.24 to 79.71 emu/g with increasing GNPs contents. Hence, the synthesized composites with 5 wt %GNPs are more favorable than the pure sample for application in waste-water treatment, high-frequency devices, and energy storage devices.

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.