Ac Conductivity Values Research Articles

Investigation of the Dielectric Characteristics of Chromium-substituted Zinc and Cobalt Nanoferrite Systems

Abstract The series of Cr-substituted Zn and Co nanoferrite systems having the chemical composition CrxZnFe2–xO4 and CrxCoFe2–xO4 (0.0 ≤ x ≤0.5) were prepared by sol–gel technique. The present investigation aims to compare the impact of Cr3+ concentration on dielectric characteristics of Zn and Co-nanoferrite systems. The investigation of various dielectric characteristics was conducted using an LCR meter at 1kHz frequency and across the frequency range of 100Hz to 1MHz. The measurements were conducted at room temperature. In the case of both ferrite systems, the plots of frequency Vs dielectric constant (ε′) and AC conductivity (σac) show a common dielectric behavior of spinel ferrites. The plots of frequency Vs dissipation factor (D) of Cr- Cr-substituted zinc and Cobalt nanoferrite samples were observed to be unusual and display a relaxation peak at a particular frequency. In the current study, CrxZnFe2-xO4(x=0.2 and 0.3) and CrxCoFe2–xO4 (x=0.3) ferrite samples were found to exhibit very high values of dielectric constant. So these ferrites may be useful for a wide range of applications in electrical storage devices. According to LCR reports, all the Cr3+ substituted ferrite samples in both ferrite systems exhibit higher dielectric constant and AC conductivity values. Possible mechanisms that may be accountable for the outcomes are thoroughly scrutinized in this paper.

Impact of TBAI Doping on the Optical and Dielectric Features of PVC/MoO3/NiMoO4/PANI Polymer Composite for Optoelectronic and Energy Storage Applications

Poly (vinyl chloride, PVC)/MoO3/NiMoO4/polyaniline (PANI)/x wt% tetrabutylammonium iodide (TBAI) polymers were formed using casting and hydrothermal methods. The present study examined the nanocomposites’ structural, electrical, and optical features comprising PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers. X-ray diffraction and scanning electron microscopy were used to investigate the structure and morphology of different samples. The influence of different amounts of TBAI on the linear and nonlinear optical features of PVC/MoO3/NiMoO4/PANI/x wt%TBAI polymers was explored. Adding MoO3/NiMoO4/PANI.TBAI reduced the direct and indirect optical band gaps to their minimum values (3.88, 3.04) eV and (3.58, 2.13) eV, respectively. Doped polymer with MoO3/NiMoO4 has the highest refractive index value. Only PVC filled with MoO3/NiMoO4 exhibits the highest non-linear optical parameters within the visible range. The fluorescence intensity and emitted colors influenced by the kind of dopant. The dielectric constant and ac conductivity values of the host polymer were affected by the amount of TBAI. The maximum energy density value was observed in PVC/MoO3/NiMoO4/PANI/10 wt%TBAI polymer. The Cole-Cole plot demonstrated an irregular shift for doped samples relative to the undoped. The obtained results nominated the nanocomposite films of PVC/MoO3/NiMoO4/PANI/x wt%TBAI to be used in diverse electric and optoelectrical applications.

Enhancement of the thermal, electrical properties and mechanical properties of graphene doped novel copolymers bearing coumarin side groups

In this study, a new monomer 3-acetyl coumarin-7-ylacrylate (Ac-Kum) was synthesized. A series of copolymer were prepared by using (Ac-Kum) and methyl methacrylate (MMA) in different ratios. The structure characterization of the compounds was carried out by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Graphene doped polymer composites were prepared at different rates (1%, 2% and 5%). The thermal behavior of the polymer composites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) methods. Thermal stability of 1%, 2% and 5% graphene composites of homopolymer was determined as 324 °C, 345 °C and 350 °C, respectively. The dielectric properties of the polymer composites were investigated as a function of frequency. Dielectric constant, dielectric loss and ac conductivity values of homopolymer were determined as 6.13, 0.11, 1.02×10−09 S/cm and 5% graphene composite were determined 49.30, 7259, 9.26×10−07, respectively. Microhardness tests were carried out under a load of 100 g and in 10 seconds. The microhardness values were calculated by taking the average of the microhardness values taken from the surface of the samples from five different points. The highest microhardness value is the 5% graphene added P(Ac-Kum) sample. Wear tests were carried out with a pin-on-disc wear tester under single load (10N) and in dry conditions with a total sliding distance of 10 meters and a sliding speed of 5 mm/sec. Disc samples with a diameter of 13 mm were placed in the sample holder part of the test device. The highest wear resistance sample is the P(Ac-Kum) 5% graphene composite.

Tweaking the structural, micro–structural, optical and dielectric properties of anatase titanium dioxide via doping of nitrogen ions

The pure nanostructured anatase titanium dioxide (TiO2) and subsequent nitrogen–doped derivatives (TiO2–xNx; where, x = 0.005, 0.01, 0.05) were synthesized by sol–gel auto–combustion technique. XRD analysis confirms the formation of pure anatase phase of TiO2 up to doping of 1 mol% (x = 0.01) of nitrogen having tetragonal structure with space group of I41/amd whereas an additional monoclinic phase of TiO2–B was observed at 5 mol% of nitrogen doping in TiO2. This sample has smallest crystallite size of ∼4.7 ± 0.2 nm corresponding to TiO2–B phase and ∼12.0 ± 0.1 nm corresponding to anatase phase. XRD also reveals that the crystallite size of all other samples having pure anatase phase ranges between ∼8.7 ± 0.1 nm & 13.9 ± 0.1 nm. The crystalline phase revealed from XRD of all samples was further supported by the Raman analysis. The direct optical band gap of pure TiO2 (∼3.4 eV) was reduced non–monotonically after nitrogen doping in the ranges from ∼2.8 eV (TiO1.95N0.05) to ∼2.0 eV (TiO1.99N0.01). FTIR spectra confirm the metal oxide bond formation, surface adsorption of water molecules and presence of residual hydroxyl group in all crystalline samples. HRTEM analysis validates the coexistence of secondary phase of TiO2–B along with anatase phase of TiO2 in studied highest doped sample (TiO1.95N0.05) including its broader particle size distribution as compared to pure TiO2. The electrical studies reveal that the highest values of dielectric constant and ac conductivity can be realized for pure TiO2 and at 1 mol% (x = 0.01) of nitrogen doping, among all the studied nitrogen doped samples.

Si/ZnO:Coumarin photocapacitor for electro and photonic applications

The present study first investigated the photocapacitance measurements of Al/p-Si/ZnO:Coumarin/Au metal-oxide-semiconductor MOS device at room temperature in the frequency range of 10 kHz-1MHz and bias voltage range of −5 V; +5 V. Based on photocapacitance analysis, Vbi, Na, Nss, Ef, Em, Δϕb, ϕb, Wd values were calculated for 10 kHz, 100 kHz and 1 MHz. For 1 MHz, Vbi value was 0.79 eV, Na value was 3.54x1015 cm−3, ϕb value was 0.99 eV and Wd value was 530 nm. Additionally, the dielectric constant (ε′), dielectric loss (ε″), electrical modulus (M′M″) and complex impedance (Z*), tangent loss (tanδ), ac conductivity(σac) and phase angle (φ) values of the device were also calculated. ε′ values were calculated 116 at 10 kHz, 58 at 100 kHz and 6 at 1 MHz. These ε′values indicate that the higher ZnO:Coumarin layer can store more charge carriers. This study has shown that materials produced by ZnO, a metal oxide semiconductor, doped with coumarin have the potential to be used in many optoelectronic devices, especially in photonic applications.

Influence of ZnMn2O4/CuCo2O4 nano-fillers on the optical and electrical properties PVA/CMC/PEG blended polymers

(1-x)ZnMn2O4/xCuCo2O4 samples were synthesized by the co-precipitation method while polyvinyl alcohol/carboxymethyl cellulose/polyethylene glycol (PVA/CMC/PEG) blended polymer were fabricated by the casting method. Rietveld refinement analysis was used to determine the crystallite size and phase percentages for each composition were determined for all samples. The morphology and structure of PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends were examined using scanning electron microscopy and x-ray diffraction techniques. The reflectance and transmittance spectra were examined for blended polymers using a diffused reflectance spectrophotometer. Using LCR meter, the prepared blend films' dielectric properties were evaluated. When the blend is loaded with 0.9ZnMn2O4/0.1CuCo2O4, the lowest transmittance values (29–47 %) in the visible region are reached. As the CuCo2O4 doping levels became 10 % in the filler, the smallest direct and indirect energy gap values of 5.4 and (4.47, 1.9, 1.65) eV were attained, respectively. The linear and nonlinear optical parameters affected by the amount of CuCo2O4 in the filler samples. The optical conductivity of the doped blend reached its maximum value at x = 0.15. The CIE chromaticity diagrams revealed that the blends have varying degrees of blue color. The addition of (1-x)ZnMn2O4/xCuCo2O4 fillers improves the energy storage capability of the blends without raising the energy dissipation. The highest value of AC conductivity was achieved with the blend containing 0.9ZnMn2O4/0.1CuCo2O4. Nyquist plot revealed that the ionic conductivity increased as a result of doping. The obtained results suggest that the doped PVA/CMC/PEG/(1-x)ZnMn2O4/xCuCo2O4 blends might be used in a variety of industrial applications, including solar cell technology.

PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers: Improved the physical properties for energy storage devices and optoelectronic applications

The current investigation aims to enhance the optical and dielectric properties of poly (vinyl alcohol) (PVA)/polyethylene glycol (PEG) blended polymers via loading with copper cobaltite (CuCo2O4), polyaniline (PANi), and x wt% multi-walled carbon nanotubes (MWCNTs) for potential applications in optoelectronics and capacitive storage. The fabrication of PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers was carried out via casting and hydrothermal methods. Characterization of the blended polymer's structure and morphology was conducted using X-ray diffraction and scanning electron microscopy techniques. The impact of various fillers on the linear and nonlinear optical properties of the host blend was analyzed. The loaded blends demonstrated efficacy in blocking UVA, UVB, and UVC spectra, making them suitable absorbers for solar cells. The lowest values for direct and indirect optical band gap energy (Eg), of 5.34 eV and 4.44 eV were attained at x = 0.02. The blend with x = 0.01 displays the highest refractive index at λ = 600 nm. The optical conductivity exhibited nonmonotonically growth until peaking at x = 0.01. Analysis of chromaticity diagrams in CIE 1931 color space reveals that all blends emit blue-violet hues with slight variations in intensity. The fluorescence (FL) intensity of the doped blend is notably lower compared to the undoped counterparts. The doped blend (x = 0.03) showcases superior dielectric constants and ac conductivity values. The maximum energy density was achieved at 1 kHz for the host blend incorporating CuCo2O4/PANi. Overall, the observed characteristics indicate that PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers represent promising hybrid nanomaterials suitable for diverse applications.

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.

Structural, optical, and dielectric properties of aminated PMMA/GO polymer nanocomposite for storage device applications

A series of aminated PMMA/GO polymer nanocomposite (PNG) were synthesized by solution mixing in two step process. The synthesized PNG samples were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning Electron Microscope (SEM), energy dispersive X-ray analysis (EDAX), Thermo-gravimetric, differential thermal analysis (TG-DTA), UV–Visible spectroscopy (UV–Vis) and impedance spectroscopy. The X-ray diffraction (XRD) data indicated the existence of crystalline nature in PMMA and the reduction of graphene oxide (GO) which is also confirmed by TGA and DTA results. The interaction between graphene oxide nanoparticles and the functionalized polymer matrix has been validated using FTIR investigations. The SEM and EDAX measurements demonstrated the homogeneous dispersion of graphene oxide (GO) over the surface of the produced samples. The UV–Vis spectroscopy analysis revealed that the optical energy gap values of nano composites decrease as the amount of graphene oxide nanoparticles increases. All samples exhibited higher relative permittivity at low frequencies which is a key factor for high energy density. As the concentration of GO increases, the maximum peak of dielectric loss tangent also shifted to higher frequency due to increase in interfaces. The β relaxation is dominant in non-polar PMMA due to the functionalisation and dispersion of GO. The AC conductivity values increased with increase in concentration of GO. The single semicircle in plot from impedance spectroscopy and the drop in bulk resistance values of PNG samples made them as a good material for energy storage devices like supercapacitors.

Co-Ni spinel nanoparticles for energy storage applications: Composition, structural parameters and electrical properties

In the ambit of this investigation, we delved into the properties of (Co/Ni)Fe2O4 spinel nanoparticles (CNSNs) with a spectrum of Co/Ni ratios, delineated as Co1-xNixFe2O4, where x adopts values of 0.0, 0.3, 0.5, 0.7 and 1.0. The synthesis of these CNSNs was adeptly executed via the citrate precursor technique. This study meticulously examined the crystal structure and granular morphology by applying X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was unequivocally determined that each specimen exhibited a homogenous phase. The lattice parameters for the synthesized CNSN compounds agreed with the mean ionic radii of the Co2+ and Ni2+ ions, mirroring their respective concentrations within the nanoparticles. Furthermore, an extensive analysis of the alternating current (AC) electrical properties was carried out, encompassing a broad frequency range from 1 kHz to 3 MHz and a wide temperature range from 303 to 423 K. The observed behavior of the electrical properties was thoroughly evaluated and elucidated, considering the chemical composition of each CNSN. The relationship between the frequency dependency of σac, έ and tanδ is congruent with the prevailing literature and theoretical constructs that elucidate the composite materials' conductivity and dielectric constant, comprising grains and grain boundaries. The present CNSN samples do not exhibit maximum peak for tanδ, potentially due to the wider range of frequencies used than the anticipated peak frequency. The samples' measured conductivity and dielectric constant values displayed a high degree of coherence, corroborating each other's findings. Literature corroborates that the escalation in ac-conductivity values with frequency intimates certainly that the prepared samples may herald promise for utilization in energy storage solutions, bolstering the synergistic efficacy observed. Another conceivable application of these CNSN materials could be their integration in microwave technologies, suggesting a broad scope for future technological advancements.

Enhancing the Conductivity and Dielectric Characteristics of Bismuth Oxyiodide via Activated Carbon Doping.

Activated carbon/BiOI nanocomposites were successfully synthesized through a simplistic method. The produced composites were then characterized using XRD, TEM, SEM-EDX, and XPS. The results showed that BiOI with a tetragonal crystal structure had been formed. The interaction between activated carbon and BiOI was confirmed via all the mentioned tools. The obtained nanocomposites' electrical conductivity, dielectric properties, and Ac impedance were studied at 59 KHz-1.29 MHz. AC and dc conductivities were studied at temperatures between 303 and 573 K within the frequency range of 59 KHz-1.29 MHz. The 10% activated carbon/BiOI nanocomposite possessed dc and AC conductivity values of 5.56 × 10-4 and 2.86 × 10-4 Ω-1.cm-1, respectively, which were higher than BiOI and the other nanocomposites. Every sample exhibited increased electrical conductivity values as the temperature and frequency rose, suggesting that all samples had semiconducting behavior. The loss and dielectric constants (ε' and ε″) also dropped as the frequency increased, leading to higher dielectric loss. The Nyquist plot unraveled single semicircle arcs and a decreased bulk resistance, indicating decreased grain boundary resistance. Consequently, the electrical characteristics of BiOI, 1C/BiOI, 5C/BiOI, and 10C/BiOI implied their applicability as dielectric absorbers, charge-stored capacitors, and high-frequency microwave devices.

Investigating and characterizing electrical properties of polypyrrole/SiO2/FePS3 nanocomposite

AbstractNovel nanocomposites of polypyrrole (PPy) embedded in silica (SiO2) and iron phosphorus trisulphide (FePS3) nanoparticles have been fabricated. The nanocomposite's dielectric characteristics have been examined in relation to temperature ranges of 25–200°C and frequency ranges of 0.1–7 MHz. Fourier‐transform infrared spectroscopy (FTIR), x‐ray diffraction (XRD), scanning electron microscopy (SEM–EDX), transmission electron microscope (TEM), and dielectric measurements have all been used to evaluate the prepared nanocomposite. The monoclinic crystal structure of the prepared FePS3 and PPy/SiO2/FePS3 nanocomposite is confirmed by XRD, EDX, and TEM studies. The FePS3 is perfectly layered structure in the SEM image, and FePS3 and SiO2 particles are well intercalated, creating novel nanocomposites of two nanoparticle phases that served as a union network during the polymerization process. The IR spectrum shows that PPy is a dopant in the interlayer area of FePS3. The splitting major peak (570 cm−1) of FePS3 is visible at around 640 and 560 cm−1. The high AC conductivity values indicated that the combination of FePS3/SiO2 nano‐matrix contains PPy at high packing densities and confirming the semiconducting properties of the nanocomposite to be used in several electronic applications.

Investigation of the effect of graphene oxide nanoparticles on the structural and dielectric parameters in zinc oxide semiconductors

In this study, pure and 1%, 3% and 5% doped graphene oxide (GO) reinforced zinc oxide (ZnO) nanoparticles were synthesized by sol-gel method. The aim was to improve the electrical and dielectric properties of ZnO semiconductor metal oxide used in many electronic, optoelectronic and electrochemical technologies. FE-SEM, X-ray diffraction (XRD), Raman spectroscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy (FT-IR), were used to show the structural and morphological properties of the synthesized ZnO and GO doped ZnO nanoparticles. Impedance analysis was used to study the dielectric properties of the produced nanoparticles. XRD analysis revealed typical peaks of nGO and ZnO nanoparticles. Through the FE-SEM and XRD analysis, it was shown that the ZnO and GO nanopowders were successfully synthesized. The results revealed that ZnO-GO nanoparticles, having good dielectric constant with loss and AC conductivity values, such materials can be a good candidate for solar cells and photovoltaic devices.Graphical

Influence of Congored on the Optical, Dielectric and Thermal Behavior of Polymethyl Methacrylate and Polyvinyl Chloride

Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc’s model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR.

Experimental and Theoretical Realization of Morphology and Frequency Tuned Charge Transport Dynamics in Co-Zn Doped SrM Hexaferrite: Electrical, Impedance and Relaxation Realm

The present report comprehensively investigates the influence of sol-gel synthesized cobalt and zinc-substituted SrFe12O19 on the morphological, structural, dielectric, and electrical characteristics. XRD analysis revealed that the substituents successfully replaced Fe3+ ions, leading to the existence of magneto-plumbite structure of M-type hexaferrite in all synthesized samples with some minor traces of CoFe2O4 in Sr Co0.8Zn0.8Fe10.4O19. With increasing the substitution level, SEM micrographs exhibited the formation of grain clusters. The electrical parameters had been investigated in the 20 Hz to 2 MHz frequency range. In the low-frequency region, both dielectric constant and loss tangent decreased with Co-Zn substitution. Sr Co0.8Zn0.8Fe10.4O19 sample shows the minimum value of AC conductivity 3.95 × 10−5 Ω−1m−1 in the high-frequency region. Both the electric modulus and impedance spectra exhibit non-Debye behavior in all samples. The Cole-Cole plots ( M'' versus M') reveal the existence of a single semicircular arc in the x = 0.0 sample, caused by the grain boundary contribution.

Collegial effects of CeO2/SiC nano-fillers on dielectric, thermal, impedance and conductivity behavior of PVDF-HFP matrix for flexible energy storage applications

ABSTRACT In the current study, novel Poly(vinylidene fluoride-co-hexafluoropropylene)/Cerium oxide/Silica carbide (PVDF-HFP/CeO2/SiC) flexible polymer nanocomposites were synthesized by solution casting technique. Structural changes involved in the composite formation between nano-fillers and host polymers were analyzed by X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. SEM results confirm the homogeneous dispersion of nano-fillers (CeO2 & SiC) within the host polymer. Thermogravimetric analysis (TGA) was used to identify the thermal stability of the polymer nanocomposite with about 56% of residual residue for increased nano-fillers loading. Tauc plots confirm that the energy band gap of pristine host polymer decreased with the incorporation of nano-fillers. The dielectrics, impedance, and AC conductivity studies were investigated in temperature ranging from 50°C to 150°C and the frequency range between 50 Hz and 10 MHz measured by an impedance analyzer. As a function of nano-filler loading, the nanocomposites show a significant increase in the dielectric constant (ε′ = 272.92, 50 Hz, 50°C) with low dielectric loss (tan(δ) = 1.98, 50 Hz, 150°C) values. Impedance and the AC conductivity results suggested that addition of nano-filler decreases the impedance and improves the AC conductivity value from 1.67 × 10−4 S/m for pristine PVDF-HFP to 1.44×10−3S/m for 15% SiC. These results justify the material being efficiently applicable for flexible energy storage applications.

Room temperature AC electrical, surface micro texture analysis, microwave permittivity and dielectric loss tangent in ZnO films doped by Cu, Al, and CuAl

The purpose of this work is the study of the correlation between the thickness of ZnO films doped by transition metals and their three-dimensional (3D) micromorphology. The as deposited ZnO films became more irregular surface hence the maximum value of Sq belong to as deposited ZnO films was in a bout of 0.1038 mm. The core roughness height Sk calculated as a difference between two extreme levels (maximal and minimal) of surface core, for ZnO films annealed at 500 °C have maximum value in a bout of 0.7325 mm. Since the surface kurtosis (Sku) of all sample's films were above 7, therefore there were high peaks or valleys on the films surface and for as deposited CAZO films with value of with 8.883. The height distribution histograms shown that as deposited films respect to annealed films have more uniform distributions. The AZO films annealed at 500 °C have maximum value of DC conductivity in about 104.167 S cm−1. The value of log (dielectric loss tan(δ)) in AZO films have maximum value in range 0.05–0.15. As the frequency of incident photons were increased the polarization orientation were increased. Log AC conductivity values of films were shown almost linear behavior with increasing incident photons frequency that indicates conduction hopping is followed by a small polaron mechanism. AC conductivity values of as deposited AZO films in all frequencies have maximum value.

Electrical conductivity and significant radiation shielding properties of B2O3.Pb3O4.ZnO.Y2O3 glasses

The electrical properties and radiation shielding characteristics are investigated for a glass system of the configuration 60% B2O3-35% Pb3O4-(5-x)%ZnO - x%Y2O3 with x from 0 to 3 mol%. Frequencies from 100 Hz to 5 MHz were applied to measure the ac conductivity in a temperature range between 310 and 700K. The values of ac conductivity (σac) are found in the range from 2×10−9 S.cm−1 to 5×10−2 S.cm−1, while the activation energy for ac conductivity (Eac) is found to fluctuate between 0.4 and 1.43 eV. The dc conductivity (σdc) and dc activation energy (Edc) are discussed according to thermal activation and small polaron hopping mechanisms. An alternation from mainly electronic to mainly ionic conduction mechanism is evidenced for the samples greater than 2% mol of the Y2O3. The radiation shielding characteristics are studied in wise of mass attenuation coefficient, μ/ρ, effective atomic number, Zeff, half value layer (HVL), and mean free path (MFP). The values of μ/ρ are obtained experimentally and theoretically by Phy-X/PSD software. The obtained relative deviation between theoretical and experimental results lies in the range from 0 to 3.8%. All the shielding factors demonstrate an inverse reliance on the Y2O3 content in the glasses. The MFP and HVL magnitudes of the glasses are compared with other traditional shielding materials and presented better attenuation ability. The relation between the shielding parameters and the electrical properties is discussed and it is also found that both properties are strongly affected by the interionic separations between the Pb ions in the glasses.

The effects of 4% barium doping on the morphological, strutural and dielectric characteristics of (Na0.5 Bi0.5)[(Ti0.8 Zr0.2)0.9(Nb2/3 Zn1/3)0.1]O3

In this study, perovskite ceramics (Na0.5 Bi0.5)1-xBax[(Ti0.8 Zr0.2)0.9(Nb2/3 Zn1/3)0.1]O3 (NB1- xBxTZNZ) were prepared using the molten salt method. The sintering process was conducted at 1100°C for 4 hours in an air atmosphere. The crystal structure was examined using X-ray powder diffraction, which indicated that the material crystallized in a tetragonal structure with a space groupe P4bm. However, there was also evidence of 6% pyrochlore phase present. The crystallite size was found to decrease with Barium doping, and this decrease was attributed to the pinning effect of grain boundaries resulting from the formation of oxygen vacancies which reduce the AC conductivity values. Scanning electron microscopy was employed to examine the grain morphologies, revealing that the sample exhibited a compact structure. Additionally, the density of (NB1-xBxTZNZ) (x=0.04) was observed to be higher compared to (NB1-xBxTZNZ) (x=0.00). Barium doped into NB1-xBxTZNZ also caused a decrease in dielectric constant and dielectric loss. Raman spectroscopy was performed at room temperature on the doped ceramic with Barium, and we discussed the incorporation of Ba2+ in A-site of the perovskite ABO3.

Investigation of electrical, dielectric, and relaxation phenomenon of Co–Cr substituted SrM hexaferrite: Validation of measured and simulated parameters

Chromium (Cr) and Cobalt (Co) substituted hexaferrite with composition Sr(CoCr)xFe(12−2x)O19 (x=0.0to 0.6) has been synthesized via the Sol-gel combustion technique. The phase purity, morphology, and electrical characteristics of all sintered hexaferrite have been analyzed. XRD measurements showed that all sintered hexaferrite exhibit a magnetoplumbite structure. The substitution of Cr–Co ions in a crystal lattice resulted in a meager decrease in lattice constant value ‘a’ and a considerable decrease in lattice constant value ‘c’. FTIR spectra revealed the existence of three precise absorption bands at 419.59, 539.71, and 580.37 cm−1 which were predicted to be due to Fe–O vibrations. Impedance spectroscopy has been carried out on a wide range of frequencies (20 Hz–2 MHz). The investigated parameters have been considerably affected by dopant-tuned morphology through a decrease in grain size and the formation of grain clusters. The loss tangent and dielectric constant of the Cr–Co substituted SrM hexaferrite is found to be increased with substitution. Substitution causes a decrease in the AC conductivity value in the high-frequency region from 9.57 × 10−4 to 3.05 × 10−4 Ω−1m−1. The non-Debye behavior is observed in the material by analyzing the dielectric and electric modulus spectra. The simultaneous contribution of grain/grain boundaries demonstrated by Cole-Cole plots (M″ vs M′) in the x = 0.4 sample is consistent with SEM micrographs. The charge transport mechanism that occurs in the synthesized samples can be explained with SEM/FESEM micrographs as well as with calculated values of grain and grain boundary resistance/capacitance from EIS software. The two incomplete semicircular arcs have been observed in the x = 0.6 sample in Z″ vs Z′ plots. The conductivity relaxation is significantly improved with Cr–Co substitution.