Dependent Ac Conductivity Research Articles

Preparation, structural, electrical, and ferroelectric properties of solid and lead zirconium titanate ink

The novelty of the work lies in the design and development of a significantly low-cost lead zirconate titanate (PZT) ink similar in its electrical properties to its original solid materials, which can be used for 3-D printing to print electronic circuits, shape memory, and devices quickly. The Zr/Ti=52/48 ratio was achieved during the solid-state reaction to create the PZT powder. XRD, FT-IR, and SEM characterized the synthesized material. The PZT powder was found to form in a tetragonal phase. The PZT powder was used to prepare PZT ink with a 13 % Wt/Wt solid content composition. The ink's rheological characteristics and physical properties, such as particle size distribution, surface tension, viscosity, and electrical properties, were studied. Dielectric properties like dielectric constant (ε/) and dielectric loss (ε") indicate the poly-dispersive nature of the material. The temperature-dependent dielectric constant (ε/) curve indicates relaxor behavior with a maximum at high temperatures. The poly-dispersive nature of the material was analyzed using Cole-Cole plots. The frequency dependence of AC conductivity follows the universal power law. The temperature dependence of dc-conductivity follows the Arrhenius law, with an activation energy of 0.14 eV at lower temperatures and 0.85 eV at higher temperatures. The electrical conductance study showed that PZT ceramic can be used in electronic circuits because of its high resistivity value and small temperature coefficient of resistance. The piezoelectric measurement displays d33 as 129 pC/N at room temperature.

Crystal structure, thermal behavior and electric properties of a new semiconductor cobalt-based hybrid material

The crystals of the new organic-inorganic hybrid material, (C5H12N)2[CoBr2.73Cl1.27], were successfully synthesized by the slow evaporation method and characterized by single-crystal X-ray diffraction, thermal analysis, UV–Vis absorption and electrical measurements. This compound crystallizes in the centrosymmetric space group P21/n of the monoclinic system with unit cell parameters: a = 9.7724 (6) Å, b = 12.3920 (6) Å, c = 15.0307 (9) Å, β = 100.864(6) °, V = 1787.59(18) Å3 and Z = 4. The IR spectrum of the compound is studied, especially for the cationic vibrational part. The thermal analysis indicates that (C5H12N)2[CoBr2.73Cl1.27] is stable up to 270 °C and that it undergoes two reversible phase transitions at 152 and 187 °C and at 141 and 128 °C on heating and cooling, respectively. From UV visible gap energy value of 3 eV it can be concluded that the new mixed halide compound is a semiconductor material. The electrical behavior of (C5H12N)2[CoBr2.73Cl1.27] was studied using impedance spectroscopy in the temperature range of 323 to 403 K. According to a study on the frequency dependence of ac conductivity, the material follows Jonscher's universal dynamic law with an increase in the frequency exponent (s) as temperature increases. This behavior reveals that the conduction mechanism is the nonoverlapping small polaron tunneling (NSPT) model.

Conduction and Dielectric Behaviors of Ge16Se52Te32-xSbx(x = 0,2,4,6,8) glassy system

The quaternary antimony substituted Ge-Se-Te glasses have been synthesized using melt quench technique. The ac conductivity and dielectric properties viz. dielectric constant and dielectric loss of pallets has been studied in the frequency range (500Hz-1MHz) from room temperature to 365K. Both ac conductivity and dielectric properties are found to have dependence on frequency and temperature. The ac conductivity is found to obey the power law ωs, where s approaches unity at room temperature and decreases with increase in temperature. The temperature dependence of ac conductivity has been explained on the basis of relaxation caused by the motion of electrons or atoms and the correlated barrier hopping (CBH) model. The dielectric constant and dielectric loss are found to increase with temperature and decrease with the frequency. The variation of the studied properties with Sb content has also been investigated for all the compositions.

Insight into OLPT model conduction mechanism and dielectric relaxation of lead borate glass containing Cr and Ge ions

Lead borate glass with compositions 25B2O3–73.8PbO–xGeO2-(1.2 − x) Cr2O3 (x ≤ 1.2 mol. %) is fabricated by the melt quenching procedure. The electrical conductivities (σdc, σac) of fresh samples are measured in the frequency range 100 Hz–1.0 MHz and temperature range 303–393 K. The anomalous behavior observed in the dc activation energy at x = 0.6 mol% is argued to the formation of bridging and non-bridging oxygen bonds. These bonds are formed due to substitution of GeO2 to the expense of Cr2O3 ions in the PbO–B2O3 network. The dependence of ac conductivity on frequency is analyzed through the power law: σacαωs where s ≤ 1.0. The experimental results of s for the considered samples have shown that overlapping large polaron tunneling (OLPT) is the possible conduction model in the considered frequency and temperature ranges. The strength of the OLPT model established on the normal Mayer–Neldel (MN) rule is analyzed and discussed. Furthermore, results of the real and imaginary dielectric constant composed with Cole–Cole diagrams for investigated samples are presented and discussed.

A New Zn(II) Metal Hybrid Material of 5-Nitrobenzimidazolium Organic Cation (C7H6N3O2)2[ZnCl4]: Elaboration, Structure, Hirshfeld Surface, Spectroscopic, Molecular Docking Analysis, Electric and Dielectric Properties.

The slow solvent evaporation approach was used to create a single crystal of (C7H6N3O2)2[ZnCl4] at room temperature. Our compound has been investigated by single-crystal XRD which declares that the complex crystallizes in the monoclinic crystallographic system with the P21/c as a space group. The molecular arrangement of the compound can be described by slightly distorted tetrahedral ZnCl42- anionic entities and 5-nitrobenzimidazolium as cations, linked together by different non-covalent interaction types (H-bonds, Cl…Cl, π…π and C-H…π). Hirshfeld's surface study allows us to identify that the dominant contacts in the crystal building are H…Cl/Cl…H contacts (37.3%). FT-IR method was used to identify the different groups in (C7H6N3O2)2[ZnCl4]. Furthermore, impedance spectroscopy analysis in 393 ≤ T ≤ 438 K shows that the temperature dependence of DC conductivity follows Arrhenius' law. The frequency-temperature dependence of AC conductivity for the studied sample shows one region (Ea = 2.75 eV). In order to determine modes of interactions of compound with double stranded DNA, molecular docking simulations were performed at molecular level.

Experimental Investigation on Structural, Dielectric, and Transport Properties of Copper Doped SrTiO3

Copper -doped Strontium Titanate (STO) with Copper filler percentages of 5% and 10% was prepared through a solid-state reaction method at high temperatures. The structural study of the materials was characterized by the X-ray diffraction technique and confirmed to be in the Cubic phase. Also, the surface morphology of the samples was studied by scanning electron microscopy. The impedance study of the samples was characterized by an LCR meter between the frequencies ranges 102-106 Hz. The exponential dependence of ac conductivity on frequency was confirmed where the value of ac conductivity increases with the rise in filler concentration from 5% to 10%.

Dielectric Behaviour and Electrical Conductivity of α-BiNbO4 and β-BiNbO4 Ceramics

In this work, orthorhombic (α-BiNbO4) and triclinic bismuth niobate (β-BiNbO4) ceramics were prepared by a wet chemical route. The structure of the obtained powders was characterised by X-ray diffraction and the morphology by scanning electron microscopy. The dielectric measurements were performed in the radiofrequency region, at different temperatures, using the impedance spectroscopy technique. The α-BiNbO4 sample presented a temperature-dependent relaxation process, with the corresponding activation energy being calculated through the Arrhenius equation. The AC conductivity dependence on the frequency was in agreement with Jonscher’s universal power. The conduction mechanism in the α-BiNbO4 compound is governed by two processes, which can be ascribed to a hopping transport mechanism. The correlated barrier hopping model until 280 K and the non-overlapping small polaron tunnelling model above 280 K are the most suitable models to describe the conductivity of this sample. In the β-BiNbO4 compound, the motion of mobile charge carriers involves localised hopping between neighbouring sites.

Synthesis and characterization of non-stoichiometric Li1.1Co0.3Fe2.1O4 ferrite nanoparticles for humidity sensors

A humidity sensor plays a crucial role in determining the efficiency of materials and the precision of apparatuses. To measure and control humidity, a non-stoichiometric Li1.1Co0.3Fe2.1O4 mesopore sensor is synthesized by a modified citrate auto combustion technique. The XRD study confirms that prepared nanoparticles are cubic spinel structures having an Fd3m space group. The crystallite size is approximately 36 nm. Thermal analysis measurements show that samples become thermally stable at a temperature of 600 °C. Additionally, the kinetic studies of the prepared samples are calculated via a pseudo-first-order kinetic model. The temperature dependence of AC conductivity is found to increase with increasing temperature. These observations are explained in various models. The resistivity mechanism of humidity sensors is studied via complex impedance spectroscopy (CIS). Its impedance data are fitted to a corresponding circuit, to achieve a simulation of the sample under study. This fitting is detected by the Nyquist plot (Cole–Cole). The obtained data confirm that the studied samples are very sensitive to humidity and can be commercially used as a humidity sensing element.Graphical abstract

Electrical properties of amorphous Ge26InxSe74-x chalcogenide thin films

Amorphous Ge26InxSe74-x (1 ≤ × ≤ 5) chalcogenide thin films have been deposited by thermal evaporation technique. The temperature-dependence of DC conductivity and the temperature and frequency dependence of AC conductivity have been studied in the temperature range 295–523 K and in the frequency range 4–8 MHz. The study of the temperature-dependent of DC conductivity refers to the presence of two distinct conduction mechanisms; the activation energies for each were calculated and it was observed that their values decrease by increasing In content. Besides, in the low-temperature region, the variation of the conductivity against temperature was further analyzed according to the variable-range hopping model based on Mott’s relation, whereby the hopping parameters were evaluated. For all investigated compositions, the variation of the AC conductivity against frequency at the studied temperatures was interpreted according to the correlated barrier hopping (CBH) model which based on Jonscher’s power law, whereby the potential barrier height, WM, and the theoretical optical bandgap, Eg, were calculated.

Structural and electrical characteristics of double perovskite: Sr2FeMoO6

Sr2FeMoO6 ceramic material has been prepared by a mixed oxide reaction route. Analysis of structural, microstructural and electrical characteristics of the material has been analyzed in the limit of frequency (1 kHz–1 MHz) and temperature (25–400 °C). From the preliminary X-ray structural analysis, the structure of the material is found to be tetragonal. The frequency dependence of dielectric constant has been explained by Maxwell-Wagner effect. There is no anomaly observed in the temperature dependent dielectric analysis. The analysis of the Nyquist plot suggests the existence of only grain effect and the sample shows both characteristics of negative and positive temperature coefficient of resistance (NTCR and PTCR). The frequency and temperature dependence of ac conductivity obeys Jonschor’s power law. The analysis of temperature dependence of frequency exponent suggest that the conduction mechanism is follow the overlapping large polaron tunneling (OLPT) and correlated barrier hopping (CBH) conduction phenomena and the activation energy has also been calculated by using Arrhenius equation. The occurrence conduction phenomenon belongs to space charge limited conduction process. The observed low-leakage current density from J-E characteristics curve may be applicable for high temperature applications.

Studies of structural, dielectric and impedance spectroscopy of Sr/ Zr modified BiFeO3 ceramics

Bismuth ferrite (BiFeO3) is the most commonly used multiferroics for multifunctional applications. The polycrystalline samples of co-doped (Sr/Zr) bismuth ferrite (BiFeO3) of a general chemical composition, Bi1-xSrx)(Fe1-xZrx)O3, x = 0.05, 0.1, 0.15, 0.20, were prepared using a standard solid-state reaction method. The basic structural data of the above synthesized electro-ceramics were obtained by X-ray diffraction data and pattern. The surface morphology of the samples was recorded at room temperature by a scanning electron microscope. The scanning electron microscope images show the uniform distribution of grains throughout the surface of the samples. Studies of dielectric and impedance properties of the samples at varying frequency (1 kHz–1000 kHz) and temperature (250C–300 °C) have provided many important information about the materials. The existence of ferroelectricity in the materials was studied by the electric field dependent polarization. The contributions of both grains and grain boundaries towards the total resistance and capacitive behavior of the compounds have been studied by analyzing the frequency and temperature dependence of impedance data.. Study of frequency-temperature dependence of ac-conductivity has provided the information on the type of conduction mechanism. The J–E characteristics of the samples provide the Ohmic behavior with slope closer to 1.

Crystal growth, structural, optical, thermal, dielectric, mechanical and NLO studies of L-tyrosine zinc carbonate single crystals

L-Tyrosine Zinc Carbonate (LTZC) a semi-organic nonlinear optical single crystal has been grown by slow evaporation solution technique. The lattice parameters of the grown crystals are found out by single crystals X- ray diffraction technique. The modes of vibrations of different functional groups present were identified by using Fourier Transform Infrared (FTIR) spectroscopic analysis. The UV–Visible optical absorption spectrum shows that the crystal has high transmission with lowest UV cutoff wavelength of 230 nm. The calculated band gap of LTZC crystal was found to be 5.13 eV. Dielectric constant and dielectric loss for various frequencies and temperatures were performed on LTZC crystal and the results were discussed in detail. The frequency dependence of ac conductivity for different temperatures was studied. The photoconductivity studies confirm that the crystal LTZC has negative photo conducting nature. The mechanical and thermal properties of the grown crystals have been studied. Surface morphological changes are observed in the grown LTZC crystal. The Non-linear optical second harmonic generation conversion efficiency of LTZC was determined using Q-switched Nd: YAG laser. The second harmonic generation conversion efficiency of LTZC is 2.12 times that of KDP.

Structural, AC conductivity, dielectric and catalytic behavior of calcium oxide nanoparticles derived from waste eggshells

Calcium Oxide (CaO) nanoparticles have been synthesized from waste eggshells (ES) as a source of calcium by solution combustion technique using muffle furnace and microwave oven. CaO nanoparticles obtained using muffle furnace (CaO-F) and via microwave oven (CaO-M) were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, AC conductivity and dielectric studies to correlate the physico-chemical behavior. The frequency dependence of AC conductivity, the permittivity (ε′) and dielectric loss tangent (D) studies have been undertaken in the frequency range 50 Hz–5 MHz at room temperature. AC conductivity was found to enhance with an increase in the frequency. The ε′ was found to decrease initially with the frequency and finally reaching a constant value at higher frequencies. The frequency dependence of D was found to exhibit a resonance peak in the studied frequency region. Catalytic activity of CaO-M was correlated with its dielectric behavior.

Consequences of frequency and temperature on the ac-conductivity in ε-GaSe semiconductor single crystal

The frequency and temperature dependence of ac conductivity in a ε-GaSe single crystal was studied by assessing the dielectric constant (εr) and loss tangent (tanδ) over a broad frequency range. GaSe as a dielectric exhibited the typical effect of negative dielectric constant (NDC) at room temperature. A possible mechanism for understanding the reason behind the presence of NDC has been demonstrated on the basis of Drude model. In addition, the crystal as a dielectric material portrayed a remarkable shiftin the εr value from negative to positive at an increase of ~25 oc from room temperature. This clearly demonstrates the phase shift in the circuit behaviour from inductive to capacitive. Overall, the value of εr, tanδ, and σac was found to increase with temperature and frequency. This is primarily a result of the impact of space charge polarization, and frequency power law (σac∝ωn). The presented result thus advocates that the as grown ε-GaSe single crystal could be used as a smart and efficient dielectric material in electronic devices.

Study of dielectric relaxation and polaron conductivity mechanism in sodium nitroprusside (SNP): Na2[Fe(CN)5(NO)]·2H2O

In this study, the crystal structure of sodium nitroprusside, Na 2 [Fe(CN) 5 (NO)]·2H20, has been determined by an analysis by X-ray diffraction (XRD). The crystal is orthorhombic, space group Pnnm. This compound is characterized by different techniques: X-ray diffraction (XRD), differential scanning calorimetry (DSC) and impedance spectroscopy. For electrical properties, impedance spectroscopy was performed at a frequency range of 20 Hz–2 MHz. The dependence of AC conductivity on frequency was found to satisfy Jonscher's universal power law at different temperatures σ ( ω ) = σ D C ( ω , T ) + A ω S ( T , ω ) . This suggested hoping conduction due to three theoretical models. The latter can be attributed to the correlated barrier hopping (CBH) model in region I, overlapping large polaron tunneling (OLPT) in region II and non-overlapping small polaron tunneling (NSPT) mechanism in region III. The temperature dependence and dielectric relaxation of the DC conductivity satisfied the Arrhenius law. The activation energy ranged from 0.033 to 0.164 eV and was similar in the conduction and relaxation mechanisms, indicating that the transport mechanisms were based on hopping phenomena. Moreover, the modulus plots has been characterized by full width at half height or in terms of a non-experiential decay function ϕ(t) = exp(−t/τ)β. The values of the activation energies obtained from the electrical conductivity and electric modulus are near; which suggests that the transport is probably due to the ion hopping mechanisms. Furthermore, this behavior was confirmed by both Nyquist and Argand's plots of dielectric impedance at different measuring temperatures. Crystal structure, Molecular Hirshfeld surfaces, hydrogen bonding, UV absorption and phase transition of the β-NH 3 (CH 2 ) 2 NH 3 SnCl 6 compound. • This compound is crystallized in the orthorhombic system (Pnnm space group). • Differential scanning calorimetric (DSC) experiments show a phase transition at 130 K and 155 K. • The conduction mechanism is attributed to the (CBH) model, (OLPT) and (NSPT) mechanism. • The activation energies suggest that the transport is probably due to the ion hopping mechanisms. • The near value of activation energies obtained from the analysis of M.

Synthesis of novel PANI-based Ti(IV) phosphosulphosalicylate composite cation exchanger — structural, electrical, and impedance properties

In order to combine the properties of inorganic ion exchanger and conducting organic polymer, a new class of organic–inorganic composite cation exchanger PANI–Ti(IV) phosphosulphosalicylate (PTPSS) was synthesized by intercalating polyaniline (PANI) into Ti(IV) phosphosulphosalicylate (Ti(IV) PSS) using sol–gel chemical route with enhanced properties. PTPSS has been characterized by using Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDAX), thermo gravimetric analysis (TGA-DTG), and Transmission Electron Microscopy (TEM). Ac electrical conductivity studies were also performed. This material possessed electrical conductivity of [Formula: see text] – [Formula: see text] [Formula: see text]which falls in the semiconducting range. The frequency (2 × 105– 1 × 106Hz) dependent Ac conductivity at room temperature suggests the evidence for the transport mechanism for the conductivity in PTPSS. The structure of the composite cation exchanger extremely supports its conducting behavior.

Study on nonlinear conduction of PEDOT:PSS conducting polymer

In the present study, solid film of poly (3,4-ethylenedioxythiophene):polystyrenesulfonate, (PEDOT:PSS) has been prepared by casting its aqueous solution at room temperature and are characterized by using X-ray diffraction and differential scanning calorimeter. The temperature-dependent behavior of the ac and dc conductivity of the PEDOT:PSS film has been investigated. The temperature dependence and scan rate dependence of J-V characteristic curves have been tested. The study of frequency dependence of ac conductivity in a wide range of temperature up to 443 K, indicates that the dominant conduction mechanism in PEDOT:PSS film is Overlapping-Large Polaron Tunneling (OLPT). The study of the electrical conduction with applied voltage shows a reversible negative differential resistance (NDR) through the turnover point (T.O.P) for Cu/PEDOT:PSS/Cu device. Threshold current density, Jth, and threshold voltage, Vth at T.O.P as well as NDR are strongly affected by ambient temperature up to 383K and scan rate up to 3V/sec. The turnover behavior has been explained according to a competition between high conduction due to schottky emission and NDR due to field-induced of electrical polarization in conduction paths.

Dielectric investigation of In4Se96-xSx semiconductor: Relaxation and conduction mechanism

Dielectric properties of amorphous semiconductor has been observed in the frequency range of 1 kHz – 1 MHz and a temperature range of 300 K–370 K. Dielectric dispersion is observed in the present samples which is dipolar in nature. The decrease in the dielectric parameter with Sulfur concentration may be due to the decrease in density of defect states. DC conduction loss is smaller than the observed dielectric loss. The analysis of the experimental results indicates that the ac conductivity is temperature, frequency and concentration dependent. Ac conductivity is found to obey the power law ωs, where s ˂ 1. A strong dependence of ac conductivity and exponent s can be well interpreted in terms of correlated barrier hopping (CBH) model. The maximum barrier height Wm were calculated from the results of dielectric loss according to Guintini equation that agree with the theory of hopping of charge carriers over potential barrier as suggested by Elliot in case of chalcogenide semiconductors. The effect of Sulfur was investigated for the obtained results of the studied parameters.

Effects of particle size on the electrical properties of NdFeO3 nanoparticles

In this paper, NdFeO3 nanoparticles were synthesized by the co-precipitation method. The particle size of NdFeO3 nanoparticles was controlled by changing the NaOH concentration in the co-precipitation method, mainly because NaOH concentration could control grain growth. The samples were characterized by X-ray diffraction (XRD) and filed-emission scanning electron microscopy (FE-SEM). They were found that with the change of NaOH concentration, the lattice parameters and cell volume of NdFeO3 nanoparticles changed little, but the average particle size ranged from ~ 100 to ~ 142 nm. And the influence of particle size on electrical properties of samples was also explored. The results showed that the dielectric constant of the sample increased with the decrease of the average particle size, and the dielectric loss decreases. When the average particle size was ~ 100 nm and the frequency was 103 Hz, the dielectric constant (e′) was at most (~ 1.4 × 104) at room temperature, indicating that it had potential applications in dielectric capacitors. In addition, the conduction mechanism of NdFeO3 nanoparticle was studied by frequency dependence of AC conductivity. The effect of the grain and grain boundaries of NdFeO3 nanoparticles on the electrical properties of material was observed in complex impedance spectroscopy. The grain boundary resistance played a leading role in the resistance of the material, and the values of resistance increased with the decrease of the particle size.

Studies of structural and electrical properties of (Pb0.9Bi0.05Dy0.05)(Fe0.1Ti0.9)O3 ceramic

In this communication, detailed studies of structural, dielectric, and electrical characteristics of dysprosium (Dy)-modified bismuth ferrite–lead titanate (BiFeO3–PbTiO3) solid solution, [i.e., (Pb0.9Bi0.05Dy0.05)(Fe0.1Ti0.9)O3)], prepared by a standard high-temperature solid-state reaction route, have been reported. From the preliminary X-ray structural analysis with Rietveld refinement method, the structure of the material is found to be tetragonal. Detailed analysis of surface morphology, X-ray energy-dispersive spectra and elemental mapping has shown uniform distributions of grains of varying size and elemental composition of the compound. The frequency dependence of the dielectric constant has been explained by the Maxwell–Wagner model. As both the components of the solid solution (BiFeO3 and PbTiO3) have high-temperature ferroelectric transition, no dielectric anomaly has been observed in the said experimental range of our temperature dependence of dielectric studies. The detailed analysis of Nyquist plots, using impedance data collected in a wide range of frequency and temperature shows the contributions of both grains and grain boundaries in the resistive and capacitive characteristics of the prepared material. Both negative and positive temperature coefficients of resistance behaviour are observed in the material. The frequency and temperature dependence of ac conductivity obeys Jonscher’s power law and Arrhenius equation. The occurrence of electric field dependence (P–E) hysteresis loop at room temperature shows the ferroelectric property of the material.