Jonscher's Universal Power Law Research Articles

Electrical conduction and optical characteristics of Li2O and Bi2O3 Co-doped zinc-phosphate glassy nanocomposites: A critical observation of mixed ionic electronic effect

In the present report, the combined effects of the co-doping of metal oxide (Bi2O3) and Lithium oxide (Li2O) into the glassy matrix with chemical composition xLi2O-(0.45-x)Bi2O3-(0.15ZnO-0.40P2O5) (x = 0.05, 0.15, 025, and 0.35 mol%) are investigated thoroughly. The FESEM and X-ray diffraction data affirm the crystalline nature of the studied glassy composites. The obtained band gap energy values are declined from (3.68–3.17) eV, while the Urbach energy values are declined from (0.38–0.27) eV. Moreover, the mechanism responsible for AC conductivity has been analyzed using Almond–West formalism and Jonscher's universal power law. The observed rise in both AC and DC conductivity in the glass samples is attributed to the mixed ionic electronic effect. In the ionic diffusion model, an increased defect site concentration improves Li+ ion migration through percolation channels. The reduction in both electrostatic binding energy and strain energy lowers the Anderson-Stuart activation energy, facilitating Li+ ion migration and enhancing conductivity. Additionally, in the small polaron hopping model, an increase in the density of defect states suggests more defect sites that facilitate electronic hopping, creating deep localized states and transitions between localized and extended states. Replacing a Bismuth atom with a Lithium atom increases the number of non-bridging oxygen, enhancing the conduction band tail, reducing the energy needed for hopping conductivity, and increasing conductivity.

Sodium-Poor, Hydroxyl-Rich, Defective Na2Ti3O7 Prepared by γ-Irradiation and Its Enhanced Proton Conductivity.

The use of γ-irradiation to tailor the physicochemical properties of materials is not widely applied to layered alkali metal oxides. Herein, we show that γ-irradiation (up to 400 kGy) of Na2Ti3O7 leads to a sodium-poor, hydroxyl-rich analogue where the layered structure, plate-like morphology, and textural properties are preserved. The deintercalation of sodium ions modifies the Ti-O bond lengths and expands the unit cell; the latter is supported by density functional theory (DFT) calculations. 23Na solid-state NMR suggests the transport of the symmetric, 7-fold Na2 sites to an intermediate environment, which is closer to the asymmetric, 9-fold Na1 sites. An 8 wt % mass loss (1.4 mol water/mol titanate) is observed, indicating an increased concentration of protons/hydroxyls. These hydroxyl groups (i.e., lattice protons) possess higher thermal stability than solely surface-adsorbed ones in the nonirradiated sample. At 200-400 kGy, the proton conduction (50 °C and ∼70% RH) of ∼10-6 S·cm-1 is 1 order of magnitude larger than that in the nonirradiated sample; the relaxation time decreases from 30 to 2-6 μs with γ-irradiation. The γ-dose dependence of dielectric loss is also present and analyzed using the Jonscher universal power law, indicating the low-frequency dispersion behavior characteristics of high charge densities.

Dielectric relaxation and electrical conductivity in lead-free organic ferroelectric diisopropylammonium bromide (dipaBr)

In this communication, we explore the dielectric relaxation behavior of the novel organic salt Diisopropylammonium Bromide (dipaBr), focusing on the universal relaxation law. We conduct dielectric relaxation and conductivity analyses across a broad spectrum of temperatures (325K–443K) and frequencies (20 Hz–20 MHz). The irregularity in peak broadening observed in complex modulus spectroscopy indicates a distribution of relaxation periods with varying time constants, confirming that the relaxation is of the non-Debye type. To interpret the experimental findings, we utilize the Havriliak-Negami (HN) formula in our investigation of dielectric relaxation. The parameters derived from the model are discussed. The relaxation process in the material appears to depend on temperature. The ac conductivity profile follows Jonscher's universal power law, and the relationship between bulk DC conductivity and temperature follows an Arrhenius-like pattern.

Rietveld refinement, core level electron shell structure and frequency-dependent dielectric behavior of vanadium bismuth oxide microstructures

Solid-state reaction method was employed to synthesize a series of complex compound system V2-xBi2xO5-δ (0.01 ≤ x ≤ 0.04), and their electrical properties at room temperature were examined through impedance spectroscopy within the frequency range of 40 Hz to 10 MHz. The X-ray diffraction (XRD) is refined to obtain the complete crystallographic profile of the compounds. The frequency-dependent conductivity exhibited adherence to Jonscher's universal power law across all compositions. As the bismuth concentration increased from x = 0.01 to 0.04, both AC and DC conductivity showed a systematic increase. AC conductivity raised from 3.17 × 10−4Sm−1 to 4.3 × 10−4 Sm−1 at 10 MHz, while DC conductivity increased between 1.56 × 10−4Sm−1 and 2.28 × 10−4Sm−1. The dielectric constant (εr') decreased with increasing frequency, stabilizing around 100 kHz. The electric modulus peaks at higher frequencies, reflecting relaxation processes, and approaches zero at lower frequencies due to the absence of electric polarization.

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.

Effect of Fe3+ ions substitution on electrical and dielectric properties of MgFexCr2-xO4 (x = 0, 0.2, and 0.4 mol%) chromites prepared by solution combustion method

This paper reports the structural, dielectric and electrical properties of Fe3+ ions substituted magnesium chromite with composition MgFexCr2-xO4 (x = 0, 0.2, and 0.4 mol%) synthesized via solution combustion method. The structural analysis was done by XRD pattern which confirmed the formation of cubic crystal symmetry of the samples with Fd-3 m space group. The value of lattice parameters of MgFexCr2-xO4 chromites slightly increased with increasing concentration of Fe3+ ions. The TEM (Transmission electron microscopy) micrographs at different magnifications showed the spherical particles of the sample and average particle size was found to be ≈ 56.22 nm. The dielectric parameters (dielectric constant and dielectric loss) and ac conductivity were investigated in the frequency range of 100 Hz–100 kHz and temperature range of 50 °C–350 °C. The dielectric studies showed that the dielectric parameter decreases in high frequency range which can be explained by Maxwell-Wagner type of space charge polarization. The dielectric constant increases with increasing concentration of Fe3+ ions due to increase in polarization. The frequency and temperature dependent ac conductivity was studied and found that the conductivity value increases with an increase in frequency and temperature, which followed the Jonscher's universal power law. The ac conductivity decreases with increasing Fe3+ ions due to formation of grain boundary defect barrier. The non-Debye type relaxation behavior of the MgFexCr2-xO4 samples was confirmed by the Cole-Cole plot. The obtained result shows the capability of magnesium chromite for fabrication of micro-electronic devices, sensors, and other electronic devices.

Photocatalytic degradation of Rhodamine B dye via Bi2O3 embedded BaO-P2O5-TeO2 glass nanocomposites: An ab initio study of structural, optical, and electrical transport properties

Bismuth incorporated glassy systems with composition xBi2O3-(1-x) [0.3BaO-0.3P2O5-0.4TeO2] (where x = 0.10, 0.15, 0.20, and 0.25) are synthesized by melt quenching technique. The glassy systems are examined for their structural, and surface morphological properties using XRD, SEM, and EDX analysis. A study of photocatalytic activity for the degradation of common organic dyes like Rhodamine B (RhB) dye under visible light is also carried out. From UV-vis absorbance data, the calculated optical band gap energy values declined from (2.99-2.56) eV, whereas the Urbach energy and refractive index values increased from (0.35 -0.52) eV, and (2.39 - 2.52), respectively with the rise of Bi2O3 content(x). Additionally, the fundamental processes of electrical conductivity have been studied within the framework of Jonscher's universal power law and the Almond-West formalism. The Mott and Greaves model asserts that the small polaron hopping model underlies DC conductivity; as Bi2O3 content increases, DC conductivity rises, but hopping distance (Rhop) and hopping energy (Whop) drop dramatically. The electrical conductivity study reveals the semi-conducting nature of the as-prepared samples. In our present study, we are focusing on the structural, optical, and electrical transportation properties, additionally, we investigated this class of glassy materials as a promising candidate for photocatalytic dye degradation. Our study reveals that RhB dye can degrade up to 75% within 340 min of visible light illumination. Moreover, the test demonstrates the production of superoxide radicals by the CB-electrons and hydroxyl radicals by the VB holes enables efficient photocatalytic dye degradation.

Electrical properties and conduction mechanisms of Ba0.75Sr0.25Ti1-xZrxO3 ceramics synthesized by sol-gel route

A series of Ba0.75Sr0.25Ti1-xZrxO3 (x = 0, 0.01, 0.03, 0.05, and 0.1) ceramics were synthesized via a facile sol-gel route. The confirmation of a tetragonal structure was achieved through Rietveld refinement of the powder X-ray diffraction (XRD), and the finding was subsequently corroborated by Raman spectroscopy. The Scanning electron microscopy (SEM) confirmed the roughly cubical-shaped grains and average grain size is 0.31 μm for x = 0 and 0.70 μm for x = 0.05. The electrical properties such as dielectric constant, dielectric loss and ac/dc conductivity were investigated as a function of temperature and frequency. The Jonscher's universal power law (JPL) and Arrhenius equation have been used for the analysis of conductivity. The electrical conductivity variation at intermediate frequencies was explained using JPL. The Super-linear power law (SPL) explains the electrical response at higher frequencies. The temperature-dependent frequency exponents ‘s1’ and ‘s2’ were employed to predict the quantum mechanical tunneling (QMT), non-overlapping small polarons hopping (NSPT), and correlated barrier hopping (CBH) conduction mechanisms.

Electrical Transport Properties and Hopping Mechanism of ZrCuSiAs Type Compound GdFeAsO

Abstract Iron-based ceramic GdFeAsO has been prepared using the solid-state reaction method. This material exhibits unique properties, showing superconductivity at extremely low temperatures and behaving as a semiconductor at high temperatures. Raman spectroscopy revealed various Raman active modes in the sample. UV-visible spectroscopy was employed to study the optical properties of the material in the wavelength range of 200-800 nm. Using Tauc's plot, the optical band energy values of the sample were estimated to be approximately 2.78 eV. The electrical characterizations have been performed through an impedance analyzer. Additionally, the sample displayed negative temperature coefficient of resistance behavior and positive temperature coefficient resistance. The thermistor parameters are evaluated using the bulk resistance at various temperatures. This opens up potential uses for thermistors in devices like fuses and temperature sensors. The ac conductivity spectrum of the sample followed both Jonscher's universal power law and the Arrhenius equation. The activation energy was calculated for different temperature regions. The correlated barrier hopping model is used to analyze the electrical conduction mechanism in the sample. This study provides insights into the unique electrical and optical properties of the GdFeAsO ceramic and sheds light on its potential applications in various fields.

Effect of Zn doping on optical properties and electrical conductivity-mechanism of Sb-Ge-Se chalcogenide glassy systems

The present communication inspects the impact of zinc doping on the s optical, and electrical characteristics of bulk glassy samples made up of xZn-(0.1-x)Sb-0.2Ge-0.7Se (x = 0.01, 0.02, 0.03, 0.05). The X-ray diffraction patterns confirm that the samples are amorphous. In addition to various optical constants, the linear refractive index, and skin depth have been determined. The decreases in band gap energy values from 1.62 eV to 1.56 eV may be attributed to the rise in Unbach energy values from 0.15 eV to 0.32 eV. The obtained value of refractive indices also increases from 2.91 to 2.95 with the rising Zn content. By using the paradigm of Jonscher's universal power law and the Almond-West formalism, the underlying mechanisms of AC conductivity have been investigated. The AC conductivity increases with temperature and displays semiconducting characteristics. As the power-law exponent (s) reduces with increasing temperature, the correlated barrier hopping model is used to explain the AC conduction mechanism. DC conduction mechanism is described by Mott's and Greaves's variable range hopping model. The anticipated values of tiny polaron hopping energy (Whop) and hopping distance (Rhop) shed light on the increasing trend of DC conductivity with increased Zn concentration.

Studies on fluoride ion conductivity of the mechanochemically synthesized β-KSbF4 for all-solid-state fluoride-ion batteries

All-solid fluoride ion batteries (FIBs) are considered as the potential alternative to lithium-ion batteries due to their ultra-high volume energy density and high safety. Nevertheless, the major challenge for high-performance FIBs lies in the difficulty of finding a suitable solid-state electrolyte with both high ionic conductivity and easy fabrication. Herein, the air-stable β-KSbF4 with a high F− ion conductivity of 2.06×10−4 S cm−1 at 60 °C is firstly synthesized by mechanochemical synthesis combined with low-temperature annealing treatment, and the underlying mechanisms of fast ion conduction in β-KSbF4 is investigated as well. The analysis of the conductivity spectra based on Jonscher's universal power law shows that the hopping frequency changes by orders of magnitude from 30 °C (1.69×105 Hz) to 80 °C (1.67×106 Hz), and the carrier concentration is almost independent of the temperature change. The difference between the two different parameters means that the hopping process of F− ions rather than the concentration of the charge carriers determines the conductivity of β-KSbF4. Integrating β-KSbF4 with Ag cathode and Pb + PbF2 anode, a reversible cycling of conversion-type all-solid-state FIBs with a first discharge capacity of 77.4 mAh g−1 at 60 °C is achieved and can work stably for 50 cycles without considerable capacity fade. Hence, it is believed that the study on the ionic conduction characteristic of β-KSbF4 synthesized by the mechanochemical synthesis method and its successful application in all-solid-state FIBs can open a new horizon toward the development of all-solid-state FIBs.

Exploring the comparison of optical, dielectric and photocatalytic performance of Yb3+ and Gd3+ half-doped DyCrO3 nanostructures

The auto combustion sol-gel method was utilized to prepare Dy0.5Gd0.5CrO3 (DGCO) and Dy0.5Yb0.5CrO3 (DYCO) nanomaterials. The single-phase formation of materials was confirmed with the X-ray diffraction technique. Utilizing Kubelka-Munk function, the optical bandgap energy values were found to be 3.39 eV (DGCO) and 2.61 eV (DYCO). The dielectric properties were analyzed in frequency range from 10 kHz to 2 MHz and a temperature range from 25 °C to 225 °C. The conduction mechanism followed the universal Jonscher's power law, which revealed that conduction process was primarily governed by the small polaron hopping. The CBH, NSPT, and QMT models were applicable for the a.c. conduction in the DGCO nanomaterial whereas the CBH and NSPT models were more appropriate for the DYCO nanomaterial. The Kohlrausch, Williams and Watts function was used to correlate the imaginary electrical modulus spectrum, which confirmed that the relaxation process in the materials was non Debye-type. An impedance spectroscopic measurement revealed the influence of grain and grain boundaries and it followed negative temperature coefficient resistance behaviour at higher temperatures. Both DGCO and DYCO nanomaterials were also investigated for their photocatalytic degradation of Rhodamine B (RhB) and Methylene Blue (MB) dyes. The degradation, under direct solar irradiation, was 84 % (RhB) and 63 % (MB) for DYCO nanomaterial and 54 % (RhB) and 44 % (MB) for DGCO nanomaterial, indicating their potential in water treatment.

Effect of the inclusion of Fe2O3 on the optical and electrical transport properties into sodium-zinc-phosphate quaternary glassy systems

Glass systems, xFe2O3–(35-x)Na2O–25ZnO–40P2O5) (x = 10, 15, 20, and 25 mol%), were prepared using the melt-quenching technique. FTIR analysis revealed stretching vibrations of the P–O–P and P–O bonds and XRD investigation revealed a pure amorphous structure. It was discovered that with rising Fe2O3 content (x), the values of density increased, but the values of molar volume decreased. The Fe2O3 incorporation into the glass matrix resulted in decrement in the optical band gap energy (Eopt) value from 2.99 to 2.16 eV. The addition of Fe2O3 to the glass network reduced the quantity of non-bridging oxygen ions, improving the observed refractive index value. According to the Mott and Greaves model, the small polaron hopping model was responsible for the DC conductivity mechanism, and the density of states at the Fermi level increased as DC conductivity increased with increasing Fe2O3 content, but hopping distance (Rhop) and hopping energy (Whop) sharply decreased. It was concluded that the AC conductivity mechanism followed the correlated barrier hopping model as the power-law exponent (s) of Jonscher's universal power law decreased with temperature. AC conductivity increased with rising Fe2O3 concentration due to a decrement in the polaron hopping distance value and an increment in the concentration of defect pair states.

Nd substitution response on structural, dielectric, and electrical features of bismuth iron titanate

Nowadays, there have been much consideration to develop eco-friendly advanced materials, which have many applications in the field of multiferroics, sensors, actuators, magnetically modulated transducer devices, etc. Hence, the preparation of lead-free based multifunctional materials has now become of great interest to researchers. The present study reports the synthesis and study of structural, dielectric, and multiferroics characteristics of (Bi0.8Nd0.2)(Fe0.5Ti0.5)O3 material. The compound was synthesized using a conventional solid-state reaction method (calcination at 950 °C). The X-ray diffraction analysis of the compound confirms the single-phase formation with orthorhombic symmetry. The surface morphology of the material has been examined by the field emission scanning electron microscopy (FESEM) method, which shows uniform grain distribution in the microstructural image. Grains were to be found of different sizes with few voids. Energy dispersive X-ray (EDX) shows the purity of the sample with an equivalent amount of weight and atomic percentage. Dielectric and impedance analysis have been investigated in a wide range of frequencies and temperatures. Frequency-dependent ac-conductivity obeys Jonscher's universal power law. The P-E loop tracer was used to study the ferroelectric nature of the sample. Magnetic field-dependent magnetization is measured at room temperature by a vibrating sample magnetometer (VSM). The current study provides efficient, eco-friendly, and interesting results for further application purposes.

Study on the effect of bismuth oxide on the structural, optical and dielectric properties of strontium phosphate glasses

ABSTRACT The melt-quenching technique was used to prepare strontium phosphate glasses with bismuth oxide. The impact of replacing Bi3+ with Sr2+ on density (d), molar volume (Vm), and glass transition temperature (Tg) was investigated. The FTIR spectra revealed that the structural units of the samples consisted of [BiO3], [BiO6], [PO3], and [PO4]. UV-visible spectroscopy was used to study the optical transmittance, energy band gap (Eopt), and Urbach energy (Etail). The Wemple-Didomenico model successfully described the dispersive behavior of the refractive index. Impedance spectroscopy is utilized to determine the electrical and dielectric properties. The AC conductivity followed Jonscher's universal power law, and it was observed that as the concentration of Bi2O3 increased, the frequency exponent (s) decreased. The dielectric constant (ϵ’) and dielectric loss (tan δ) were found to be frequency and composition dependent. The parameters describing the dispersion of dielectric constant are obtained through the Cole-Davidson relation.

A brownmillerite electronic material LiBiFe2O5: structural, dielectric, electrical, and ferroelectric properties for device application

ABSTRACT A lead-free brownmillerite ferroelectric material LiBiFe2O5 (LBFO) has been synthesized via a solid-state reaction technique. Using the procedure of N-TREOR method of X-ray diffraction, the crystal structure of the prepared sample is found to be monoclinic with lattice parameters: a = 13.6726 Å, b = 4.1560 Å, c = 8.5317 Å, and β = 102.89˚. Based on analysis of electrical data, the existence of Koop's and Maxwell–Wagner relaxation phenomena and dielectric relaxation in the material has been confirmed. This analysis has also shown a high impact of the dielectric permittivity (ϵr) and low tangent loss (tanδ) on using the material in some electronic devices. A detailed study of the frequency-temperature-dependent ac conductivity has suggested the presence of Jonscher's universal power law in the material. As the material has thermistor constant (β) values of 4019.26, 11535.75, and 484.36 in different temperature ranges indicating high-temperature NTC thermistor application.

Investigating the temperature and frequency dependence of dielectric response using AC impedance spectroscopy on SnO2

In this investigation, we explored tin oxide's dielectric properties and impedance spectroscopy, focusing on its temperature dependence across a frequency range of 20 Hz to 2 MHz. We analyzed the x-ray diffraction pattern using Rietveld refinement and established that the sample has a tetragonal phase with P42/mnm space group. Afterward, the surface structure of the SnO2 was examined using (FESEM) and Raman spectroscopy. Through FESEM, we analyzed the morphology of the prepared sample, which were nanospheres in structure. In contrast, we discovered the non-degenerated A1g and B2g modes through Raman spectroscopy, which matches well with the literature and displays the contraction and expansion of Sn-O bonds. We performed dielectric studies at varying frequencies and temperatures to further analyze the properties. We discovered that the ac conductivity increased as temperature and frequency increased. The activation energy was calculated using dc electrical conductivity measurement. The DC conductivity exhibits a temperature dependence that can be described by the Arrhenius equation, which reveals that the tin oxide has to conduct behavior with an estimated activation energy of 0.025 eV, 0.035 eV, and 0.082 eV for three temperature ranges of 80–120 K, 120–175 K, and 175–270 K, respectively. Additionally, the AC conductivity data conforms to Jonscher's universal power law. The frequency-dependent parameter “s” increases as the temperature elevates. A transition from the QMT (Quantum mechanical tunneling) model to NSPT (non-overlapping small polaron tunneling) was employed to analyze the data.

Effect of heavy metal and alkaline earth oxides on the optical and electrical mechanism of vanadium-phosphate amorphous glassy systems

In the current work, the collective effects of the doping of heavy metal oxide (Bi2O3) and alkaline metal oxide (BaO) into the host glassy network having chemical formula xBi2O3-(0.4-x)BaO-0.3V2O5–0.3P2O5 (x = 0.05, 0.15, 025, and 0.35) are studied systematically. The X-ray diffraction reveals the amorphous nature of the composites under study. Physical properties like density and molar volume have been investigated and correlated with structural modifications. The findings of Tauc's plot have confirmed the increment in optical band gap energies from 2.81 eV to 3.51 eV and correlated with the decrement of Urbach energy values. Some spectroscopic parameters like refractive index, reflectivity, reflection factor, and non-linear refractive index have been examined and interpreted accordingly. The mechanism is accountable for AC conductivity has been inspected using Almond–West formalism and Jonscher's universal power law, revealing semiconducting features. The small polaron hopping route with various activation energies at numerous temperature ranges causes non-linearity in DC conductivity in all of the studied samples.

Characterization of BiFeO3–Al2O3 nano-composites: A study of structural, microstructural, electrical, and magnetic properties

Results: of the studies on the structural, magnetic, and electrical properties of BiFeO3–Al2O3 nanocomposites prepared using the sol-gel method have been reported. The X-ray diffraction results confirm bi-phase structure of the composites with the presence of some impurity phases of Bi25FeO40 and Bi24A12O39. Field emission scanning electron microscopy images revealed the crystalline nature composed of grain and grain boundaries of both the pure and composite samples. Energy-dispersive X-ray spectroscopy confirms the absence of unwanted components. Magnetic characterization reveals weak ferromagnetic behaviour of BiFeO3 and composites while diamagnetic behaviour of Al2O3. The maximum saturation magnetization in the pure BFO sample is ∼ 6 emu/gm, but this magnetization is lowered by up to 63% and is determined to be ∼ 3.8 emu/gm with the 30% addition of Al2O3 in the BFO matrix. Electrical measurements demonstrate that the addition of Al2O3 nanoparticles leads to a reduction in the dielectric constant, loss tangent, and ac conductivity. A.C. conductivity was found to follow Jonscher's universal power law and to be dominated by the correlated barrier hopping mechanism in the conduction process, according to frequency-dependent ac conductivity analysis. Additionally, impedance analysis reveals a field-induced excitation of charge carriers, resulting in a noteworthy reduction in sample impedance. Overall electrical properties have been discussed in the context of oxygen vacancies, secondary phases, defects, and disorder in details

Studies of structural, dielectric, and electrical properties of polycrystalline barium bismuth tungstate for thermistor application

In this communication, preliminary investigation of structural and detailed analysis of electrical proprties of a new barium bismuth tungstate of a chemical composition Ba3Bi2WO9, produced via a standard high-temperature solid-state reaction method, is presented. The basic crystal structure of the compound is monoclinic (a = 8.4621 Å, b = 6.7358 Å, c = 6.9064 Å and β = 109.94°). The homogeneous distribution of grains (average grain size = 1.717 μm) is studied via surface morphology demonstrating the feasibility of fabricating a high-density sample under experimental conditions. This compound shows ferroelectric and related properties, which have been experimentally verified by examination of the frequency-temperature dependence of capacitance, impedance, and other related behaviors. The variation of ac conductivity of the material under alternating current varies according to Jonscher's universal power law. The ferroelectric property of the material (Pr = 0.331C/cm2, Ec = 0.207 kV/cm) is demonstrated by the electric field-dependent polarisation (P-E loop) study. The temperature dependence of resistance yields a thermistor constant (β) and temperature coefficient of resistance (TCR), which may be useful for fabricating thermistor-based device applications.