Thermodynamic properties and application of CBH model in the ac conductivity of LiNi1.5P2O7 ceramic

The glass composition 40 Li 2 O –5 WO 3–(55−x) B 2 O 3: x V 2 O 5 for x = 0.2, 0.4, 0.6 and 0.8 is chosen for the present study. The glass samples were synthesized by conventional melt-quenching technique. The dielectric properties such as constant (ε′), loss (tan δ) and ac conductivity (σac) are carried out as a function of temperature (30–270°C) and frequency (102–105 Hz). The glass sample (at x = 0.6) exhibited highest ac conductivity (σac) and spreading factor (β) among all the samples. All glasses exhibited mixed conduction (both electronic and ionic) at high temperatures. The frequency exponent s denotes the ac conduction mechanism is associated with both QMT model (at low temperatures) and CBH model (at high temperatures).

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Electric and dielectric properties of CdSO4-doped borate glasses

International Journal of Modern Physics B ◽

10.1142/s0217979219500115 ◽

2019 ◽

Vol 33 (04) ◽

pp. 1950011 ◽

Cited By ~ 3

Author(s):

E. M. Ahmed

Keyword(s):

Ac Conductivity ◽

Thermal Activation ◽

Relaxation Times ◽

Wide Distribution ◽

Ion Density ◽

Cbh Model ◽

Oxygen Ion ◽

Dielectric Data ◽

Quenching Method ◽

Loss Formula

A system of (100-x)B2O3⋅xCdSO4glasses (0 [Formula: see text]x [Formula: see text] 40) is set by the ordinary quenching method. Density ([Formula: see text]), molar volume (V[Formula: see text]) and oxygen ion density (N[Formula: see text]) are found to increase with the increase of CdSO4in the samples. The dc conductivity ([Formula: see text]) and the ac conductivity ([Formula: see text]) are measured in the temperature range from 308 to 735 K. [Formula: see text] is found to follow the thermal activation Arrhenius relation with activation energies between 0.36 and 0.76 eV. Ac conductivity and the exponent factor (s) confirm that the CBH model is the origin of the conduction. The dielectric constant ([Formula: see text]) and loss ([Formula: see text]) are studied as a function of the temperature and frequency. The dielectric data are fitted according to the Cole–Cole equations. The values of [Formula: see text] parameter are found to vary between 0.2 and 0.58 which means that these glasses exhibit a wide distribution of relaxation times.

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AC conductivity and dielectric relaxation of Se80−xTe20Bix (x=6, 12) glasses

Physics and Chemistry of Glasses European Journal of Glass Science and Technology Part B ◽

10.13036/17533562.60.6.014 ◽

2019 ◽

Vol 60 (6) ◽

pp. 222-230

Author(s):

Deepika Deepika ◽

Hukum Singh

Keyword(s):

Dielectric Relaxation ◽

Ac Conductivity ◽

Lower Energy ◽

Dielectric Relaxation Time ◽

Frequency Exponent ◽

Dielectric Parameters ◽

Cbh Model ◽

Increase With Increase ◽

Different Temperatures ◽

Frequency Temperature

The present paper reports the ac conductivity and dielectric relaxation of Se80−xTe20Bix (x=6, 12) glasses at various temperatures and frequencies. It was found that ac conductivity increases on increase of frequency, temperature as well as Bi content. The increase in conductivity is due to the formation of lower energy Se–Bi and Te–Bi bonds which takes the system to a stable lower energy configuration. The values of frequency exponent (s) were calculated and it was found that samples obey CBH model of conduction. Density of states (N(Ef)) near the fermi level were calculated at different temperatures and it was found that addition of Bi increases the number of localised states in the tails which leads to increase in ac conductivity. Further, it was found that dielectric parameters increase with increase in temperature. However, a decrease in both dielectric constant (ε′) and dielectric loss ((ε″) was observed with increase in frequency. Beside this, dielectric relaxation time (τ) and activation energy of relaxation (∆Eτ) were also determined for both the samples under study and was found to be lower for Se68Te20Bi12 glass.

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TRANSPORT PROPERTIES OF THERMALLY EVAPORATED In2Se3 THIN FILMS

Surface Review and Letters ◽

10.1142/s0218625x09013293 ◽

2009 ◽

Vol 16 (05) ◽

pp. 723-729 ◽

Cited By ~ 6

Author(s):

D. NITHYAPRAKASH ◽

B. PUNITHAVENI ◽

J. CHANDRASEKARAN

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Ac Conductivity ◽

Thermal Evaporation ◽

Frequency Range ◽

X Ray Diffraction ◽

Cbh Model ◽

X Ray ◽

Correlated Barrier Hopping ◽

Tan Δ

Thin films of In2Se3 were prepared by thermal evaporation. X-ray diffraction indicated that the as-grown films were amorphous in nature and became polycrystalline γ-In2Se3 films after annealing. The ac conductivity and dielectric properties of In2Se3 films have been investigated in the frequency range 100 Hz–100 kHz. The ac conductivity σ ac is found to be proportional to ωn where n < 1. The temperature dependence of both ac conductivity and the parameter n is reasonably well interpreted by the correlated barrier hopping (CBH) model. The values of dielectric constant ε and loss tangent tan δ were found to increase with frequency and temperature. The ac conductivity of the films was found to be hopping mechanism. In I–V characteristic for different field and temperature were studied and it has been found that the conduction process is Poole–Frenkel type.

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Loss Peaks in the AC Conductivity of a-Si:H

MRS Proceedings ◽

10.1557/proc-258-801 ◽

1992 ◽

Vol 258 ◽

Author(s):

L. Schirone ◽

Ya. Yu. Guseinov ◽

G. De Cesare ◽

A. Ferrari ◽

F.P. Califano

Keyword(s):

Electrical Conductivity ◽

Linear Dependence ◽

Ac Conductivity ◽

Electronic States ◽

Temperature Dependent ◽

Cbh Model ◽

Correlated Barrier Hopping ◽

Simple Pair ◽

Staebler Wronski Effect ◽

Pair Hopping

ABSTRACTThe electrical conductivity of a-Si:H films was investigated in the temperature range 300K - 450K under an alternative electric field whose frequency was in the range 100 Hz - 6×106 Hz. Loss peaks were detected, located at a temperature dependent frequency and superimposed to a nearly linear dependence on frequency. Their amplitude has found to be sensitive to Staebler-Wronski Effect. The observed photodegradation-sensitive loss peaks have been described in terms of a Simple Pair Hopping (SPH) mechanism, involving the electronic states associated to dangling bonds, superimposed to a broadband process described by Correlated Barrier Hopping (CBH) model.

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Conduction Mechanism by Using CBH Model in Fe3+ and Mn3+ Ion Modified Pb(Zr0.65−xAxTi0.35)O3 (A = Mn3+/Fe3+) Ceramics

Journal of Materials ◽

10.1155/2013/802123 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10

Author(s):

Niranjan Sahu ◽

S. Panigrahi ◽

Manoranjan Kar

Keyword(s):

Ac Conductivity ◽

Conduction Mechanism ◽

Rietveld Method ◽

Compositional Analysis ◽

Energy Dispersive Spectrum ◽

Ion Concentration ◽

Present Sample ◽

Cbh Model ◽

Dielectric Constant And Loss ◽

Xrd Patterns

Polycrystalline samples of manganese and iron substituted lead zirconium titanate (PZT) with general formula Pb(Zr0.65−xAxTi0.35)O3 (A = Mn3+ and Fe3+) ceramics have been synthesized by high temperature solid state reaction technique. X-ray diffraction (XRD) patterns were recorded at room temperature to study the crystal structure. All the patterns could be refined by employing the Rietveld method to R3c space group with rhombohedral symmetry. Microstructural properties of the materials were analyzed by scanning electron microscope (SEM), and compositional analysis was carried out by energy dispersive spectrum (EDS) measurements. All the materials exhibit ferroelectric to paraelectric transition. The variation of dielectric constant and loss tangent with temperature and frequency is investigated. The decrease of activation energy and increases of AC conductivity with the Fe3+ or Mn3+ ion concentration have been observed. The AC conductivity has been analyzed by the power law. The frequency exponent with the function of temperature has been analyzed by assuming that the AC conduction mechanism is the correlated barrier hopping (CBH) model. The conduction in the present sample is found to be of bipolaron type for Mn3+ ion-doped sample. However, the conduction mechanism could not be explained by CBH model for Fe3+ ion-doped sample.

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Influence of BaO Doping on the Structural, ac Conductivity, and Dielectric Properties of BiFeO3 Multiferroic Nanoparticles

10.21203/rs.3.rs-204688/v1 ◽

2021 ◽

Author(s):

M. S. Ayoub ◽

Ibrahim Morad ◽

H. Elhosiny Ali ◽

M. M. Mostafa ◽

M. M. El–Desoky

Keyword(s):

Curie Temperature ◽

Ac Conductivity ◽

Conduction Mechanism ◽

Fourier Transforms ◽

Information Storage ◽

X Ray Diffraction ◽

Cbh Model ◽

Storage Devices ◽

Electrical Conductivities ◽

Xrd Patterns

Abstract The Bi1 − xBaxFeO3 (BiBaFeO3) multiferroic nanoparticles with different Ba molar concentrations were fabricated in reliance on the solid-state reaction technique. Nanostructures of the prepared samples were confirmed by X-ray diffraction (XRD) together with Fourier transforms infrared (FTIR) spectroscopy, whereas the ac conductivity, dielectric and ferroelectric features were examined depending on the RLC Bridge, and Sawyer–Tower circuit. XRD patterns displayed the creation of rhombohedral–hexagonal single-phase of BiBaFeO3. The formation of BiBaFeO3 multiferroic nanoparticles was confirmed by FTIR spectra. Curie temperature (TC) was observed around 1121–1189 K. Ferroelectric polarization was enhanced with remnant polarization of 88.8 µC/cm2 by Ba2+ ions substitution at x = 0.15 mol%. Besides, ac electrical conductivities as a function of frequency as well as temperature were reported for all BiBaFeO3 multiferroic nanoparticles, which exhibit a strong frequency dependence with conduction mechanism is the correlated barrier hopping (CBH) model. The obtained high polarization and Curie temperature enhance their use in information storage devices.

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Models of Thermodynamic Properties of Prominences

International Astronomical Union Colloquium ◽

10.1017/s0252921100065799 ◽

1979 ◽

Vol 44 ◽

pp. 349-355

Author(s):

R.W. Milkey

Keyword(s):

Thermodynamic Properties ◽

Mass Transport ◽

Emission Spectrum ◽

Thermodynamic Parameters ◽

Working Group ◽

Physical Processes ◽

Theoretical Concepts ◽

Group 3 ◽

Observational Techniques

The focus of discussion in Working Group 3 was on the Thermodynamic Properties as determined spectroscopically, including the observational techniques and the theoretical modeling of physical processes responsible for the emission spectrum. Recent advances in observational techniques and theoretical concepts make this discussion particularly timely. It is wise to remember that the determination of thermodynamic parameters is not an end in itself and that these are interesting chiefly for what they can tell us about the energetics and mass transport in prominences.

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