Studies of dielectric relaxation and thermally activated a.c. conduction in Se78 − xTe20Sn2Cdx (0 ≤ x ≤ 6) chalcogenide glass

2016 ◽  
Vol 28 (7) ◽  
pp. 5634-5644 ◽  
Author(s):  
Amit Kumar ◽  
Neeraj Mehta
Keyword(s):  
Dielectric Relaxation ◽  
Chalcogenide Glass ◽  
Thermally Activated

scholarly journals Study of dielectric relaxation and thermally activated a.c. conduction in lead containing topological glassy semiconductors

RSC Advances ◽  
2017 ◽  
Vol 7 (31) ◽  
pp. 19085-19097 ◽  
Author(s):  
Arvind Sharma ◽  
N. Mehta
Keyword(s):  
Dielectric Relaxation ◽  
Cbh Model ◽  
Thermally Activated

Illustration of CBH model of the Coulombic well.

scholarly journals High-Temperature Dielectric Relaxation Behaviors in Mn3O4 Polycrystals

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4026 ◽  
Author(s):  
Songwei Wang ◽  
Xin Zhang ◽  
Rong Yao ◽  
Liguo Fan ◽  
Huaiying Zhou
Keyword(s):  
High Temperature ◽  
Dielectric Relaxation ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Thermally Activated ◽  
Dielectric Relaxations ◽  
Plasma Sintering ◽  
Ptcr Effect ◽  
Temperature Relaxation ◽  
Lower Temperature

High temperature dielectric relaxation behaviors of single phase Mn3O4 polycrystalline ceramics prepared by spark plasma sintering technology have been studied. Two dielectric relaxations were observed in the temperature range of 200 K–330 K and in the frequency range of 20 Hz–10 MHz. The lower temperature relaxation is a type of thermally activated relaxation process, which mainly results from the hopping of oxygen vacancies based on the activation energy analysis. There is another abnormal dielectric phenomenon that is different from the conventional thermally activated behavior and is related to a positive temperature coefficient of resistance (PTCR) effect in the temperature region. In line with the impedance analyses, we distinguished the contributions of grains and grain boundaries. A comparison of the frequency-dependent spectra of the imaginary impedance with imaginary electric modulus suggests that both the long range conduction and the localized conduction are responsible for the dielectric relaxations in the Mn3O4 polycrystalline samples.

scholarly journals Dielectric relaxation in pure and Co-doped Bi12GeO20 single crystals

2015 ◽  
Vol 05 (03) ◽  
pp. 1550023 ◽  
Author(s):  
C. Filipič ◽  
A. Klos ◽  
M. Gajc ◽  
D. A. Pawlak ◽  
J. Dolinšek ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Single Crystals ◽  
Dielectric Constants ◽  
Complex Dielectric Constant ◽  
Spectroscopy Study ◽  
Potential Barriers ◽  
Thermally Activated ◽  
Electrical Conductivities ◽  
Co Nanoparticles ◽  
Co Doped

We report the results of investigation of dielectric spectroscopy study of single crystals of [Formula: see text] and [Formula: see text] doped with Co nanoparticles. The complex dielectric constant was measured in the temperature interval from 5 to 450 K and frequencies from 1 Hz to 1 MHz. The electrical conductivity of both samples was thermally activated with potential barriers of 0.55 eV and 0.59 eV, respectively. Doped samples had bigger complex dielectric constants and [Formula: see text] exhibited slightly steeper temperature dependence than in the pure sample. The dielectric relaxation was observed in pure and doped single crystals and relaxation frequencies showed similar activation energies as electrical conductivities.

Low Frequency Dielectric Relaxation and Charge Transport in Bi12TiO20 Photorefractive Sillenite Crystals

2017 ◽  
Vol 753 ◽  
pp. 163-167
Author(s):  
Rene Alejandro Castro ◽  
Nadezhda Ivanovna Anisimova ◽  
Liliya Ansafovna Nabiullina ◽  
Evgeny Borisovich Shadrin
Keyword(s):  
Charge Transport ◽  
Dielectric Relaxation ◽  
Transport Mechanism ◽  
Low Frequency ◽  
Frequency Range ◽  
Thermally Activated ◽  
Relaxation Polarization ◽  
Polarization Mechanism ◽  
Frequency Relaxation ◽  
Thermally Activated Process

Features of processes of a dielectric relaxation and charge transport in photorefractive sillenite crystals Bi12TiO20 at low frequency range are investigated. It was found that the dispersion of dielectric permittivity ε' in crystals Bi12TiO20 is characterized by its growth with lowering frequency and rising temperature. This behaviour may be related to existence of dipole-relaxation polarization mechanism. The frequency dependence of dielectric loss tgδ reveals the existence of low frequency relaxation peaks in the studied temperature range. From the conductivity dependence on the frequency and temperature it was found that conductivity σ increases as frequency increases in the low frequency range. The observed dependence σ(ω)≈Аωs indicates that transport mechanism is due to hopping of carriers via localized electron states. The charge transport is thermally activated process in which activation energy Ea = (0.82±0.03) eV.

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