Frequency-dependent activation energy of ac-conductivity in poly(4,4′-N,N-diiminosulphoxide diaminophenyl ether)

1991 ◽  
Vol 27 (3) ◽  
pp. 311-314 ◽  
Author(s):  
M. A. Soliman ◽  
F. M. Reicha ◽  
A. M. Shaban
Keyword(s):  
Activation Energy ◽  
Ac Conductivity ◽  
Frequency Dependent

Study on Low Temperature Conduction Mechanism of Al Doped ZnO/SiO2/ P-Si Heterojunction

2021 ◽  
Vol 904 ◽  
pp. 363-368
Author(s):  
Xiao Yan Zhou ◽  
Bang Sheng Yin
Keyword(s):  
Activation Energy ◽  
Impedance Spectroscopy ◽  
Low Temperature ◽  
Grain Boundaries ◽  
Ac Conductivity ◽  
Spray Pyrolysis Method ◽  
Temperature Conductivity ◽  
Calculated Activation Energy ◽  
Doped Zno ◽  
Temperature Conduction

The 3 at% Al doped ZnO thin films were deposited on p-Si substrate with a native SiO2 layer by spray pyrolysis method. Low temperature conduction behaviors were studied by analysis of impedance spectroscopy and low temperature ac conductivity. The results of impedance spectroscopy showed that the grain boundaries contributed to the resistivity of Al doped ZnO/SiO2/p-Si heterojunction. The calculated activation energy was 0.073 eV for grain boundaries. The equivalent circuit to demonstrate the electrical properties of Al doped ZnO/SiO2/p-Si heterojunction was a series connection of two parallel combination circuits of a resistor and a universal capacitor. Low temperature ac conductivity measurements indicated that the conductivity increased with temperature. Low temperature conductivity mechanism was electron conductivity, and the activation energy was 0.086 eV.

scholarly journals DC and AC Conductivity in Polymeric Particulate Composites of Epoxy Resin and Metal Particles

1999 ◽  
Vol 8 (1) ◽  
pp. 096369359900800 ◽  
Author(s):  
G.M. Tsangaris ◽  
G.C. Psarras ◽  
E. Manolakaki
Keyword(s):  
Activation Energy ◽  
Epoxy Resin ◽  
Ac Conductivity ◽  
Critical Frequency ◽  
Nickel Powder ◽  
Temperature Shift ◽  
Conductive Filler ◽  
Particulate Composites ◽  
Nickel Particles ◽  
Dc And Ac Conductivity

The DC and AC conductivity of composites with epoxy resin and nickel particles was investigated for various content of nickel powder from ambient to 120 °C. AC conductivity was measured in the frequency range 10 Hz to 13 MHz. An enhancement of conductivity was evidenced increasing conductive filler content and temperature. AC conductivity was found to be frequency dependent beyond a critical frequency ω c. The activation energy of the temperature shift of ω c was compared to the activation energy of DC conductivity.

scholarly journals Universal frequency-dependent ac conductivity of conducting polymer networks

2007 ◽  
Vol 91 (12) ◽  
pp. 122911 ◽  
Author(s):  
A. N. Papathanassiou ◽  
I. Sakellis ◽  
J. Grammatikakis
Keyword(s):  
Conducting Polymer ◽  
Ac Conductivity ◽  
Polymer Networks ◽  
Frequency Dependent

Dielectric Properties of Polyester Reinforced with Carbon Black Particles

2011 ◽  
Vol 110-116 ◽  
pp. 170-176
Author(s):  
Omed Ghareb Abdullah ◽  
Dana Abdull Tahir ◽  
Gelas Mukaram Jamal ◽  
Salah Raza Saeed
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Carbon Black ◽  
Low Temperatures ◽  
Ac Conductivity ◽  
Low Frequency ◽  
Frequency Range ◽  
Exponential Factor ◽  
Increasing Temperature ◽  
Dielectric Permittivity And Loss

Dielectric constant and ac conductivity of Polyester doped with carbon black are investigated in the frequency range (0.5-103) KHz and within the temperature range (26-80) oC. Dielectric permittivity and loss tangent reduced with increasing frequency and increase with increasing temperature. The ac conductivity σac for all samples were found to be weak frequency dependent at low frequency, however vary with frequency as a power law ωs at higher frequency range. The variation of frequency exponential factor s between 0.63 and 0.77, indicates a dominant hopping process at low temperatures. From the temperature dependence of dc conductivity, the increase of activation energy was observed with carbon black concentrations.

Dielectric Behavior and Impedance Spectroscopy of Bi2Sr2GdCu2Oy

2003 ◽  
Vol 17 (21) ◽  
pp. 3847-3856 ◽  
Author(s):  
M. Chandrasekhar
Keyword(s):  
Activation Energy ◽  
Temperature Region ◽  
Ac Conductivity ◽  
Room Temperature ◽  
Complex Impedance ◽  
Frequency Dispersion ◽  
Solid State Reaction Method ◽  
Dielectric Behavior ◽  
Nominal Composition ◽  
Present System

Samples with the nominal composition Bi 2 Sr 2 GdCu 2 O y in Bi -2212 where Gd replaces Ca as well as samples without Gd were prepared by solid-state reaction method. From the room temperature X-ray diffraction data, the samples were found to be similar to the single phase Bi -2212 structure. Impedance studies were performed from room temperature to 423 K at different frequencies in the range of 10 to 700 KHz. The AC conductivity increases with temperature and frequency, exhibiting frequency dispersion at low temperature region. The activation energy from AC conductivity in the high temperature region is found to be 0.432 eV. The permitivity increases with the increase in temperature and at 373 K it shows a maximum value exhibiting a dielectric loss. Complex impedance spectra are analyzed in terms of bulk relaxation and interfacial effects. The activation energy of the dipoles involved in the relaxation was estimated to be 0.482 eV. The universal power law of Jonscher is verified in the present system.

scholarly journals Dielectric relaxation and study of electrical conduction mechanism in BaZr0.1Ti0.9O3 ceramics by correlated barrier hopping model

2018 ◽  
Vol 36 (1) ◽  
pp. 112-122 ◽  
Author(s):  
Tanusree Mondal ◽  
Sayantani Das ◽  
T.P. Sinha ◽  
P.M. Sarun
Keyword(s):  
Activation Energy ◽  
Dielectric Relaxation ◽  
Electrical Conduction ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Dielectric Material ◽  
Relaxation Processes ◽  
Cole Plot ◽  
Electrical Conduction Mechanism ◽  
Correlated Barrier Hopping

AbstractThis work aims to study the electrical conduction mechanism in the dielectric material BaZr0.1Ti0.9O3(BZT) ceramics by applying AC signal in the frequency range of 102Hz to 106Hz. The phase purity and microstructure of the sample have been studied by X-ray diffraction refinement and field-emission scanning electron microscope (FE-SEM) analysis. The appearance of resonance peaks in the loss tangent at high temperature is due to inherent dielectric relaxation processes of this oxide. The temperature dependent Cole-Cole plot has been studied in details to determine both the grain and grain boundary contribution to the conductivity. Electrical modulus analysis reveals that the hopping of charge carriers is the most probable conduction mechanism in BZT ceramics. The obtained data of AC conductivity obey the universal double power law and have been discussed in terms of microstructural network characteristics. The behavior of frequency exponent n of AC conductivity as a function of temperature verify the applicability of the correlated barrier hopping (CBH) model. The AC conductivity data are used to estimate the minimum hopping length, density of states at Fermi level, thermal conductivity and apparent activation energy. The value of activation energy confirms that the oxygen vacancies play a vital role in the conduction mechanism.

scholarly journals Dielectric and AC Conductivity Studies in PPy-Ag Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
K. Praveenkumar ◽  
T. Sankarappa ◽  
J. S. Ashwajeet ◽  
R. Ramanna
Keyword(s):  
Activation Energy ◽  
Silver Nanoparticles ◽  
Dielectric Properties ◽  
Ac Conductivity ◽  
Conductivity Data ◽  
Chemical Route ◽  
Polaron Hopping ◽  
Dielectric Data ◽  
First Time ◽  
Hopping Model

Polypyrrole and silver nanoparticles have been synthesized at 277 K by chemical route. Nanoparticles of polypyrrole-silver (PPy-Ag) composites were prepared by mixing polypyrrole and silver nanoparticles in different weight percentages. Dielectric properties as a function of temperature in the range from 300 K to 550 K and frequency in the range from 50 Hz to 1 MHz have been measured. Dielectric constant decreased with increase in frequency and temperature. Dielectric loss decreased with increase in frequency and increased with increase in temperature. Using dielectric data AC conductivity has been determined. Conductivity was found to be in the order of 10−3 (Ω−1 m−1) and it increased with increase in temperature. Temperature variation of conductivity data has been analyzed in the light of Mott’s polaron hopping model. Activation energy for conduction has been determined. Activation energy was determined to be in the order of meV and it has increased with increase in frequency and Ag nanoparticles content. This is the first time that PPy-Ag nanocomposites have been investigated for dielectric properties and AC conductivity and data analyzed thoroughly.

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