Dielectric and AC Conductivity Studies in PPy-Ag Nanocomposites

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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Dielectric, Thermal and FTIR Studies of Cobalt Doped Magnesium Hydrogen Maleate Hexahydrate Single Crystals

Material Science Research India ◽

10.13005/msri/080112 ◽

2011 ◽

Vol 8 (1) ◽

pp. 91-96

Author(s):

B. Rajagopal ◽

M. V. Ramana ◽

A. V. Sarma

Keyword(s):

Activation Energy ◽

Dielectric Constant ◽

Dielectric Properties ◽

Melting Point ◽

Transition Metal ◽

Single Crystals ◽

Loss Tangent ◽

Transition Metal Ions ◽

Ftir Studies ◽

First Time

Present work reports the dielectric, thermal and FTIR studies of Co2+: MHMH single crystal for the first time. The influence of addition of transition metal ions on the dielectric properties, like dielectric constant, loss tangent,a.c. conductivity and activation energy of these crystals was discussed. FTIR studies confirm the presence of carboxylate ions. The melting point of the sample and final product after decomposition are studied using TG/DTA.

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DIELECTRIC STUDIES IN Li2O AND CoO DOPED BOROPHOSPHATE GLASSES

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v8i3.1485 ◽

2015 ◽

Vol 8 (3) ◽

pp. 2256-2266 ◽

Cited By ~ 2

Author(s):

Sankarappa Talari ◽

J. S. Ashwajeet ◽

R. Ramanna ◽

K. Praveenkumar

Keyword(s):

Activation Energy ◽

Dielectric Properties ◽

Small Polaron ◽

Relaxation Mechanism ◽

Frequency Exponent ◽

Polaron Hopping ◽

Borophosphate Glasses ◽

Quantum Mechanical Theory ◽

Quenching Method ◽

Hopping Models

Borophosphate glasses in the compositions, (B2O3)0.2 . (P2O5)0.3 . (Li2O) 0.5-X . (CoO) X, wherex = 0.05, 0.1, 0.15, 0.25, 0.30, 0.35, 0.40 and 0.45 were prepared at 1400K by following melt quenching method. Their amorphous nature was confirmed by XRD studies and was investigated for dielectric properties in the frequency range from 100Hz to 1MHz and temperature range from 300K to 573K. The conductivity was derived from the dielectric spectrum. The frequency exponent, s, dc and ac components of the conductivity were determined. The temperature dependence of conductivity at different frequencies was analyzed using Mottâ€™s small polaron hopping model, and the high temperature activation energy has been estimated and discussed. The variation of conductivity and activation energy with composition revealed a changeover of conduction mechanism from predominantly ionic to electronic regime for mole fractions of CoO between 0.3 and 0.35. This is a new result. Huntâ€™s model has been employed to analyze frequency dependence of conductivity. Relaxation features of the dielectric properties have been extracted from the analysis of electric moduli with frequency. Activation energy for relaxation mechanism has been determined. Frequency exponent was found to be temperature dependent. Quantum mechanical theory and correlated barrier hopping models were found to be inadequate to explain frequency exponent behavior with temperature.For the first time that borophosphate glasses doped with Li2O and CoO were studied for dielectric properties and ac conductivity as a function of temperature and frequency and the data has been analysed thoroughly.Â

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Preparation, Structural, Optical, Electrical, and Magnetic Characterisation of Orthorhombic GdCr0.3Mn0.7O3 Multiferroic Nanoparticles

Zeitschrift für Naturforschung A ◽

10.1515/zna-2016-0284 ◽

2017 ◽

Vol 72 (1) ◽

pp. 87-95

Author(s):

Deepa Singh ◽

K.K. Bamzai

Keyword(s):

Activation Energy ◽

Ac Conductivity ◽

Room Temperature ◽

Magnetic Behaviour ◽

X Ray Diffraction ◽

Orthorhombic Crystal ◽

Sem Images ◽

Chemical Route ◽

Orthorhombic Crystal Structure ◽

Universal Power Law

AbstractIn this article, chromium-doped gadolinium manganate (GdCr0.3Mn0.7O3) nanoparticles has been prepared by wet-chemical route in order to investigate their structural, optical, electrical, and room temperature magnetic properties. Microstructural and compositional analyses have been carried out by X-ray diffraction and scanning electron microscopy (SEM). Synthesised material is found to be in orthorhombic crystal structure with Pbnm space group. The spherical morphology of the nanoparticles has been examined from the SEM images. Functional groups have been identified using Fourier transform infrared spectroscopy. Dielectric constant, dielectric loss, AC conductivity (σac), and activation energy in the range of 1 kHz–1 MHz from room temperature to high temperature (400°C) have been investigated. The frequency dependence of AC conductivity obeys the universal power law. The value of activation energy depends on increase in frequency. Room temperature magnetic behaviour suggests the material to be paramagnetic in nature.

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Dielectric Properties, AC Conductivity, and Electric Modulus Analysis of Bulk Ethylcarbazole-Terphenyl

Advances in Materials Science and Engineering ◽

10.1155/2020/8689150 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Hussam Bouaamlat ◽

Nasr Hadi ◽

Najat Belghiti ◽

Hayat Sadki ◽

Mohammed Naciri Bennani ◽

...

Keyword(s):

Dielectric Properties ◽

Ac Conductivity ◽

Conduction Mechanism ◽

Electric Modulus ◽

X Ray Diffraction ◽

X Ray ◽

Universal Power Law ◽

Electrical And Dielectric Properties ◽

Increasing Temperature ◽

Hopping Model

Electrical and dielectric properties for bulk ethylcarbazole-terphenyl (PEcbz-Ter) have been studied over frequency range 1 kHz–2 MHz and temperature range (R.T –120°C). The copolymer PEcbz-Ter was characterised by using X-ray diffraction. The frequency dependence of the dielectric constant (εr′) and dielectric loss (εr″) has been investigated using the complex permittivity. εr′ of the copolymer decreases with increasing frequency and increases with temperature. AC conductivity (σac) data were analysed by the universal power law. The behaviour of σac increases with increasing temperature and frequency. The change of the frequency exponent (s) with temperature was analysed in terms of different conduction mechanisms, and it was found that the correlated barrier-hopping model is the predominant conduction mechanism. The electric modulus was used to analyze the relaxation phenomenon in the material.

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Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v8i3.1496 ◽

2015 ◽

Vol 8 (3) ◽

pp. 2176-2188 ◽

Cited By ~ 4

Author(s):

Keisham Nanao Singh

Keyword(s):

Activation Energy ◽

Silver Nanoparticles ◽

Liquid Crystal ◽

Dielectric Relaxation ◽

Relaxation Process ◽

Relaxation Times ◽

Low Frequency ◽

Bulk Liquid ◽

Molecular Rearrangement ◽

Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

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