Dielectric Spectroscopy of a Nanofiltration Membranes−Electrolyte Solution System: I. Low-Frequency Dielectric Relaxation from the Counterion Polarization in Pores and Model Development

The compound K3Sb5O14 was synthetisized single-phase and examined by means of dielectric spectroscopy from 30 Hz to 10 MHz. Three separate regions of dielectric absorption with broad distributions of relaxation times have been found. Temperature-dependend measurements up to 200 °C yielded enthalpies of activation between 15 and 20 kcal/mole.

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Compensation phenomena in oil-resin mixtures: A new dielectric approach to percolative processes

Journal of Materials Research ◽

10.1557/jmr.1997.0371 ◽

1997 ◽

Vol 12 (10) ◽

pp. 2784-2793 ◽

Cited By ~ 2

Author(s):

O. Pagés ◽

A. Lamure ◽

C. Lacabanne ◽

M. Odlyha ◽

D. Craig

Keyword(s):

Dielectric Relaxation ◽

Dielectric Spectroscopy ◽

Low Frequency ◽

Relaxation Processes ◽

Thermally Stimulated Currents ◽

Critical Concentrations ◽

Composite Systems ◽

Percolation Phenomena ◽

Percolation Thresholds ◽

First Time

The methods of thermally stimulated currents (TSC) together with low frequency dielectric spectroscopy (LFDS) are combined for the first time to study percolation phenomena. These take place within oil-resin mixtures which constitute conductor/insulator-like composite systems. Each of these techniques is shown to describe selectively one of two different kinds of relaxation processes in the oil component: first, anelastic dipolar movements and second, the circulation of free charges. The separate qualitative interpretations of the combined TSC/LFDS experiments lead to convergent estimations of the percolation thresholds of the two basic materials in oil-resin mixtures. The latter appear as critical concentrations for which the dielectric relaxation processes either comply suddenly with compensation laws or pre-existing compensation phenomena change in nature.

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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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Broadband dielectric spectroscopy for monitoring temperature-dependent chloride ion motion in BiOCl plates

Scientific Reports ◽

10.1038/s41598-020-79018-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Adrian Radoń ◽

Dariusz Łukowiec ◽

Patryk Włodarczyk

Keyword(s):

Electrical Conductivity ◽

Dielectric Spectroscopy ◽

Low Frequency ◽

Chloride Ion ◽

Ion Source ◽

Chloride Ions ◽

Ion Concentration ◽

Broadband Dielectric Spectroscopy ◽

Free Chloride ◽

Structure Rebuilding

AbstractThe dielectric properties and electrical conduction mechanism of bismuth oxychloride (BiOCl) plates synthesized using chloramine-T as the chloride ion source were investigated. Thermally-activated structure rebuilding was monitored using broadband dielectric spectroscopy, which showed that the onset temperature of this process was 283 K. This rebuilding was related to the introduction of free chloride ions into [Bi2O2]2+ layers and their growth, which increased the intensity of the (101) diffraction peak. The electrical conductivity and dielectric permittivity were related to the movement of chloride ions between plates (in the low-frequency region), the interplanar motion of Cl− ions at higher frequencies, vibrations of these ions, and charge carrier hopping at frequencies above 10 kHz. The influence of the free chloride ion concentration on the electrical conductivity was also described. Structure rebuilding was associated with a lower concentration of free chloride ions, which significantly decreased the conductivity. According to the analysis, the BiOCl plate conductivity was related to the movement of Cl− ions, not electrons.

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