Giant Dielectric Relaxation in Ordered Matrix Systems Depicted by Maxwell-Garnett Formula

2006 ◽  
Vol 115 ◽  
pp. 203-208
Author(s):  
A.V. Turik ◽  
G.S. Radchenko ◽  
A.I. Chernobabov ◽  
S.A. Turik
Keyword(s):  
Dielectric Permittivity ◽  
Aspect Ratio ◽  
Dielectric Relaxation ◽  
Theoretical Consideration ◽  
Heterogeneous Medium ◽  
Relaxation Processes ◽  
Dielectric Resonance ◽  
Giant Dielectric ◽  
Static Dielectric Permittivity ◽  
The Matrix

A giant enhancement of the static dielectric permittivity and a giant dielectric relaxation in a heterogeneous medium consisting of regularly arranged spheroids distributed in the matrix and described by the Maxwell-Garnett formula were studied. The influence of the inclusions aspect ratio and their concentration is analyzed. The possibility to apply the obtained results to the theoretical consideration of different heterogeneous ferroactive materials is proved. It is shown that observation of the collective dielectric resonance in such media is impossible, and only relaxation processes are the way of obtaining unusual properties of considered materials. Some valuable formulae are derived and discussed.

Giant dielectric permittivity and dielectric relaxation behaviour in (Fe1/2Nb1/2)xTi1-xO2 ceramics

2018 ◽  
Vol 44 ◽  
pp. S186-S188
Author(s):  
Theeranuch Nachaithong ◽  
Wattana Tuichai ◽  
Pairot Moontragoon ◽  
Narong Chanlek ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Relaxation ◽  
Relaxation Behaviour ◽  
Giant Dielectric

Origin of Giant Dielectric Permittivity in CaCu3Ti4O12 Ceramics

2011 ◽  
Vol 26 (10) ◽  
pp. 1058-1062
Author(s):  
Wen-Tao HAO ◽  
Jia-Liang ZHANG ◽  
Yong-Qiang TAN ◽  
Peng ZHENG ◽  
Chun-Lei WANG
Keyword(s):  
Dielectric Permittivity ◽  
Giant Dielectric

scholarly journals Comparison of the Dielectric Properties of Ecoflex® with L,D-Poly(Lactic Acid) or Polycaprolactone in the Presence of SWCN or 5CB

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1719
Author(s):  
Patryk Fryń ◽  
Sebastian Lalik ◽  
Natalia Górska ◽  
Agnieszka Iwan ◽  
Monika Marzec
Keyword(s):  
Oleic Acid ◽  
Dielectric Properties ◽  
Polymer Matrix ◽  
Liquid Crystalline ◽  
Weight Ratio ◽  
Poly Lactic Acid ◽  
Relaxation Processes ◽  
The Matrix ◽  
Walled Carbon Nanotubes ◽  
Hybrid Layers

The main goal of this paper was to study the dielectric properties of hybrid binary and ternary composites based on biodegradable polymer Ecoflex®, single walled carbon nanotubes (SWCN), and liquid crystalline 4′-pentyl-4-biphenylcarbonitrile (5CB) compound. The obtained results were compared with other created analogically to Ecoflex®, hybrid layers based on biodegradable polymers such as L,D-polylactide (L,D-PLA) and polycaprolactone (PCL). Frequency domain dielectric spectroscopy (FDDS) results were analyzed taking into consideration the amount of SWCN, frequency, and temperature. For pure Ecoflex®, two relaxation processes (α and β) were identified. It was shown that the SWCN admixture (in the weight ratio 10:0.01) did not change the properties of the Ecoflex® layer, while in the case of PCL and L,D-PLA, the layers became conductive. The dielectric constant increased with an increase in the content of SWCN in the Ecoflex® matrix and the conductive behavior was not visible, even for the greatest concentration (10:0.06 weight ratio). In the case of the Ecoflex® polymer matrix, the conduction relaxation process at a frequency ca. several kilohertz appeared and became stronger with an increase in the SWCN admixture in the matrix. Addition of oleic acid to the polymer matrix had a smaller effect on the increase in the dielectric response than the addition of liquid crystal 5CB. Fourier transform infrared (FTIR) results revealed that the molecular structure and chemical character of the Ecoflex® and PCL matrixes remained unchanged upon the addition of SWCN or 5CB in a weight ratio of 10:0.01 and 10:1, respectively, while molecular interactions appeared between L,D-PLA and 5CB. Moreover, adding oleic acid to pure Ecoflex® as well as the binary and ternary hybrid layers with SWCN and/or 5CB in a weight ratio of Ecoflex®:oleic acid equal to 10:0.3 did not have an influence on the chemical bonding of these materials.

Relaxation processes of some simple aliphatic molecules in dilute solutions

1977 ◽  
Vol 55 (4) ◽  
pp. 297-301 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Carbon Tetrachloride ◽  
Dielectric Relaxation ◽  
Thermodynamic Parameters ◽  
Relaxation Times ◽  
Relaxation Processes ◽  
Dilute Solutions ◽  
Microwave Region ◽  
Nonpolar Solvents ◽  
Dielectric Data ◽  
Intramolecular Rotation

The dielectric relaxation processes of acetone, cyclohexanone, 4-methyl-2-pentanone, and 4-heptanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride have been studied in the microwave region over a temperature range 10 to 60 °C. The relaxation times and the thermodynamic parameters for the activated states have been determined using the measured dielectric data. The results have been discussed in terms of dipole reorientation by molecular and intramolecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.

EFFECT OF CELL THICKNESS ON THE DIELECTRIC RELAXATION PROCESSES IN FERROELECTRIC LIQUID CRYSTALS

2008 ◽  
Vol 22 (14) ◽  
pp. 2263-2273 ◽  
Author(s):  
RAJBIR SINGH ◽  
K. K. RAINA
Keyword(s):  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Dielectric Strength ◽  
Relaxation Processes ◽  
Goldstone Mode ◽  
Ferroelectric Liquid Crystal ◽  
Dielectric Relaxation Spectroscopy ◽  
Dielectric Parameters ◽  
Liquid Crystal Material ◽  
Cell Thickness

Dielectric relaxation spectroscopy in the frequency range 50 Hz to 1 MHz has been carried out in a room temperature ferroelectric liquid crystal mixture in the SmC*, SmA and N* phases in cells of different thickness. The relaxation frequency fr, distribution parameter α and dielectric strength δ∊ have been evaluated. Goldstone mode, domain mode and soft mode have been observed. It is found that the cell thickness has a significant effect on the dielectric parameters of the ferroelectric liquid crystal material. The results have been discussed.

Influence of smectic order on the static dielectric permittivity of liquid crystals

1974 ◽  
Vol 61 (5) ◽  
pp. 1985-1989 ◽  
Author(s):  
W. H. de Jeu ◽  
W. J. A. Goossens ◽  
P. Bordewijk
Keyword(s):  
Liquid Crystals ◽  
Dielectric Permittivity ◽  
Static Dielectric Permittivity
Sign in / Sign up

Export Citation Format

Share Document