Kubo formula for frequency dispersion of dielectric permittivity and static conductivity of the Coulomb system

2010 ◽  
Vol 375 (2) ◽  
pp. 84-87 ◽  
Author(s):  
V.B. Bobrov ◽  
S.A. Trigger ◽  
A.G. Zagorodny
Keyword(s):  
Dielectric Permittivity ◽  
Frequency Dispersion ◽  
Coulomb System ◽  
Kubo Formula ◽  
Static Conductivity

Pb-DOPING EFFECTS ON THE DIELECTRIC AND PYROELECTRIC PROPERTIES OF (Sr,Pb)TiO3 SYSTEM

2012 ◽  
Vol 02 (01) ◽  
pp. 1250005 ◽  
Author(s):  
Y. P. JIANG ◽  
X. G. TANG ◽  
Y. C. ZHOU ◽  
Q. X. LIU
Keyword(s):  
Dielectric Permittivity ◽  
Frequency Dispersion ◽  
X Ray Diffraction ◽  
Pyroelectric Properties ◽  
Doping Effects ◽  
Pyroelectric Sensors ◽  
Diffraction Patterns ◽  
Perovskite Type ◽  
Pb Doping ◽  
Perovskite Type Structure

Lead strontium titanate ( Sr 1-x Pb x) TiO 3 (0.20 ≤ x ≤ 0.45,step = 0.05) ceramics were prepared by conventional mixed oxide method. The X-ray diffraction patterns indicate that the prepared samples have perovskite-type structure. With the increase of Pb content, there is a tendency from the cubic to tetragonal structure. The scanning electron microscopy micrographs reveal that the addition of Pb can affect microstructure. The dependent temperature dielectric permittivity and dielectric loss were investigated in the frequency range from 100 Hz to 1 MHz. The maximum peak of the dielectric permittivity versus temperature curve was broadened and a frequency dispersion of the dielectric permittivity was observed for the (Sr0.8Pb0.2)TiO3 ceramics. The results obtained at the frequency of 10 kHz reveal the Curie temperature linearly increased with the lead content. The fitted curves of temperature versus inverse dielectric permittivity at 10 kHz for ( Sr 1-x Pb x) TiO3 ceramics are consistent with Curie–Weiss law. The Pyroelectric properties were also investigated. The high pyroelectric coefficients and figure of merits indicate that the SPT ceramics are potential materials for pyroelectric sensors.

scholarly journals The Dispersion of Strong Field Dielectric Permittivity in (1-x)PMN-(x)PT Ceramics

2011 ◽  
Vol 56 (4) ◽  
pp. 1199-1203 ◽  
Author(s):  
P. Wawrzała ◽  
R. Skulski
Keyword(s):  
Dielectric Permittivity ◽  
Hysteresis Loop ◽  
Electric Fields ◽  
Strong Field ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Strong Electric Fields

The Dispersion of Strong Field Dielectric Permittivity in (1-x)PMN-(x)PT CeramicsWe propose the method of analysis of the dielectric permittivity measured in very strong electric fields. The method is based on the numeric calculations of derivative fromP - Ehysteresis loop. Such investigations have been performed for PMN-PT ceramics at various temperatures and frequencies. As a result we analyze the low frequency dispersion of the strong field dielectric permittivity.

scholarly journals Debye’s temperature and heat capacity for Sr0.15Ba0.85Bi2Nb2O9 relaxor ferroelectric ceramic

2016 ◽  
Vol 06 (01) ◽  
pp. 1620001
Author(s):  
A. Peláiz-Barranco ◽  
Y. González-Abreu ◽  
P. Saint-Grégoire ◽  
J. D. S. Guerra ◽  
F. Calderón-Piñar
Keyword(s):  
Heat Capacity ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Frequency Dispersion ◽  
Freezing Temperature ◽  
Ferroelectric Ceramic ◽  
Relaxor Ferroelectric ◽  
Relaxor Behavior ◽  
Temperature Range ◽  
Glass Model

A lead-free relaxor ferroelectric, Sr[Formula: see text]Ba[Formula: see text]Bi2Nb2O9, was synthesized via solid-state reaction and the temperature-dependence of the heat capacity was measured in a wide temperature range. The dielectric permittivity was also measured between 500[Formula: see text]Hz and 5[Formula: see text]MHz in the same temperature range. No anomaly has been detected in the heat capacity curve for the whole temperature range covered in the present experiments, while broad peaks have been observed in the dielectric permittivity with high frequency dispersion. A typical relaxor behavior has been observed from the dielectric analysis. The Debye’s temperature has showed a minimum value near the freezing temperature. The results are discussed considering the spin-glass model and the high frequency dispersion, which has been observed for the studied relaxor system.

Basic models in dielectric spectroscopy of heterogeneous materials with semiconductor inclusions

2017 ◽  
Vol 13 (1) ◽  
pp. 36-57 ◽  
Author(s):  
A.S. Tonkoshkur ◽  
A.B. Glot ◽  
A.V. Ivanchenko
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Spectroscopy ◽  
Heterogeneous Systems ◽  
Heterogeneous Materials ◽  
Frequency Dispersion ◽  
Charge Carriers ◽  
Free Charge ◽  
Content Type ◽  
Dispersion Region ◽  
Semiconductor Particles

Purpose The purpose of this paper is to develop the models of the dielectric permittivity dispersion of heterogeneous systems based on semiconductors to a level that would allow to apply effectively the method of broadband dielectric spectroscopy for the study of electronic processes in ceramic and composite materials. Design/methodology/approach The new approach for determining the complex dielectric permittivity of heterogeneous systems with semiconductor particles is used. It includes finding the analytical expression of the effective dielectric permittivity of the separate semiconductor particle of spherical shape. This approach takes into account the polarization of the free charge carriers in this particle, including capturing to localized electron states. This enabled the authors to use the known equations for complex dielectric permittivity of two-component matrix systems and statistical mixtures. Findings The presented dispersion equations establish the relationship between the parameters of the dielectric spectrum and electronic processes in the structures like semiconductor particles in a dielectric matrix in a wide frequency range. Conditions of manifestation and location of the different dispersion regions of the complex dielectric heterogeneous systems based on semiconductors in the frequency axis and their features are established. The most high-frequency dispersion region corresponds to the separation of free charge carriers at polarization. After this region in the direction of reducing of the frequency, the dispersion regions caused by recharge bulk and/or surface localized states follow. The most low-frequency dispersion region is caused by recharging electron traps in the boundary layer of the dielectric matrix. Originality/value Dielectric dispersion models are developed that are associated with: electronic processes of separation of free charge carriers in the semiconductor component, recapture of free charge carriers in the localized electronic states in bulk and on the surface of the semiconductor and also boundary layers of the dielectric at the polarization. The authors have analyzed to situations that correspond applicable and promising materials: varistor ceramics and composite structure with conductive and semiconductor fillers. The modelling results correspond to the existing level of understanding of the electron phenomena in matrix systems and statistical mixtures based on semiconductors. It allows to raise efficiency of research and control properties of heterogeneous materials by dielectric spectroscopy.

scholarly journals Synchrotron radiation from a charge circulating around a cylinder with negative permittivity

2020 ◽  
Vol 34 (08) ◽  
pp. 2050065
Author(s):  
A. A. Saharian ◽  
A. S. Kotanjyan ◽  
L. Sh. Grigoryan ◽  
H. F. Khachatryan ◽  
V. Kh. Kotanjyan
Keyword(s):  
Dielectric Permittivity ◽  
Radiation Intensity ◽  
Frequency Dispersion ◽  
Negative Real Part ◽  
Nonrelativistic Limit ◽  
Positive Real Part ◽  
Negative Permittivity ◽  
Positive Real ◽  
Angular Density ◽  
A Charge

We investigate the radiation from a charged particle rotating around a dielectric cylinder with a negative real part of dielectric permittivity. For the general case of frequency dispersion in dielectric permittivity, expressions are derived for the electric and magnetic fields and for the angular density of the radiation intensity on a given harmonic. Compared with the case of a cylinder with a positive real part of the permittivity, new interesting features arise in the nonrelativistic limit and for the radiation at small angles with respect to the cylinder axis. Another feature is the appearance of sharp narrow peaks in the angular density of the radiation intensity for large harmonics. We analytically estimate the height, width and the location of these peaks. The influence of the imaginary part of dielectric permittivity on the characteristics of the peaks is discussed. The analytical results are illustrated by numerical examples. We show that the radiation intensity on a given harmonic, integrated over the angles, can be essentially amplified by the presence of the cylinder.

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