Fox function representation of non-debye relaxation processes

1993 ◽  
Vol 71 (3-4) ◽  
pp. 741-757 ◽  
Author(s):  
Walter G. Gl�ckle ◽  
Theo F. Nonnenmacher
Keyword(s):  
Relaxation Processes ◽  
Debye Relaxation ◽  
Function Representation

scholarly journals Диэлектрическая релаксация в тонких слоях стеклообразной системы Ge-=SUB=-28.5-=/SUB=-Рb-=SUB=-15-=/SUB=-S-=SUB=-56.5-=/SUB=-

2018 ◽  
Vol 52 (8) ◽  
pp. 912
Author(s):  
Р.А. Кастро ◽  
Н.И. Анисимова ◽  
А.А. Кононов
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Structural Parameters ◽  
Glass Structure ◽  
Relaxation Processes ◽  
Glassy System ◽  
Debye Relaxation ◽  
Molecular Dipole ◽  
Cole Model ◽  
Charged Defects

AbstractThe results of studying dielectric relaxation processes in the Ge_28.5Pb_15S_56.5 glassy system are presented. The existence of the non-Debye relaxation process caused by the distribution of relaxors over the relaxation time according to the Cole–Cole model is revealed. The energy and structural parameters are calculated: the activation energy E _ p = 0.40 eV and the molecular dipole moment μ = 1.08 D. The detected features are explained within the model according to which the chalcogenide-glass structure is a set of dipoles formed by charged defects such as D ^+ and D ^–.

Near-Debye relaxation processes in La1−xSrxMnO3

2001 ◽  
Vol 13 (19) ◽  
pp. 4359-4366
Author(s):  
Z C Xia ◽  
C Q Tang ◽  
D X Zhou
Keyword(s):  
Relaxation Processes ◽  
Debye Relaxation

scholarly journals Preparation of SiO2-MnFe2O4 Composites via One-Pot Hydrothermal Synthesis Method and Microwave Absorption Investigation in S-Band

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2605 ◽  
Author(s):  
Yin ◽  
Zhang ◽  
Wang ◽  
Feng ◽  
Zhao ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Microwave Absorption ◽  
Impedance Matching ◽  
Synthesis Method ◽  
Phase Identification ◽  
Relaxation Processes ◽  
Potential Candidate ◽  
One Pot ◽  
Debye Relaxation ◽  
Attenuation Characteristic

MnFe2O4 NPs are successfully decorated on the surface of SiO2 sheets to form the SiO2-MnFe2O4 composite via one-pot hydrothermal synthesis method. The phase identification, morphology, crystal structure, distribution of elements, and microwave absorbing properties in S-band (1.55~3.4 GHz) of the as-prepared composite were investigated by XRD, SEM, TEM, and Vector Network Analyzer (VNA) respectively. Compared with the pure MnFe2O4 NPs, the as-prepared SiO2-MnFe2O4 composite exhibits enhanced microwave absorption performance in this frequency band due to the strong eddy current loss, better impedance matching, excellent attenuation characteristic, and multiple Debye relaxation processes. The maximum reflection loss of −14.87 dB at 2.25 GHz with a broader −10 dB bandwidth over the frequency range of 1.67~2.9 GHz (1.23 GHz) can be obtained at the thickness of 4 mm. Most importantly, the preparation method used here is relatively simple, hence such composite can be served as a potential candidate for effective microwave absorption in S-band.

Multifractal phase transitions in the non-Debye relaxation processes

2000 ◽  
Vol 62 (3) ◽  
pp. 3293-3298 ◽  
Author(s):  
Alexander Leyderman ◽  
Shi-Xian Qu
Keyword(s):  
Phase Transitions ◽  
Relaxation Processes ◽  
Debye Relaxation

High-Temperature Dielectric Properties of Goethite From 400 to 3000 MHz

2005 ◽  
Vol 20 (1) ◽  
pp. 18-29 ◽  
Author(s):  
C.A. Pickles ◽  
J. Mouris ◽  
R.M. Hutcheon
Keyword(s):  
Dielectric Properties ◽  
Thermogravimetric Analysis ◽  
Perturbation Technique ◽  
Relaxation Times ◽  
Relaxation Processes ◽  
Heating Rates ◽  
Hydrogen Atoms ◽  
Debye Relaxation ◽  
The Real ◽  
Thermally Activated

The dielectric properties of goethite and, in particular, the changes during the topotactic conversion of goethite to hematite were studied from room temperature to about 800 °C in the frequency range of 400 to 3000 MHz using the cavity perturbation technique. The complex permittivity, that is, both the real and the imaginary or absorptive parts (έ and ἕ), were measured under various heating regimens. In addition, thermogravimetric analysis (TGA) was performed to characterize the transformation of goethite to hematite. The Debye relaxation formalism was applied to the processes occurring both during and after the main dehydroxylation reaction to calculate the relaxation times. The Arrhenius equation for thermally activated relaxation times was used to determine the activation energies. Both the real and the absorptive parts of the permittivity exhibited a significant peak during the main part of the goethite to hematite decomposition reaction. Above the transformation, there was another, less dramatic, thermally activated increase in the permittivity values. The increase in the permittivities during the goethite to hematite transformation was attributed to the formation of quasi-free migrating radicals, for example, hydroxyl ions, oxygen ions, or hydrogen atoms, during the dehydroxylation of goethite. The derivative thermogravimetric analysis (DTGA) curve was found to be directly related to the transient values of the real and the imaginary permittivities. Higher heating rates resulted in an accelerated rate of dehydroxylation and therefore higher values of the transient permittivities. In the temperature range of 400 °C to 500 °C (i.e., just above the dehydroxylation peak), the real permittivity exhibited a varying frequency dependence, which suggested that changes were occurring in the newly formed, highly defected hematite structure, which is referred to as hydrohematite. During the reaction there were multiple relaxation processes and thus the Debye relationship could not be applied. However, at temperatures above about 500 °C, the structure stabilized, the Debye relationship was more closely followed, and the relaxation times could be determined as a function of temperature. The activation energy for the relaxation process above 500 °C was determined to be 0.47 kJ/mol.

Dielectric Relaxation Studies of the Fast Lithium-Ion Conductor La2/3-xLi3xTiO3 (x=0.06, 0.11)

2012 ◽  
Vol 457-458 ◽  
pp. 1019-1024
Author(s):  
Wei Guo Wang ◽  
Qian Feng Fang ◽  
Gang Ling Hao
Keyword(s):  
Dielectric Relaxation ◽  
Phonon Frequency ◽  
Lithium Ion ◽  
Relaxation Processes ◽  
Ion Diffusion ◽  
Lithium Ions ◽  
Debye Relaxation ◽  
Exponential Factor ◽  
Relaxation Parameters ◽  
Lithium Ion Diffusion

The diffusion processes of lithium ions in La2/3-xLi3xTiO3 (x=0.06, 0.11) compounds were investigated by dielectric relaxation method. Prominent relaxation dielectric loss peaks, peaks P1 and P2 in La0.56Li0.33TiO3 and peaks P3 and P4 in La0.61Li0.18 TiO3, were observed. From the shift of peak position with frequency, the activation energy of 0.36~0.42 eV and the pre-exponential factor of relaxation time in the order of 10-14 ~ 10-13 s were obtained if one assumes Debye relaxation processes. The activation energies of lithium ion diffusion in La2/3-xLi3xTiO3 compounds and the characteristic vibration frequency for the ionic hopping motion are higher than those measured by 7Li nuclear magnetic resonance (NMR) spectroscopy and that of the typical phonon frequency (about 1013Hz). These values of relaxation parameters strongly suggest the existence of interaction between the relaxation species (here lithium ions or vacancies). Basing on the coupling model, the decoupled relaxation parameters of the dielectric relaxation peaks is: P1 (0.14 eV, 2×10-13 s), P2 (0.25 eV, 1.8×10-13 s), P3 (0.17 eV, 4×10-13 s) and P4 (0.3 eV, 2.7×10-13 s). These decoupled parameters are very close to the NMR measurement results and the reciprocal of the typical phonon frequency. Judging from the relaxation parameter of the peaks and combining with the crystallographic characterization, it is suggested that the P1 (P3) and P2 (P4) peaks are associated with the lithium ion diffusion in the ab planes and between the adjacent ab planes, respectively.

The effect of conductivity on describing the non-debye relaxation processes in dielectrics

2010 ◽  
Vol 74 (9) ◽  
pp. 1212-1213 ◽  
Author(s):  
A. S. Bogatin ◽  
A. V. Turik ◽  
S. A. Kovrigina ◽  
E. V. Andreev
Keyword(s):  
Relaxation Processes ◽  
Debye Relaxation
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