On the Physical Meaning of Disperse Parameters of Frequency Dependence of Dielectric Permittivity in the Havriliak–Negami Model

Volkov, A. S.; Koposov, G. D.; Perfiliev, R. O.

doi:10.1134/s0030400x18090242

Cited by 14 publications

(8 citation statements)

References 6 publications

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“…However, regardless of the approach, it remains difficult to separate processes with similar relaxation times and to explain the dynamics of the polar nanoregions. Havriliak and Negami proposed corrections to the Debye equation (Equation (3)), describing the disordered systems by the empirical formulae [ 55 ] as follows:

where the asymmetry (

) and broadening (

) parameters,

, are introduced to model the dielectric spectra [ 55 , 56 , 57 ].…”

Section: Resultsmentioning

confidence: 99%

Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals

et al. 2021

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The frequency and temperature dependence of dielectric properties of CH3NH3PbI3 (MAPI) crystals have been studied and analyzed in connection with temperature-dependent structural studies. The obtained results bring arguments for the existence of ferroelectricity and aim to complete the current knowledge on the thermally activated conduction mechanisms, in dark equilibrium and in the presence of a small external a.c. electric field. The study correlates the frequency-dispersive dielectric spectra with the conduction mechanisms and their relaxation processes, as well as with the different transport regimes indicated by the Nyquist plots. The different energy barriers revealed by the impedance spectroscopy highlight the dominant transport mechanisms in different frequency and temperature ranges, being associated with the bulk of the grains, their boundaries, and/or the electrodes’ interfaces.

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where the asymmetry (

) and broadening (

) parameters,

, are introduced to model the dielectric spectra [ 55 , 56 , 57 ].…”

Section: Resultsmentioning

confidence: 99%

Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals

et al. 2021

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“…As an approximating function in the calculations, the Havriliak-Negami function was used (Volkov et al 2018) in the form (8).…”

Section: Experimental Results With Their Preliminary Analysismentioning

confidence: 99%

Polarization processes in silver iodide films near the superionic phase transition temperature

Ilinskiy

Shadrin

Castro

et al. 2022

PCS

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The article reports the results of dielectric spectroscopy analysis exploring polarization processes in silver iodide nanocrystalline films in the region of thermal superionic phase transition. It also provides calculations of the system's relaxation and energy parameters. The abrupt change of parameters at the transition point is demonstrated by activation energy of semiconductor conduction and commit phases, indicator of the degree of frequency dependence of conductivity, and the maximum value of the function of the tangent of the dielectric loss angle. The article proposes a model of the micro-mechanism of the thermal phase transition from a semiconductor to a superionic state. It is shown that, along with the superionic phase transition, films undergo a percolation phase transition with the formation of a two-dimensional percolation cluster.

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“…The relaxation curves ε ″ = f (ν) were approximated within the Havriliak-Negami approach [ 57 , 58 , 59 ]:

where ε is the dielectric permittivity, ω is the frequency,

is the dielectric permittivity at ω → ∞, τ is the relaxation time, and α and β are some parameters of frequency dispersion. The Havriliak-Negami approach is often considered as a generalization of previous models for the frequency dispersion of the dielectric permittivity [ 59 ]: for α = 0 and β = 1, Formula (1) transforms into the Debye model; for 1 > α > 0 and β = 1—the Cole-Cole model; for α = 0 and 1 > β > 1—Formula (1) turns into the Davidson-Cole model. …”

Section: Resultsmentioning

confidence: 99%

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

et al. 2021

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The spectra of dielectric relaxation of macroporous silicon with a mesoporous skin layer in the frequency range 1–106 Hz during cooling (up to 293–173 K) and heating (293–333 K) are presented. Macroporous silicon (pore diameter ≈ 2.2–2.7 μm) with a meso-macroporous skin layer was obtained by the method of electrochemical anodic dissolution of monocrystalline silicon in a Unno-Imai cell. A mesoporous skin layer with a thickness of about 100–200 nm in the form of cone-shaped nanostructures with pore diameters near 13–25 nm and sizes of skeletal part about 35–40 nm by ion-electron microscopy was observed. The temperature dependence of the relaxation of the most probable relaxation time is characterized by two linear sections with different slope values; the change in the slope character is observed at T ≈ 250 K. The features of the distribution of relaxation times in meso-macroporous silicon at temperatures of 223, 273, and 293 K are revealed. The Havriliak-Negami approach was used for approximation of the relaxation curves ε″ = f(ν). The existence of a symmetric distribution of relaxers for all temperatures was found (Cole-Cole model). A discussion of results is provided, taking into account the structure of the studied object.

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On the Physical Meaning of Disperse Parameters of Frequency Dependence of Dielectric Permittivity in the Havriliak–Negami Model

Cited by 14 publications

References 6 publications

Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals

Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals

Polarization processes in silver iodide films near the superionic phase transition temperature

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

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