Characterization of Dielectric Particles by Impedance Spectroscopy (Part I)

Abstract

Impedance spectroscopy is an effective method to investigate physical properties of multicomponent systems so that contributions of individual components can be extracted from different sections of the spectra, which is frequency dependent. Slurries can be considered as 0–3 mixed systems containing a host liquid and dispersed particles. It was shown that low‐frequency part of impedance spectra is sensitive to dielectric properties of dispersed particles. Applicability of this technique was extended using various dielectric powders dispersed in appropriate liquids. Characterization of slurries by impedance spectroscopy through applying of equivalent circuit models allows a reliable measurement of dielectric constant of particulate materials and liquids.

Electrical Properties and Impedance Spectroscopy of Lithium Modified Potassium Sodium Niobate Ceramics

“…The relaxation times (τ ) were also calculated [5][6][7][8] from Z −f graphs using appropriate values and (2πf max τ = 1) relationship. The values and parameters were obtained from the impedance spectra of samples using fitting procedure.…”

“…In the case of a bulk polycrystalline material containing grain boundary interfacial layers, the equivalent circuit would include an additional RC unit which is connected in series to the first one. These two RC elements represent the bulk of the grains and the grain boundary [4][5][6]. Impedance data gives a semicircle when Z versus Z is plotted.…”

“…Impedance data gives a semicircle when Z versus Z is plotted. Grain and grain boundary resistance could be determined from this representation which is called the Nyquist diagram [4][5][6][7][8][9].…”

Effective dielectric constant of two phase systems: Application to mixed conducting systems

“…It was previously reported that permittivity of suspended particles e 1 can be calculated directly from the low frequency semicircle. [12][13][14][15] The low frequency semicircle appears in impedance spectra if conductivity of the host liquid is high enough to have a complete relaxation of the electrical field in the sample within the frequency range of the impedance spectrometer (0.1 Hz to 1 MHz). 12 In many practical cases, the conductivity of the host material is low so that only high frequency semicircle (or section of it) appears in real impedance spectra, so values of R 2A and CPE cannot be achieved from impedance spectra.…”

“…[8][9][10][11] Such investigations of two phase systems were performed earlier in our laboratory using suspensions of metal-oxide powders in organic solvents (slurries) by impedance spectroscopy techniques. [12][13][14] Measurements using slurries have some obvious advantages for a broader-range investigation in comparison with other types of two phase systems such as polymer-ceramic composites. It is relatively simple to control the electrical conductivity of solvents in slurries so that impedance spectroscopy techniques can be implemented more efficiently as a characterization method.…”