Application of impedance spectroscopy in exploring electrical properties of dielectric materials under high pressure

Abstract

Impedance spectroscopy (IS) is an indispensable method of exploring electrical properties of materials. In this review, we provide an overview on the specific applications of IS measurement in the investigations of various electrical properties of materials under high pressure, including electric conduction in bulk and grain boundary, dielectric properties, ionic conduction, and electrostrictive effect. Related studies are summarized to demonstrate the method of analyzing different electrical transport processes with various designed equivalent circuits of IS and reveal some interesting phenomena of electrical properties of materials under high pressure.

Pressure-Induced Li+ Migration and Second-Order Phase Transition in LiNbO3: Yb/Er Nanocrystals Revealed by Variable-Pressure Optical and Impedance Studies

“…There is an apparent decrease by a magnitude of 6 orders in D i / D 0 when pressure is elevated to ∼ 6 GPa, evidencing the huge effect of the interface on ion migration in addition to the unavoidable effects of structure defects and sheer strain. Although the impedance spectroscopy can be easily influenced by the parasite impedance and mixed conductive carriers besides ions, impedance contributed by ion migration could be extracted via fitting the Warburg spike line in the low-frequency range . The frequency of inflection point in the fitted spike lines of the Warburg coefficient moves to lower values with increase of pressure (prior to phase transition, see Table ), which is consistent with previous reports .…”

“…Hence, it should be caused by the interface effect of LN-YE NCs, probably owing to fracture of the symbiotic catenuliform NCs. The diffusion coefficient of Li + ions ( D i ) is expressed by the following formula D i = 0.5 ( R T / A F 2 σ C ) 2 σ is the Warburg coefficient and can be acquired from the slope of the ( Z ′ – ω –1/2 ) plot at low frequencies (the fitting results are shown in Figure S3). , R is the gas constant (8.314 J mol –1 K –1 ), T is the temperature, A is the electrode area, F is Faraday’s constant (96,500 C mol –1 ), and C is the molar concentration of Li + cations and supposed to be constant at varying pressure.…”

“…Hence, it should be caused by the interface effect of LN-YE NCs, probably owing to fracture of the symbiotic catenuliform NCs. The diffusion coefficient of Li + ions (D i ) is expressed by the following formula48…”

Effects of high pressure on the lattice structure and electrical transport properties of BiOI

“…6(b)). The impedance spectrum shows a single-arc structure whose corresponding impedance spectrum expression is: 31 Z = 1/(1/ R + 1/ Z Q )where R and Z Q represent the transferred electron and the constant phase angle element (CPE), respectively. And Z Q is given using the following expression: Z Q = σ Q (j ω ) − n where σ Q is the coefficient of CPE, ω ( ω = 2π f ) is the angular frequency, and n is the impedance factor, 0 < n < 1.…”

Study on pressure-induced isostructural phase transition and electrical transport properties of BiOBr

“…According to the single-arc pattern, the equivalent circuit of BiOBr shows a parallel circuit consisting of a resistance ( R ) and a constant phase angle element (CPE). 24 The resistance of BiOBr shows a three-stage variation with pressure, featuring turning points at around 10.0 and 15.3 GPa, respectively (Fig. 3(h)).…”