Correlated ion hopping in single-crystal yttria-stabilized zirconia

Abstract

A study of the effect of correlated ion motion on the electrical conductivity relaxation in single-crystalline yttria-stabilized zirconia is presented. Complex admittance in the radio frequency range show power-law dependencies in the real part of the conductivity at high frequencies of the form n and asymmetric electric modulus plots as a result of correlations. An analysis of the frequency dependence of the electric modulus is conducted to obtain time decay functions of the form exp͓Ϫ(t/ ) ␤ ͔ from an analytical distribution of relaxation times. Correlation times, and parameters n and ␤ characterizing the relaxation in time and frequency domains are compared to show the equivalence of time and frequency representations. The common origin of ac and dc processes is discussed in view of the frequency dependence of the complex conductivity. From a macroscopic activation energy for ion motion Eϭ1.16 eV and a ␤ value of 0.43, a single-ion microscopic activation energy E a ϭ0.5 eV is obtained as ␤E according to Ngai's coupling model. The microscopic activation energy is related to the association energy of oxygen vacancies.

Complex impedance and electric modulus studies of magnetic ceramic Ni0.27Cu0.10Zn0.63Fe2O4

“…In general, electric modulus corresponds to the relaxation of the electric field in the material when the electric displacement remains constant. The effectiveness of the modulus illustration in the analysis of the relaxation properties has been demonstrated for many polycrystalline ceramics [27][28][29]. Figure 6 shows the frequency dependence of M  at various SM T .…”

Cage decay, near constant loss, and crossover to cooperative ion motion in ionic conductors: Insight from experimental data

“…The existence of NCL in glassy ionic conductors is well known. Evidences for its existence was suggested repeatedly over the span of several decades [1][2][3][4][5][6][7][8][9][10][11][12] and it is now considered to be a universal characteristic of ionic conductors, 13,14 although till now there are only a few investigations of its properties. [11][12][13][14][15][16][17][18][19] This NCL contribution appears at higher frequency than the ion hopping ac conductivity hop Ј ( ).…”

Crossover from ionic hopping to nearly constant loss in the fast ionic conductorLi0.18La0.61TiORivera-Calzada1, Yebra2, Sanz3 et al. 2002Phys. Rev. BSelf Cite393220View full textAdd to dashboardCite

“…͑1͒ originates from a migration of ions by hopping between neighboring potential wells, which eventually gives rise to a dc conductivity at the lowest frequencies. Interestingly, it is usually assumed in the literature 2,[21][22][23][24][25][26] that the Jonscher conductivity and the linear frequency term ͑or NCL͒ are additive contributions, and that the total ac conductivity can be described by the so-called augmented Jonscher form…”