Theoretical analysis of the impedance spectra of electroceramics Part 2: isotropic grain boundaries

Abstract

The grain-size dependence of impedance spectra of electroceramics is simulated, based on a brick layer model with explicit consideration of parallel boundaries. A constant grain interior conductivity is assumed and the grain boundary (gb) conductivity is varied. Parallel and series gb are assumed isotropic, i.e. charge transport along and across gb is supposed identical. Various grain sizes between 500 and 0.5 nm are studied and impedance spectra are shown in complex plane and Bode representations.

Quantification of microstructural features in gadolinia-doped ceria containing co-additives by digital image analysis

“…A demonstration on the role of grain shape on the electrical behavior was reported in the literature. 3 Moreover, it is well known that the choice of the starting powder can have a significant influence on the sinterability and on the microstructure of ceramic systems. In addition, agglomerates are known to impart a dominant influence on the densification behavior of powder compacts [4][5][6][7][8] screening the effect caused by the particle size distribution.…”

Structure and electrical properties of Co0.5CdxFe2.5−xO4 ferrites

“…The grain interior contribution is usually observed at high frequency, whereas the contribution of series g b is observed at lower frequency. The electrical properties of polycrystalline materials are generally determined by this technique with ac frequencies typically in the range between 10 6 and 10 −1 S −1 [11].…”

In situ dilatometric and impedance spectroscopic study of core–shell like structures: insights into the exceptional catalytic activity of nanocrystalline Cu-doped CeO2

“…[57][58][59] In our case, an interfacial layer (copper oxide or metallic copper) is assumed between the CeO 2 grains. s i is the dc conductivity and 3 i the dielectric permittivity of phase i.…”