Impedance spectroscopy of ultrafine-grain SnO2 ceramics with a variable grain sizeстатья
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The impedance spectra of nanocrystalline SnO2 ceramics with an average grain size d ranging from 3 to 43 nm were investigated in the frequency range 1-10(6) Hz at temperatures from 25 to 300 degrees C in a dry oxygen atmosphere. Analysis of the experimental data by the graphoanalytical method made it possible to separate the contributions of grain bulk and grain boundaries to the conductivity. It is shown that the samples investigated can be arbitrarily divided into two groups with respect to the character of their conductivity. For the samples with an average grain size d < 25 nm, the charge transfer processes are almost completely determined by the grain boundaries. In samples with a larger grain size, the contribution of grain bulk to the conductivity is comparable with that of grain boundaries.