Reassessment of the effect of space charge potential on the electrical conductivity of polycrystalline ceramics.

The calculation of space charge potential, the difference of the activation energy of grain boundary and grain, and the ratio of conductivity of grain boundary and grain at different temperatures of the polycrystalline ceramics have been reappraised in the present model, in which charge carriers hopping through bulk and grain boundary barriers with different mobility are taken into account. It is evidenced that the present model is valid and more precise than previous models, and thus, it is concluded that the assumption that the mobility of charge carriers hopping through bulk and grain boundary barrier is the same made by the previous studies is unsuitable. [ABSTRACT FROM AUTHOR]