Effect of growing barium ferrite phases on the electrical conduction in Fe2O3/BaCo3 composite

The effect of heat treatment on the temperature dependence of electrical conduction for a mixture of Fe2O3 and BaCO3 with 1:1 mole ratio has been studied between room temperature and 573 K. The results suggest protonic conduction at a relatively low temperature range, whereas small polaron jumping between Fe2+ and Fe3+ dominates at a relatively high temperature range. The electrical conduction at high fields exhibits a quadratic dependence of current on the applied potential which predicts the formation of space charge. The mobility and concentration of charge carriers are estimated and discussed for untreated and heat treated Fe2O3/BaCO3 composites. (C) 1998 Elsevier Science S.A.