ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 31, Number 5
JKCSEZ 31(5)
October 20, 1987 

The electrical conductivities of α-Fe2O3 containing 2.5 and 5.0mol% of cadmium were measured from 300 to 900℃ under oxygen pressures of 10-7 to 10-1 atmosphere. Plots of log σ vs. 103/T show the extrinsic conductivity at oxygen pressure higher than 5 × 10-2 atm. The transition points appear at about 550℃ and the activation energies are 1.34 eV for the intrinsic region and 0.50 eV for the extrinsic region on 5mol% Cd-doped α-Fe2O3. The extrinsic conductivity disappears at oxygen partial pressures lower than 5 × 10-2 atm, and the intrinsic conductivity predominates. The electrical conductivities decrease with increasing mol% of cadmium doped. The predominant defect of α-Fe2O3 doped with Cd is believed to be Fe2+ interstitial for the intrinsic, however, oxygen vacancy predominates for the extrinsic region. The electrical conduction mechanisms are proposed and the conduction band model is suggested for the extrinsic region.