KMID : 1059519870310050406
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Journal of the Korean Chemical Society 1987 Volume.31 No. 5 p.406 ~ p.412
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Conduction Band Model of the System ¥á-Fe2O3-CdO at Extrinsic Region
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Kim Keu-Hong
Yun Saeok-Ho Kwon Young-Sik Choi Jae-Shi
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Abstract
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The electrical conductivities of ¥á-Fe2O3 containing 2.5 and 5.0mol% of cadmium were measured from 300 to 900¡É under oxygen pressures of 10-7 to 10-1 atmosphere. Plots of log ¥ò vs. 103/T show the extrinsic conductivity at oxygen pressure higher than 5 ¡¿ 10-2 atm. The transition points appear at about 550¡É and the activation energies are 1.34 eV for the intrinsic region and 0.50 eV for the extrinsic region on 5mol% Cd-doped ¥á-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 ¥á-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.
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KEYWORD
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