Transport Properties of Ferrous Oxide Fe_1−<i>y</i>O at High Temperature

Abstract

Abstract Electrical conductivity and thermoelectric power of ferrous oxide are measured as a function of temperature (1090 to 1580 K) and oxygen pressure in the whole range of its stability. The results are analysed with reference to the measurements of its deviation from stoichiometry. It is shown that at temperatures exceeding 1070 K the total electrical conductivity of Fe 1− y O is a sum of intrinsic and extrinsic conductivity related to the ionic defect concentration. It is shown that a simple band model is insufficient to describe the electrical properties of Fe 1− y O. A semiconductor–metal transition is revealed in Fe 1− y O. The semiconductor–metal transition corresponds to the stability limits of wustite pseudophases (w 1 , w 2 ). A qualitative model of electronic structure of Fe 1− y O is proposed.