Defects and Cation Diffusion in Magnetite (V): Electrical Conduction, Cation Distribution and Point Defects in Fe3‐δO4

Electrical conductivity in magnetite has been studied experimentally as a function of temperature and oxygen activity between 560 and 1400°C. The results indicate that above TC (=575°C) an octahedral site small polaron mechanism is dominant over the entire temperature range (Ea = 0.1136 eV). By comparing data on electrical conductivity and thermoelectric power, a second (small polaron) mechanism (Ea = 0.714 eV) is detected at elevated temperatures. Additionally, equilibrium constants for the cation vacancy formation are derived from fitting the conductivity isotherms as a function of oxygen activity. These agree well with values determined thermogravimetrically.