DEFECTS AND CATION DIFFUSION IN MAGNETITE (IV) - NONSTOICHIOMETRY AND POINT-DEFECT STRUCTURE OF MAGNETITE FE-3-DELTA-O-4

Nonstoichiometry and point defect structure of magnetite have been studied experimentally by thermogravimetry covering the stability range of magnetite between 900 and 1400 degree C. A cation deficit is observed at high and a cation excess at low oxygen activities corresponding to cation vacancies and iron interstitials as the predominant point defects, respectively. An overexponential temperature dependence occurs for the defect concentrations in stoichiometric magnetite.