The Mössbauer spectra of magnetite were measured at temperatures of up to 1400C, as a function of O partial pressure. The experimental in situ spectra were affected by cation diffusion processes. The spectra were deconvoluted into contributions from Fe ions on the tetrahedral and octahedral sites of the spinel structure. On the basis of the observed isothermal O partial pressure dependences of the spectral line-shapes, it was concluded that the cationic dynamics at high O partial pressures were dominated by vacancy diffusion on the octahedral sub-lattice. At low O partial pressures, interstitialcy processes which involved tetrahedrally coordinated Fe ions predominated. Exchange processes played only a minor role.

K.D.Becker, V.Von Wurmb, F.J.Litterst: Journal of the Physics and Chemistry of Solids, 1993, 54[8], 923-35