Electron spin resonance was used to investigate the diffusion of Fe3+ in rutile. Electron spin resonance absorption intensity was measured for several annealing times and three different temperatures of isothermal annealing: 1273, 1323 and 1373K. The activation energy for diffusion, calculated from the experimental data using a theoretical model based upon Fick’s equation, was found to be EA = 215kJ/mol. This result was consistent with experimental data using the radioactive-tracer sectioning technique and represents an independent measurement of the activation energy for diffusion of trivalent iron in rutile, which was difficult to achieve by other means in this mixed-valence system.

ESR Investigation of Fe3+ Diffusion in Rutile. De Biasi, R.S., Grillo, M.L.N.: Journal of Physics and Chemistry of Solids, 1996, 57[1], 137-8