The diffusivity of the Mn2+ ions was measured by using conventional serial sectioning and radio-tracer techniques. The activation energy for diffusion, at temperatures ranging from 249 to 420C, was equal to 1.18eV. The high-temperature activation energy was found to be related to the number of electrons in the d-shell. The migration energy could be quantitatively accounted for in terms of the electronic contribution to the ion energy, in the normal and activated positions, resulting from crystal-field splitting.

A.P.Batra, J.P.Hernandez, L.M.Slifkin: Physical Review Letters, 1976, 36[15], 876-8