It was found that the data for 55Fe and 59Fe diffusion could be described by:

ferromagnetic α-Fe:     D (cm2/s) = 2.75 x 101 exp[-60.7(kcal/mol)/RT]

paramagnetic α-Fe:     D (cm2/s) = 2.01 x 100 exp[-57.5(kcal/mol)/RT]

δ-Fe:     D (cm2/s) = 2.01 x 100 exp[-57.5(kcal/mol)/RT]

D.W.James, G.M.Leak: Philosophical Magazine, 1966, 14, 701-13