It was found that the data for 60Co diffusion could be described by:

ferromagnetic α-Fe:     D (cm2/s) = 7.19 x 100 exp[-62.2(kcal/mol)/RT]

paramagnetic α-Fe:     D (cm2/s) = 6.38 x 100 exp[-61.4(kcal/mol)/RT]

δ-Fe:     D (cm2/s) = 6.38 x 100 exp[-61.4(kcal/mol)/RT]

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