The tracer diffusion coefficient of 99Mo in α-Fe was determined, between 833 and 1163K, by using a serial sputter-microsectioning technique. The temperature dependence of the diffusion coefficient over the whole temperature range across the Curie temperature could be described by:

D (m2/s) = 1.48 x 10-2exp[-282.6(kJ/mol)(1 + 0.074s2)/RT]

where s was the ratio of the spontaneous magnetization, at a given temperature, to that at 0K. The factor 0.074 in the above equation was smaller than the 0.156 for self-diffusion in α-Fe; thus showing that the effect of the magnetic transformation upon the diffusion of Mo in α-Fe was less than that upon self-diffusion, as expected from the negative magnetic moment of Mo in the lattice of ferromagnetic Fe.

H.Nitta, T.Yamamoto, R.Kanno, K.Takasawa, T.Iida, Y.Yamazaki, S.Ogu, Y.Iijima: Acta Materialia, 2002, 50[16], 4117-25