Diffusion in Cobalt-Nickel Alloys

The self-diffusivities of Co60 and Ni63 in cobalt-nickel solid solutions exhibit a greater activation energy below the Curie temperature (Tc) than above. Values of ΔQ=Q (ferromagnetic) —Q (paramagnetic) are approximately equal to RTc. This is interpreted to indicate that the increment in activation energy arises from an increase in the formation energy of a vacancy in the ferromagnetic lattice, with the additional binding energy arising from the interaction of a spin with the Weiss field.