Diffusion in (00▪2)-oriented polycrystalline Co90Fe10/Ru multi-layers was measured and quantified by means of X-ray reflectivity at 450 to 540C. The bulk diffusion could be described by:

D (m2/s) = 6.43 x 10-9 exp[-4.95(eV)/kT]

No grain boundary diffusion was detected in the large-grain structure dominated by high-symmetry grain boundaries within the above temperature interval. It was noted that, for a spin-valve structure that contained Co90Fe10/Ru interfaces, it was clear that – in the absence of grain boundary diffusion and a very high activation energy for bulk diffusion - degradation would first take place at another interface, or via another phenomenon.

Diffusion in Co90Fe10/Ru Multilayers. E.B.Svedberg, K.J.Howard, M.C.Bønsager, B.B.Pant, A.G.Roy, D.E.Laughlin: Journal of Applied Physics, 2003, 94[2], 993-1000

Figure 3

Grain-Boundary Diffusivity of Cu in Electroless Films

(Circles: Co0.9W0.02P0.08, squares: Co0.9P0.1)