Measurements were made of the time-dependence and isotope effect of Co diffusion in thin (1μm) amorphous films during structural relaxation. Radiotracer techniques, together with serial sectioning and ion-beam sputtering, were used. A threefold decrease in the diffusivity was found during structural relaxation at 573K, but no change in the isotope effect was observed. A small isotope effect (0.002) in the relaxed and as-quenched states strongly suggested the operation of collective hopping diffusion mechanisms in both the relaxed and as-quenched states. The results were in accord with results on 1μm-thick amorphous Co51Zr49 films. It was concluded that the absence of any geometrical effect ruled out the annihilation of quenched-in free volume at the outer surfaces of thin Co-Zr glasses.

Does the Diffusion Mechanism in Thin Amorphous Co81Zr19 Films Change during Structural Relaxation? A.Heesemann, K.Rätzke, V.Zöllmer, F.Faupel: New Journal of Physics, 2001, 3, 6