Evidence of Highly Collective Co Diffusion in the Whole Stability Range of Co-Zr Glasses

Abstract

Using a radiotracer technique, we have measured the isotope effect E = dln(D)/dln(m(1/2)) of Co diffusion in CoxZr1-x glasses for 0. 31</=x</=0.86. E is close to zero (E = 0+/-0.1) in the whole range, covering 3 orders of magnitude in the diffusivity, despite the existence of large activation volumes. These results strongly suggest a highly collective diffusion mechanism to be a quite general phenomenon in metallic glasses and point to diffusion via delocalized thermal effects at certain compositions.