Pressure dependence and isotope effect of self-diffusion in a metallic glass

The pressure dependence and isotope effect of cobalt diffusion have been measured in amorphous Co76.7{Fe}₂Nb14.3{B}₇$ and in fcc Co. Within experimental accuracy no pressure dependence and an isotope effect E=(${D}_{{{α}}}$/${D}_{{{β}}}$-1)/[(${m}_{{{β}}}$/${m}_{{{α}}})1/2-1]=0.1 were found in Co76.7{Fe}₂Nb14.3{B}₇$. These results show that diffusion in the metallic glass is not mediated through quasivacancies in thermal equilibrium similar to crystalline Co. Diffusion rather occurs via a direct mechanism involving about ten atomic masses.