Concentration dependence of Co diffusion in CoxZr1-x glasses

Using a radiotracer technique in conjunction with ion beam sputtering, we h ave measured the concentration dependence of Co-57 diffusion in CoxZr1-x gl asses for 0.3 less than or equal to x less than or equal to 0.86. The conce ntration dependence at 573 K shows a strong variation over more than three orders of magnitude with a pronounced minimum near x = 0.65. This reflects structural changes, which are consistent with recent molecular dynamics sim ulations and other investigations. The effect of structure on the diffusion mechanism is discussed, in particular in connection with pressure dependen ce and isotope effect measurements.