Correlation between β Relaxation and Self-Diffusion of the Smallest Constituting Atoms in Metallic Glasses

In multicomponent metallic glasses, we demonstrate that diffusion and secondary (beta) relaxation are closely related. The diffusion motion of the smallest constituting atoms takes place within the temperature and time regimes where the beta relaxations are activated, and, in particular, the two processes have similar activation energies. We suggest cooperative stringlike atomic motion plays an important role in both processes. This finding provides additional insights into the structural origin of the beta relaxations as well as the mechanisms of diffusions in metallic glasses.