Aluminum self-diffusion in a monodomain icosahedral quasicrystal ${\mathrm{Al}}_{72.4}{\mathrm{Pd}}_{20.5}{\mathrm{Mn}}_{7.1}$ has been studied at temperatures between 4 and 400 K by ${}^{27}\mathrm{Al}$ NMR measurements of the decay of transverse nuclear spin magnetization in a spatially inhomogeneous electric field gradient. Temperature dependence of the renormalized diffusion constant can be explained in the framework of the Kalugin-Katz phason-assisted diffusion model where the atomic jumps occur as a result of the presence of matching-rules violation defects. The observed self-diffusion process resembles a percolation transition with the percolation threshold at 72 K.

• Received 7 May 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.572