ATOMIC MOTION IN QUASI-CRYSTALLINE AL70RE8.6PD21.4 - A 2-DIMENSIONAL EXCHANGE NMR-STUDY

Al-27 2D exchange NMR experiments on an icosahedral Al70Re8.6Pd21.4 qu asicrystal have detected slow atomic motions in the sub-kHz range at t emperatures between 0.16 and 130 K. The observed motion is limited in space and can be associated with local phason fluctuations at very low energies, involving quantum tunneling at very low temperatures. It ma y thus be regarded as an atomic motion acting as a precursor to bulk s elf-diffusion. [S0031-9007(98)07456-0].