EXAFS EVIDENCE OF A PHASE-TRANSITION IN ICOSAHEDRAL ALLICU QUASI-CRYSTALS UNDER HIGH-PRESSURE

In situ EXAFS studies, performed at the Cu K absorption edge, are repo rted for icosahedral Al6Li3Cu quasicrystals from ambient pressure up t o 33 cpa. The increase in the average distance of first neighbours aro und Cu atoms above 20 GPa is interpreted as the finger-print of a phas e transition, while the evolution of the disorder parameter could be t he signature of phason disorder.