Inelastic neutron scattering study of acoustic modes in a monodomain AlCuFe quasicrystal

Abstract

Inelastic neutron scattering results evidenced for the first time that acoustic phonon modes can be observed for a quasicrystal. The triple-axes experiments have been performed on a small monodomain Al63Cu 25Fe12 sample. The obtained TA and LA dispersion curves near to strong Bragg peaks do not show any variation with respect to different Q values. Their slopes are isotropic and do not depend on special symmetry directions; they are comparable to those of corresponding curves for pure aluminium. We have not been able to observe energy gaps in our measurements.