Atomic dynamics of an Al0.62Cu0.255Fe0.125 icosahedral quasicrystal

The atomic dynamics of an Al_0.62Cu_0.255Fe_0.125 icosahedral quasicrystal is investigated using inelastic neutron scattering (the isotopic contrast method). The partial vibrational spectra of copper, iron, and aluminum atoms in the icosahedral quasicrystal and the total spectrum of thermal vibrations of the compound are directly reconstructed from the experimental data for the first time. It is found that the vibrational energies of copper and iron atoms fall in relatively narrow ranges near 16 and 30 meV, respectively, whereas the vibrational energies of aluminum atoms lie in a wide range (up to 60 meV).