Vibrational dynamics of some amorphous and quasicrystalline alloys

Inelastic nuclear resonance scattering has been used to get partial vibrational density of states (PVDOS) of iron in two classes of systems: (i) quasicrystalline Al63.5Cu24Fe12.5, its rhombohedral approximant and Al70Cu20Fe10 crystalline (tetragonal) phase and (ii) amorphous Fe80B20 and its crystalline counterpart. PVDOS in quasicrystalline phase consists of a rather broad maximum at 28 meV with a small hump at 21 meV, and is somewhat similar to that in crystalline Al70Cu20Fe10. Results suggest some similarity in the iron environment in quasicrystalline, approximant and crystalline phases. Amorphous Fe80B20 exhibits an excess density of states as compared to the crystalline phase in the energy range 4–21 meV, which may be attributed to the boson peak.