Vibrational density of states of nanocrystalline Ni3Fe

We measured inelastic neutron scattering spectra for two states of Ni3Fe: firstly as milled, when the material had a characteristic nanocrystallite size of 9 nm; secondly annealed, when the material had a characteristic crystallite size of 30 nm. The nanocrystalline material showed an enhancement by a factor of two in it density of states (DOS) at energies below 15 meV, and some broadening of its longitudinal peak at 33 meV The differences between the vibrational DOSs of the nanocrystalline and annealed materials provide a difference in vibrational entropy of 0.18k(B) atom(-1) at high temperatures.