Phonon dispersion in Co0.92Fe0.08

The dispersion relation for phonons propagating along the [00ζ], [ζζ0], and [ζζζ] directions in face-centred-cubic Co0.92Fe0.08 at T = 296 K has been determined by means of neutron inelastic scattering. The results have been analysed to obtain atomic force constants, the frequency distribution function, and the temperature dependence of the Debye characteristic temperature and the mean square displacement of the atoms. On average, the frequencies for Co0.92Fe0.08 scale approximately as expected with those for Ni and Cu but there are definite wave-vector-dependent variations in the scaling which presumably reflect the different electronic structures of the three materials.