Phonon density of states of 57-iron and 161-dysprosium in dysprosium-iron by nuclear resonant inelastic x-ray scattering under high pressure

The dual partial phonon density of states (DOS) from two different Mossbauer isotopes (161Dy and 57Fe) in the same material (dyfe3) was successfully measured using the nuclear resonant inelastic x-ray scattering (NRIXS) technique at high pressure. Nuclear inelastic scattering measurements yield an in-depth understanding of the element-specific dynamic properties. The Debye temperatures (thetaD), the Lamb-Mossbauer factor (fLM), and the vibrational contributions to the Helmholtz free energy (Fvib ), specific heat (cV), entropy (Svib) and internal energy (Uvib ) are calculated directly from the phonon density of states.