Phonons in Nanocrystalline {sup 57}Fe

Journal Article · Fri Aug 01 00:00:00 EDT 1997 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.79.937· OSTI ID:528132

Fultz, B; Ahn, C C ^[1]; Alp, E E; Sturhahn, W; Toellner, T S ^[2]

---

1. Division of Engineering and Applied Science, 138-78, California Institute of Technology, Pasadena, California 91125 (United States)
2. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear {gamma} -ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Q{sub u} , averaging about 5, but the longitudinal modes may have been broadened most. The nanocrystalline Fe also shows an enhancement in its phonon DOS at energies below 15 meV. The difference in vibrational entropy of the bulk and nanocrystalline Fe was small, owing to competing changes in the nanocrystalline phonon DOS at low and high energies. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 528132
• Journal Information: Physical Review Letters, Vol. 79, Issue 5; Other Information: PBD: Aug 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
IRON 57
PHONONS
INELASTIC SCATTERING
GAMMA RADIATION
ENERGY-LEVEL DENSITY
VIBRATIONAL STATES
RESONANCE SCATTERING