Phonon density of states of nanocrystalline Fe prepared by high-energy ball milling
- California Institute of Technology, mail 138-78, Pasadena, California 91125 (United States)
- Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
We performed inelastic neutron scattering measurements on nanophase Fe powders prepared by high-energy ball milling. Neutron energy loss spectra were measured for two states of the material: (1) as milled, when the material had a characteristic nanocrystallite size of 12 nm; and (2) annealed, when the material had a characteristic crystallite size of 28 nm. The longitudinal peak in the phonon density of states (DOS) of the nanophase Fe was broadened, compared to that of the annealed material. We attribute this broadening to short phonon lifetimes in nanocrystals. The nanophase material also showed an enhanced density of states at low energies below 15 meV, which may indicate the presence of intercrystallite vibrations. These differences in phonon DOS should have only a small effect on the difference in vibrational entropy of nanocrystalline and larger-grained Fe. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Oak Ridge National Laboratory
- DOE Contract Number:
- AC05-84OR21400; FG03-86ER45270
- OSTI ID:
- 284253
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Microstructural characterization of amorphous and nanocrystalline boron nitride prepared by high-energy ball milling
Vibrational Properties of Nanograins and Interfaces in Nanocrystalline Materials