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Phonons in aluminum at high temperatures studied by inelastic neutron scattering

Kresch, M. and Lucas, M. and Delaire, O. and Lin, J. Y. Y. and Fultz, B. (2008) Phonons in aluminum at high temperatures studied by inelastic neutron scattering. Physical Review B, 77 (2). Art. No. 024301. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:KREprb08

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Abstract

Inelastic neutron scattering measurements on aluminum metal were performed at temperatures of 10, 150, 300, 525, and 775 K using direct-geometry Fermi chopper spectrometers. The temperature dependent phonon density of states (DOS) was determined from the scattering, and was used to fit Born–von Kármán models of lattice dynamics. The shifts in the phonon frequencies with increasing temperature were largely explained by the softening of the longitudinal force constants out to third nearest neighbors. A significant broadening of the phonon spectra at high temperatures was also measured. The phonon DOS was used to determine the vibrational contributions to the entropy of aluminum as a function of temperature. All other contributions to the entropy of aluminum were calculated or assessed, and the total entropy was in excellent agreement with the NIST-JANAF compilation [M. W. Chase, J. Phys. Chem. Ref. Data Monogr. 9, 59 (1998)]. Anharmonic effects were attributed to phonon-phonon interactions. The quasiharmonic approximation was generally successful, but its weaknesses are discussed.


Item Type:Article
ORCID:
AuthorORCID
Lin, J. Y. Y.0000-0001-9233-0100
Fultz, B.0000-0002-6364-8782
Additional Information:© 2008 The American Physical Society. (Received 14 August 2007; published 3 January 2008) We thank L. Jirik, K. Littrell, and A. Kolesnikov for their support during our LRMECS beamtime, and L. Daemen for his support during our Pharos beamtime. We also thank R. Stevens for help with experiments, and M. Winterrose and J. McCorquodale for help with the computational effort. This work has benefited from the use of the Intense Pulsed Neutron Source at Argonne National Laboratory and the Los Alamos Neutron Science Center at Los Alamos National Laboratory. These facilities are funded by the U.S. Department of Energy, under Contracts No. W-31-109-Eng-38 and No. DEAC52-06NA25396, respectively. Finally, this work was supported by the Department of Energy through Basic Energy Sciences Grant No. DE-FG02-03ER46055.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)W-31-109-ENG-38
Department of Energy (DOE)DE-AC52-06NA25396
Department of Energy (DOE)DE-FG02-03ER46055
Subject Keywords:aluminium; anharmonic lattice modes; entropy; neutron diffraction; phonon spectra; phonon-phonon interactions; soft modes
Record Number:CaltechAUTHORS:KREprb08
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:KREprb08
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.77.024301
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9459
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:07 Jan 2008
Last Modified:31 Oct 2017 18:12

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