Unusual phonon softening in delta-phase plutonium

Creators: McQueeney, R. J.; Lawson, A. C.; Migliori, A.; Kelley, T. M.; Fultz, B.; Ramos, M.; Martinez, B.; Lashley, J. C.; Vogel, S. C.

Abstract

The phonon density of states and adiabatic sound velocities were measured on fcc-stabilized (242)pu(0.95)Al(0.05). The phonon frequencies and sound velocities decrease considerably (soften) with increasing temperature despite negligible thermal expansion. The frequency softening of the transverse branch along the [111] direction is anomalously large (similar to 30%) and is very sensitive to alloy composition. The large magnitude of the phonon softening is not observed in any other fcc metals and may arise from an unusual temperature dependence of the electronic structure in this narrow 5f-band metal.

Additional Information

© 2004 The American Physical Society. Received 11 June 2003; published 7 April 2004. R. J. M. thanks M. Graf, B. Harmon, M. Manley, J. Sarrao, J. Schmalian, S. Shastry, J. L. Smith, C. Stassis, J. D. Thompson, and J. Wills for valuable discussions. This research is sponsored by the United States Department of Energy National Nuclear Security Administration and by the Office of Science DE-FG03-96ER45572. The work has benefited from the use of the Los Alamos Neutron Science Center at Los Alamos National Laboratory. LANSCE is funded by the U.S. Department of Energy under Contract No. W-7405-ENG-36.

Attached Files

Published - MCQprl04.pdf

Files

MCQprl04.pdf

Files (266.0 kB)

Name	Size	Download all
MCQprl04.pdf md5:346ef285f1c4d901720c4a156c794459	266.0 kB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes