Positive vibrational entropy of chemical ordering in FeV.

Published

Journal Article

Inelastic neutron scattering and nuclear resonant inelastic x-ray scattering were used to measure phonon spectra of FeV as a B2 ordered compound and as a bcc solid solution. The two data sets were combined to give an accurate phonon density of states, and the phonon partial densities of states for V and Fe atoms. Contrary to the behavior of ordering alloys studied to date, the phonons in the B2 ordered phase are softer than in the solid solution. Ordering increases the vibrational entropy by +0.22±0.03 kB/atom, which stabilizes the ordered phase to higher temperatures. First-principles calculations show that the number of electronic states at the Fermi level increases upon ordering, enhancing the screening between ions, and reducing the interatomic force constants. The effect of screening is larger at the V atomic sites than at the Fe atomic sites.

Full Text

Duke Authors

Cited Authors

  • Muñoz, JA; Lucas, MS; Delaire, O; Winterrose, ML; Mauger, L; Li, CW; Sheets, AO; Stone, MB; Abernathy, DL; Xiao, Y; Chow, P; Fultz, B

Published Date

  • September 8, 2011

Published In

Volume / Issue

  • 107 / 11

Start / End Page

  • 115501 -

PubMed ID

  • 22026683

Pubmed Central ID

  • 22026683

Electronic International Standard Serial Number (EISSN)

  • 1079-7114

International Standard Serial Number (ISSN)

  • 0031-9007

Digital Object Identifier (DOI)

  • 10.1103/physrevlett.107.115501

Language

  • eng