Anharmonic phonons and magnons in BiFeO 3

Journal Article (Journal Article)

The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO 3 were measured for temperatures 200≤T≤750K, using inelastic neutron scattering (INS). Our results indicate that the magnetic spectrum of BiFeO 3 closely resembles that of similar Fe perovskites, such as LaFeO 3, despite the cycloid modulation in BiFeO 3. We do not find any evidence for a spin gap. A strong T dependence of the phonon DOS was found, with a marked broadening of the whole spectrum, providing evidence of strong anharmonicity. This anharmonicity is corroborated by large-amplitude motions of Bi and O ions observed with neutron diffraction. A clear anomaly is seen in the T dependence of Bi-dominated modes across the Néel transition. These results highlight the importance of spin-phonon coupling in this material. © 2012 American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Delaire, O; Stone, MB; Ma, J; Huq, A; Gout, D; Brown, C; Wang, KF; Ren, ZF

Published Date

  • February 13, 2012

Published In

Volume / Issue

  • 85 / 6

Electronic International Standard Serial Number (EISSN)

  • 1550-235X

International Standard Serial Number (ISSN)

  • 1098-0121

Digital Object Identifier (DOI)

  • 10.1103/PhysRevB.85.064405

Citation Source

  • Scopus