Publication Type
Journal
Journal Name
Physical Review B
Publication Date
Page Number
064405
Volume
85
Issue
6
Abstract
The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO3
were measured for temperatures 200 < T < 750K , using inelastic neutron scattering (INS). Our results
indicate that the magnetic spectrum of BiFeO3 closely resembles that of similar Fe perovskites,
such as LaFeO3, despite the cycloid modulation in BiFeO3. 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 diff raction. These results highlight the
importance of spin-phonon coupling in this material.
