Inelastic neutron scattering, phonon softening, and the phase transition in sodi

2019-06-05 08:17:22

point dependence scattering phonon inelastic

责任者: Harris, M.J.;Hagen, M.E.;Dove, M.T.;Swainson, I.P. 单位: Rutherford Appleton Lab, Oxfordshire, Engl 来源出处: Journal of Physics Condensed Matter,1998,10(30):6851-6861 摘要: Neutron scattering measurements have been performed on sodium nitrate (NaNO3) at temperatures between 16 and 553 K, using both time-of-flight and triple-axis spectrometers, focusing on the phonon modes with wavevectors between the Brillouin zone centre and the F zone boundary point. At the F point there is a significant softening in energy of a transverse acoustic phonon branch on heating. Unlike the case of the related material calcite, there is no continuum of inelastic scattering localized in reciprocal space about the F point, and with a strong temperature dependence. Instead we find a component of inelastic scattering that is broad in both energy and wavevector, and with only a weak dependence on temperature. 关键词: ;