Total interference between nuclear and magnetovibrational one-phonon scattering cross sections

• Published in: Journal of physics. Conference series Vol. 1316; no. 1; pp. 12018 - 12025
• Main Authors: Raymond, S., Biniskos, N., Schmalzl, K., Persson, J., Brückel, T.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.2019; IOP Science
• Subjects: Brillouin zones; Channels; Condensed Matter; Ferromagnetism; Inelastic scattering; Interference; Low temperature; Materials Science; Neutron scattering; Neutrons; Phonons; Physics; Polarization (spin alignment); Scattering cross sections; Strongly Correlated Electrons
• ISSN: 1742-6588; 1742-6596; 1742-6596; 1742-6588
• DOI: 10.1088/1742-6596/1316/1/012018

A full phonon intensity cancellation is reported in a longitudinal polarized inelastic neutron scattering experiment performed on the magnetocaloric compound MnFe4Si3, a ferromagnet with TCurie ≈ 305 K. The TA[100] phonon polarized along the c-axis measured from the Brillouin zone center G=(0, 0, 2) is observed only in one ( σ z + + ) of the two non-spin-flip polarization channels and is absent in the other one ( σ z − − ) at low temperatures. This effect disappears at higher temperatures, in the vicinity of TCurie, where the phonon is measured in both channels with nonetheless marked different intensities. The effect is understood as originating from nuclear-magnetic interference between the nuclear one-phonon and the magnetovibrational one-phonon scattering cross-sections. The total cancellation reported is accidental, i.e. does not correspond to a systematic effect, as established by measurements in different Brillouin zones.