Skip to Main content Skip to Navigation
Journal articles

Phonons in the multiferroic langasite Ba3NbFe3Si2O14 : evidences for symmetry breaking

Abstract : The chiral langasite Ba$_3$NbFe$_3$Si$_2$O$_{14}$ is a multiferroic compound. While its magnetic order below T$_N$=27 K is now well characterised, its polar order is still controversial. We thus looked at the phonon spectrum and its temperature dependence to unravel possible crystal symmetry breaking. We combined optical measurements (both infrared and Raman spectroscopy) with ab initio calculations and show that signatures of a polar state are clearly present in the phonon spectrum even at room temperature. An additional symmetry lowering occurs below 120~K as seen from emergence of softer phonon modes in the THz range. These results confirm the multiferroic nature of this langasite and open new routes to understand the origin of the polar state.
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-01186067
Contributor : Sophie de Brion Connect in order to contact the contributor
Submitted on : Tuesday, August 25, 2015 - 11:33:24 AM
Last modification on : Tuesday, October 19, 2021 - 10:50:41 PM
Long-term archiving on: : Thursday, November 26, 2015 - 1:51:42 PM

Files

Phonons_v4_So.pdf
Files produced by the author(s)

Identifiers

Citation

C. Toulouse, M. Cazayous, Sophie de Brion, Florence Lévy-Bertrand, H. Barkaoui, et al.. Phonons in the multiferroic langasite Ba3NbFe3Si2O14 : evidences for symmetry breaking. Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2015, 92 (10), pp.104302. ⟨10.1103/PhysRevB.92.104302⟩. ⟨hal-01186067⟩

Share

Metrics

Record views

665

Files downloads

1061