Eur. Phys. J. B 67, 209-212 (2009)
https://doi.org/10.1140/epjb/e2009-00033-7

Possible interplay between a two phonon mode and high energy magnetic excitations in BiFeO₃

¹ Laboratoire Matériaux et Phénomènes Quantiques (UMR 7162 CNRS), Université Paris Diderot-Paris 7, 75205 Paris Cedex 13, France
² Service de Physique de l'État Condensé, DSM/DRECAM/SPEC, CEA Saclay, 91191 Gif-sur-Yvette, France

Corresponding author: ^a maximilien.cazayous@univ-paris-diderot.fr

Received: 3 November 2008
Revised: 12 January 2009
Published online: 29 January 2009

Abstract

We have performed Raman measurements on high energy excitations in BiFeO₃ single crystals as a function of both temperature and laser excitation lines. A strong feature observed at 1250 cm^-1 in the Raman spectra has been previously assigned to two phonon overtone. This peak exhibits an unusual frequency shift with the laser lines and the temperature dependence of its Fano lineshape shows two singularities at 150 K and 200 K which can be related to magnetic excitations. In the same energy range, we have also identified the two-magnon excitation with a temperature dependence very similar to the one measured for the one-magnon modes.