Phonon and Magnon Excitations in Raman Spectra of an Epitaxial Bismuth Ferrite Film

G. Khabiri , A. S. Anokhin , A. G. Razumnaya , Yu. I. Yuzyuk (1) , I. Gueye , B. Carcan , Houssny Bouyanfif (2) , Jérôme Wolfman (3) , Cecile Autret (3) , Mimoun El Marssi (2)

1 SFEDU - Southern Federal University [Rostov-on-Don]
2 LPMC - Laboratoire de Physique de la Matière Condensée - UR UPJV 2081
3 GREMAN - UMR 7347 - GREMAN (matériaux, microélectronique, acoustique et nanotechnologies)

An epitaxial film of bismuth ferrite BiFeO3 on a MgO(001) single crystal substrate has been pre pared by pulsed laser deposition using SrTiO3 and SrRuO3 buffer layers. At room temperature, the polariza tion characteristics of the Raman spectra of the BiFeO3 film under study suggest a monoclinic symmetry. The high temperature (295\textendash1100 K) investigations of the Raman spectra have been performed in the frequency range 20 cm\textendash1 < ν < 1600 cm\textendash1. Particular attention has been paid to the high frequency region with a band observed at 610 cm\textendash1, which corresponds to the maximum density of states of the magnon branch at the Bril louin zone boundary, and an intense band in the second order Raman spectra with the maximum at ~1250 cm\textendash1, which corresponds to the density of states of two magnon excitations. It has been found that the inten sity of the band at ~1250 cm\textendash1 decreases linearly with an increase in the temperature and, above 650 K, this band is absent. The extrapolation of the temperature dependence of the integrated intensity of the band at 1250 cm\textendash1 suggests that this film undergoes an antiferromagnetic phase transition at a temperature of ~670 K.

Domaines: Matériaux

G. Khabiri, A. S. Anokhin, A. G. Razumnaya, Yu. I. Yuzyuk, I. Gueye, et al.. Phonon and Magnon Excitations in Raman Spectra of an Epitaxial Bismuth Ferrite Film. Physics of the Solid State, 2014, 56 (12), pp.2507--2513. ⟨10.1134/S1063783414120154⟩. ⟨hal-01757213⟩