; Zhu, K.
; Liu, Y. L.] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
; [Bai, L. G.
; Jiang, S.
; Liu, J.] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; [Chen, J.
; Xing, X. R.] Univ Sci & Technol Beijing, Dept Phys Chem, Beijing 100083, Peoples R China
We have reported a Raman scattering investigation of bismuth ferrite (BiFeO3) under high pressure up to 50 GPa. Distinct changes in the Raman spectra show evidence for three pressure-induced structural transitions. The abrupt frequency redshifts of the Raman modes near 300 cm(-1) at around 3 GPa are attributed to the modulation of the FeO6 octahedral tilts. The disappearance of the modes below 250 cm(-1) at 8.6 GPa, together with the enhancement of the two modes in the range of 300-400 cm(-1), indicate the phase transition from the rhombohedral to orthorhombic symmetry. Afterward, the E-3 and E-4 modes disappear at 44.6 GPa, pointing to the occurrence of the orthorhombic-cubic phase transition, which is consistent with the previous postulate that an orthorhombic-cubic transition takes place across the metal-insulator transition at high pressures.