Significant phonon assignments in multiferroic BiFeO3 single crystal

Abstract

In the present work, the technique of Back Scattering Micro-Raman was employed at low and room temperatures in order to examine all the possible phonon vibration modes present in a crystal of BiFeO3(BFO). The observation & identification of all E (TO), E (LO), A1 (TO), and A1 (LO) normal modes was sucessfully accomplished. The low temperature Raman spectroscopy measurements showed two one-magnon branches, σ-magnon at 20.06 cm−1 and γ-magnon at 26.93 cm−1. The spectral characteristics of the three A1 (LO) modes were observed at roughly 176.63 cm−1, 225.93 cm−1 and 505.53 cm−1, exhibiting low intensity longitudinal optical modes. The observed peaks at 145.34 cm−1, 223.92 cm−1, 292.54 cm−1, and 552.18 cm−1 were identified and categorized as A1 (TO) modes. E (TO) peaks were observed at 73.30 cm-1, 131.94 cm-1, 239.35 cm-1, 265.04 cm-1, 278.45 cm-1, 349.95 cm-1, 374.69 cm-1, 441.04 cm-1, 522.99 cm-1. In addition, E(LO) peaks were observed at 80.76 cm-1, 175.03 cm-1, 241.59 cm-1, 275.42 cm-1, 346.92 cm-1, 371.34 cm-1, 419.38 cm-1, and 469.65 cm-1.