3 50 150 250 350 450 0 2 4 6 8 10 12 6 8 10 12 14 16 18 20 22 Frequency variation (cm -1 ) Temperature ($^{o}$C)  Peak 1  Peak 3 T$_{N}$  Peak 2 T$_{N (onset)}$ (c) 50 150 250 350 450 10 20 30 40 50 60 70 T$_{N}$ T$_{N (onset)}$ FWHM (cm -1 ) Temperature ($^{o}$C)  Peak 1  Peak 2  Peak 3 (d) FIG. 1: Temperature dependent Raman spectra of (001)BFO film on SRO/STO from 22-400 ◦ C (a) and 550-1000 ◦ C (b). The graphs in (b) were adapted from our earlier work [15]. The beginning of the dashed arrows pointing up in (b) shows the beginning of the new phase. The existence of phonons in γ -phase in (b) are marked with the solid arrows pointing down. The α -phase extends up to 820 ◦ C; (c) and (d) temperature dependence (RT-500 ◦ C) of phonon frequencies variation and FWHM for 72 (peak 1), 140 (peak 2), and 171(peak 3) cm − $^{1}$, respectively. ruled out. However, the Raman frequencies before and after thermal cycling remain unchanged makes this un- likely. This fact favors films over bulk or powder samples for very high temperature studies in the future. Reach- ing the tetragonal and cubic phases extrapolated from the powder study of Arnold et al. [2] does not seem im- possible with thin films. There are discrepancies in the literature regarding both the crystal structure of (001) BFO thin films e.g. with several reports claiming tetragonal [6, 28], rhombohe- dral [29, 30], and monoclinic [31, 32] structure, and its phonons. Of particular interest regarding phonon- magnon coupling in BFO was the report [24] of a very B. Phonon anomalies near T N :