content_image/378750.jpg
<img src='content_image/378750.jpg'>

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 : 

