Hi Yagna, BiFeO3 material is Perovskite type of structure : type 'A' atom sits at cube corner positions (0, 0, 0), type 'B' atom sits at body centre position (1/2, 1/2, 1/2) and oxygen atoms sit at face centred positions (1/2, 1/2, 0). So to know the bond formation of Bi-O-Fe and others (O-Fe-O and Bi-O etc), you can see or observe the peaks appear in the region of finger-print (below 700 cm-1). It is better to compare your vibration peaks with that of reference data ( FTIR of Fe2O3 ,  Fe3O4 and Bi-oxides). You will imply whether there is a difference of each bond (your sample and a pure oxides of both iron and bismuth metals.

Hopefully this information will be useful.

Rudy Situmeang

Thank  you very much sir Rafael Schiwan