“…But further intensive research of this promising material is inhibited by the lack of complete information about the phonon spectrum. It is worth noting that up to now, most experimental studies of the lattice dynamics of ATiO 3 materials with ilmenite structure were performed on the poly-and microcrystalline samples using unpolarized far infrared [20,21,22,23,24,25] and Raman [26,27,28,29,30,31,32,33] spectroscopy.…”