High pressure Raman studies of dense nanocrystalline BaTiO3 ceramic

High pressure Raman spectra have been measured on 20 nm BaTiO3 ceramic from atmospheric pressure to 36.7 GPa. It was found that most of tetragonal phase has transformed to orthorhombic phase at about 10.9 GPa, and a new phase appeared at about 19.8 GPa. Raman modes still persisted up to 36.7 GPa. The phase transition was reversible.