Application of principal component analysis and Raman spectroscopy in the analysis of polycrystalline BaTiO3 at high pressure

The principal component analysis (PCA) was applied to Raman spectra of polycrystalline BaTiO3 under pressure from atmospheric pressure to ∼6.72 GPa. For the system utilized, PCA was able to distinguish spectral features and to determine the phase transition pressure: tetragonal to cubic at ∼2.0 GPa. The present study demonstrates the potentialities of the application of PCA to the investigation on phase transitions at high pressure by Raman spectroscopy.