Determination of Phase Transition by Principal Component Analysis Applied to Raman Spectra of Polycristalline BATIO3 at Low and High Temperature

This work describes the principal component analysis (PCA) applied to Raman spectra of polycrystalline BaTiO3 as a function of temperature. During each experiment the samples was continuously heated and the Raman spectrum was registered every 0.5 °C at a rate of 0.1 °C min 1. This procedure is applied on samples BaTiO3 compact powder to obtain their thermal behavior from -190 °C to 230 °C. The PCA method was able to distinguish spectral features to determine the phase transition temperature and the whole thermal history including the structural phase transition from rhombohedra to orthorhombic at -100 °C, orthorhombic to tetragonal at -5 °C and tetragonal to cubic at 121 °C.