Residual mechanical stresses in pressure treated BaTiO3 powder

Here we present Raman spectroscopy approach to monitor the spatial distribution and the magnitude of the residual mechanical stresses in ceramic after non-hydrostatic pressure treatments. The residual pressure can be found from the E-phonon line shift (∼307 cm⁻¹) in the Raman spectra. The relationship between the non-hydrostatic pressure (up to 11 GPa) and the shift of this line has been established. It is demonstrated that the change in the Raman line position (1332 cm⁻¹) of the diamond anvil can be used for monitoring of applied non-hydrostatic pressures. A linear dependence of residual mechanical stresses on the applied pressures is found. Micro-Raman spectroscopy shows that the residual mechanical stresses are distributed fairly uniformly in the studied BaTiO₃ samples at the micron scale. In the future, the proposed Raman technique can be used for monitoring the quality of produced BaTiO₃ ceramics.