Crystal structure of dense nanocrystalline BaTiO3 ceramics

The dense nanocrystalline BaTiO3 ceramics with the average grain size of 30 nm was sintered by the pressure assisted method. The Raman spectroscopy and the Rietveld refinement were employed to characterize the structural information of the nanocrystalline BaTiO3 ceramics. The structural parameters and the reliability factors for the nanocrystalline BaTiO3 ceramics were successfully determined by the Rietveld refinement based on the analysis of Raman spectra. A multiphase coexistence of tetragonal and orthorhombic phases was observed in 30 nm BaTiO3 ceramics at room temperature. The phenomenon can be explained by the internal stress.