Raman Study of the Relationship between Room‐Temperature Tetragonality and the Curie Point of Barium Titanate

Abstract

Variable‐temperature Raman spectroscopy showed that, in progressively finer BaTiO 3 powders, the Curie point increased as the room temperature tetragonality decreased. The influence of crystallite size distribution on the range of tetragonalities present in a powder was clearly evident in both phase transitions, as observed by Raman spectroscopy and room‐temperature X‐ray diffraction patterns. Titanium K ‐edge X‐ray absorption spectroscopy could not distinguish between the cubic and tetragonal structures of BaTiO 3 , at 300°C and room temperature, respectively.