Raman scattering study of the ferroelectric phase transition in BaTiO

Tsukada, Shinya*; Fujii, Yasuhiro*; Yoneda, Yasuhiro   ; Moriwake, Hiroki*; Konishi, Ayako*; Akishige, Yukikuni*

Uniaxial ferroelectric BaTiO with a Curie temperature of 743 K was investigated to clarify its paraelectric-ferroelectric phase transition behavior. The mechanism is discussed on the basis of the structure from short to long ranges determined by synchrotron X-ray diffraction and the lattice dynamics probed by Raman spectroscopy. Using a combination of experimental results and first-principles calculations, we explain the phase transition. Ti vibration of TiO octahedral units is frozen in the ferroelectric phase and the space group changes from nonpolar to polar .