X-ray diffraction from the ferroelectric fluctuation and domain walls of barium titanate

Yoneda, Yasuhiro   ; Komura, Yoshiki*; Suzuki, Yoshio*

A careful observation on X-ray diffraction in the ferroelectric crystals such as BaTiO reveals that a new physical picture of the ferroelectric transition in these crystals may rather be regarded as an order-disorder transition. A strong local order in the disordered phase is a characteristic feature. The model gives natural interpretation of the occurrence of a micro cluster phase in the phase transition to explain the existence of the central peak. We also observed the micro cluster phase just behind the phase transition temperature in the tetragonal phase.