Detailed Evolution of the Ferroelectric Phase Transition in BaTiO₃

Abstract

Nearly quasi-static temperature change by our MKS-cell has enabled to find the onset of the ferroelectric transition concerning a cubed BaTiO₃ single crystal. It proceeds by two steps within 1 mK. The first step to the tetragonal structure has no Ti atoms displacement. The second step accompanies a displacement current in one direction and vanishing of the tetragonal distortion. The experiments suggest that a domain formation model is valid: parallel monoclinic thin domains align interstitially with the tetragonal domains like walls. The displacement current corresponds to charges one order smaller than the one obtained from the hysteresis curve by Merz.

Keywords:

• BaTiO₃ single crystals
• simultaneous measurements
• ferroelectric transition
• micro-Raman mapping
• domain formation model
• occurrence of ferroelectricity

Acknowledgments

A. K. is very grateful to Dr. Annette Bussmann-Holder of Max Planck Institute for her hearty encouragement. He also acknowledges Professor Amar Bhalla of The University of Texas at San Antonio for his precious comments to the present paper.