Microdomains observed at the ferroelectric/paraelectric phase transition of barium titanate

Abstract

The physical properties of barium titanate have been thoroughly studied because of fundamental interest in its singular ferroelectric properties and the wide variety of applications¹. Inelastic neutron and X-ray diffraction studies suggest that the atomic mechanism for the phase transition from the paraelectric (cubic) to ferroelectric (tetragonal) phases lies somewhere between the extremes of ‘displacive’ and ‘order–disorder’ models^1,2. Analysis of the ‘central-peak’ phenomena^2,3 has led to microdomain models, while molecular dynamic computer studies for ferrodistortive and anti-ferrodistortive phase transitions predict travelling clusters of locally-ordered regions, with slowing-down and increasing cluster size close to the critical temperature⁴. Direct evidence for the occurrence of microdomains has been obtained by in situ electron microscopy of the transition.