Abstract
Plastic crystals are a class of compounds composed of molecules with globular structures. Plastic crystals exhibit several unique features arising from isotropic rotator motion of their constituent molecules. We have discovered that certain plastic crystals based on ionic molecules undergo phase transitions to ferroelectric phases upon cooling. These crystals, i.e., plastic/ferroelectric crystals display several unique features that differ from conventional molecular ferroelectric crystals. In particular, the materials have achieved ferroelectric performance for the first time as bulk polycrystals composed of small molecules. In this article, we outline the development and distinctive features of plastic/ferroelectric crystals, focusing on their ferroelectricity and related properties in bulk polycrystalline forms.
https://ror.org/02e16g702 
