Switching behaviour in displacive and rotational ionic molecular ferroelectrics

Ionic molecular ferroelectrics are an emerging class of ferroelectrics made of molecular constituents. The ferroelectricity in these materials can arise due to ionic displacement, molecular dipole rotation, or a combination of both. The role of the polarization mechanism on the ferroelectric and piezoelectric properties is unclear. We propose an in situ powder diffraction study of these materials under electric fields to show a link between the polarization mechanisms and the domain switching behaviour. At high fields the domain nucleation and growth process will be captured by the changing diffraction pattern. While the low field measurements will show lattice strain and small domain fraction changes as the piezoelectric effect and domain wall mobility influence the crystal structure. There are no such studies of these materials in the literature and the information this will provide will be the first step towards domain engineering of functional properties of these materials.