In situ orientation mapping in hybrid improper ferroelectrics under applied electric field

Hybrid improper ferroelectrics (HIF) are a class of materials where polarisation itself is not the primary order parameter but arises instead from coupling to non-polar distortions (e.g. octahedral rotations). Despite substantial progress over the last years, the nature of polarisation switching mechanisms and domain structure remain elusive. Recently we demonstrated through in situ diffraction that the structural response of a polycrystalline HIF to electric field points to one of the allowed symmetry-lowering switching pathways (X2+) being much softer than the others. The next step in understanding the field-induced switching mechanism is to probe the grain-resolved response by in situ 3DXRD. By highlighting the spatial correlation of switching grains through their characteristic superstructure reflections we will better understand both the relation between crystallographic orientation and field direction and the microstructural origin of the observed structural response.