Making and manipulating ferroelectric vortices, a TEM perspective of nanoscale flux closure in dielectrically confined PbTiO₃ films

A prominent disparity between the two ferroic siblings of ferromagnetism and ferroelectricity is the exciting complex topologies appearing in the spin distributions of former while the electric dipole textures of the latter flag behind. By engineering the scale and field energy minimization pressures driving flux closure formation we realize in SrTiO₃ encapsulated ferroelectric PbTiO₃ thin films the formation of nanoscale ferroelectric vortices. With (S)TEM we characterize the structure of these ~5nm vortices down to atomic scales and study the transition from long-range vortex arrays to in-plane a-domains with decreasing superlattice period, including a mixed structure regime and extrinsic formation of vortices in thicknesses below the vortex-stability limit. Using in-situ applied electric bias we observe the dynamic field-response including the creation, deformation, motion, and erasure of these ferroelectric vortices.