Fig. 5: Polygonal texture of vortices in an N_F film.

a Polarizing microscopy texture. The film thickness increases from the center (h ≈ 5 μm) to the periphery (h ≈ 10 μm). Two neighboring +1 vortices of the same circulation direction are separated by H- and T-walls, while two domains of an opposite circulation show a relatively smooth transition with splay regions (shown by yellow arrows). White and black circular arrows depict polarization circulations. b Scheme of polarization pattern in domains 1-4 in part (a). Red arrows of polarization exhibit splay and produce bound charges. Thick solid lines are H-wall, thin solid lines are T-walls; dashed lines show transitions between vortices of opposite circulation at which splay produces space charges.