Pairing and Self-Organization of Vortices and Antivortices in h-YMnO$_{3}$

Fascinating vortices and antivortices with ferroelectric domains were discovered in multiferroic hexagonal YMnO$_{3}$ [1]. Interlocking of ferroelectric and structural antiphase domain walls of h-YMnO$_{3}$ is one of the important ingredients for the topologically-nontrivial domain pattern formation. We have recently investigated the large-scale configuration of vortices and antivortices in h-YMnO$_{3}$ using selective chemical etching. Our results indicate the importance of pairing of vortices and antivortices, and provide valuable insights into understanding the self-organization mechanism of a zoo of vortices and antivortices. Furthermore, we have studied the response of the vortices and antivortices configuration to external stimuli such as external electric fields. \\[4pt] [1] T. Choi et al., Nature Mater. \textbf{9}, 253 (2010).