Coexistence of Bloch and Néel walls in a collinear antiferromagnet

Abstract

In an antiferromagnet, domain walls separate regions with different orientations of the order parameter. Except for a few specific systems, little is known about the internal structure of these domain walls. In this study, the authors image the domain wall structure of the archetypical antiferromagnet Cr${}_{2}$O${}_{3}$ by means of novel quantum sensing techniques. The results are intriguing, as the twist angles are not arbitrary, but vary between Bloch and N\'eel due to a delicate interplay between residual demagnetization and anisotropy energies.