“Bloch lines” in domain walls of yttrium orthoferrite

Images of Bloch lines and variations of the brightness of the domain wall images were observed by means of a dark field method in thin plates of orthoferrites cut perpendicularly to the optical axis. A connection between the brightness variations and changes in the domain wall inclinations is discussed. The domain wall structure changes with the external inhomogeneous magnetic field and depends on the preceeding domain wall state.