Imaging topological defects in a non-collinear antiferromagnet

Abstract

We report on the formation of topological defects emerging from the cycloidal antiferromagnetic order at the surface of bulk BiFeO${}_3$ crystals. Combining reciprocal and real-space magnetic imaging techniques, we first observe, in a single ferroelectric domain, the coexistence of antiferromagnetic domains in which the antiferromagnetic cycloid propagates along different wavevectors. We then show that the direction of these wavevectors is not strictly locked to the preferred crystallographic axes as continuous rotations bridge different wavevectors. At the junctions between the magnetic domains, we observe topological line defects identical to those found in a broad variety of lamellar physical systems with rotational symmetries. Our work establishes the presence of these magnetic objects at room temperature in the multiferroic antiferromagnet BiFeO${}_3$, offering new possibilities for their use in spintronics.

7 pages, 4 figures, supplemental material as ancillary file

References in corpus (5)

• Spin current and magneto-electric effect in non-collinear magnets
• Room temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals
• Electric-field-induced spin-flop in BiFeO3 single crystals at room-temperature
• Real-space imaging of non-collinear antiferromagnetic order with a single spin magnetometer
• Strain and Magnetic Field Induced Spin-Structure Transitions in Multiferroic BiFeO3