Magnetic stripes and skyrmions with helicity reversals
Top Cited Papers
- 21 May 2012
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 109 (23), 8856-8860
- https://doi.org/10.1073/pnas.1118496109
Abstract
It was recently realized that topological spin textures do not merely have mathematical beauty but can also give rise to unique functionalities of magnetic materials. An example is the skyrmion—a nano-sized bundle of noncoplanar spins—that by virtue of its nontrivial topology acts as a flux of magnetic field on spin-polarized electrons. Lorentz transmission electron microscopy recently emerged as a powerful tool for direct visualization of skyrmions in noncentrosymmetric helimagnets. Topologically, skyrmions are equivalent to magnetic bubbles (cylindrical domains) in ferromagnetic thin films, which were extensively explored in the 1970s for data storage applications. In this study we use Lorentz microscopy to image magnetic domain patterns in the prototypical magnetic oxide–M-type hexaferrite with a hint of scandium. Surprisingly, we find that the magnetic bubbles and stripes in the hexaferrite have a much more complex structure than the skyrmions and spirals in helimagnets, which we associate with the new degree of freedom—helicity (or vector spin chirality) describing the direction of spin rotation across the domain walls. We observe numerous random reversals of helicity in the stripe domain state. Random helicity of cylindrical domain walls coexists with the positional order of magnetic bubbles in a triangular lattice. Most unexpectedly, we observe regular helicity reversals inside skyrmions with an unusual multiple-ring structure.Keywords
This publication has 18 references indexed in Scilit:
- Near room-temperature formation of a skyrmion crystal in thin-films of the helimagnet FeGeNature Materials, 2010
- Real-space observation of a two-dimensional skyrmion crystalNature, 2010
- Real-Space Observation of Helical Spin OrderScience, 2006
- Distorted perovskite withconfiguration as a frustrated spin systemPhysical Review B, 2003
- Magnetic Vortex Core Observation in Circular Dots of PermalloyScience, 2000
- Spontaneous Bubble Domain Formation in a Layered Ferromagnetic CrystalScience, 1999
- Phase transitions with spontaneous modulation-the dipolar Ising ferromagnetPhysical Review B, 1982
- Lorentz microscopy of bubble domains and changes in domain wall state in hexaferritesphysica status solidi (a), 1973
- Bubble domains in magnetostatically coupled garnet filmsApplied Physics Letters, 1973
- Anisotropic Superexchange Interaction and Weak FerromagnetismPhysical Review B, 1960