Magnetic stripes and skyrmions with helicity reversals
| Autor: | Xiuzhen Yu, Yusuke Tokunaga, Naoto Nagaosa, Yoshio Kaneko, Koji Kimoto, Maxim Mostovoy, Weizhu Zhang, Yoshinori Tokura, Yoshio Matsui |
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| Přispěvatelé: | Theory of Condensed Matter |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Magnetic domain
Lorentz transformation Barium Compounds Electrons Electron Ba ferrite FILMS Ferric Compounds Corrections Topological defect Bloch lines symbols.namesake Magnetics Microscopy Electron Transmission Hexagonal lattice WEAK FERROMAGNETISM Physics Multidisciplinary Condensed matter physics CRYSTAL Skyrmion REAL-SPACE OBSERVATION Helicity rotated spins Magnetic field Nanostructures LATTICE Models Chemical Physical Sciences symbols Condensed Matter::Strongly Correlated Electrons Lorentz TEM topological defects Scandium BUBBLE DOMAINS |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America, 109(23), 8856-8860. NATL ACAD SCIENCES |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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