Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 11: FS: Topological Defects in Electronic Systems (with TT)
MA 11.4: Invited Talk
Tuesday, March 23, 2010, 11:00–11:30, H20
Skyrmion Lattices in Pure Metals and Strongly Doped Semiconductors — •Christian Pfleiderer — Physik Department E21, Technische Universität München, D-85748 Garching, Germany
For a long time it was anticipated theoretically, that chiral magnets may support topological defects with the characteristics of skyrmions. We used neutron scattering and measurements of the Hall effect to identify the formation of two-dimensional lattices of skyrmion lines, a new form of magnetic order, in metallic and semiconducting B20 compounds, namely MnSi [1,2], Mn1−xCoxSi, Mn1−xFexSi and Fe1−xCoxSi [3]. The skyrmion lattices share remarkable similarities with vortex lattices in type II superconductors. For instance, they may exhibit domain formation and complex morphologies as seen, e.g., in ultrapure Nb [4]. Moreover, the pinning of the skyrmion lattices to the crystal lattice is extremely weak. In fact, they may be viewed as a spin crystal that is essentially disconnected from the atomic lattice. Our study establishes magnetic materials lacking inversion symmetry as an arena for new forms of order composed of topologically stable spin configurations.
[1] S. Mühlbauer, et al. , Science 323, 915 (2009).
[2] A. Neubauer, et al., Phys. Rev. Lett. 102, 186602 (2009).
[3] W. Münzer, et al., arXiv/0902.2587.
[4] S. Mühlbauer, et al., Phys. Rev. Lett. 102, 136409 (2009).