Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 11: FS: Topological Defects in Electronic Systems (with TT)

MA 11.1: Hauptvortrag

Dienstag, 23. März 2010, 09:30–10:00, H20

Skyrmions in Chiral Magnets — •Ulrich K. Rößler, Andrei A. Leonov, Anna B. Butenko, and Alexei N. Bogdanov — IFW Dresden

In non-centrosymmetric magnets the chiral Dzyaloshinskii-Moriya (DM) exchange stabilizes tubular baby-Skyrmions. These are topologically non-trivial localized, but smooth and static textures of a spin system. Chiral Skyrmionic states may exist in various magnetic systems as the chiral DM-couplings stem from the leading spin-orbit effect, if they are allowed by crystal symmetry. Extended Skyrmionic textures are determined by the stability of the localized solitonic Skyrmion cores and their geometrical incompatibility, which frustrates a homogeneous space-filling. Two-dimensional models for these inhomogeneous magnetic states bear strong similarity with Abrikosov-lattices. Just as cylindrical vortices arrange into regular arrays in type-II superconductors, Skyrmions may form ordered arrays in chiral magnets. Basic phenomenological continuum theory suggests that a cornucopia of unexpected effects can be found in these chiral magnets. The isolated particle-like Skyrmion excitations may undergo confinement near the magnetic transition, and these molecular units may finally condense into extended mesophases. This magnetic ’Skyrmionic matter’ strongly resembles chiral nematic liquid crystal textures. The underlying theoretical ideas shed new light on more fundamental question about the appearance of countable units in a continuum, and mechanisms for the formation of self-generated amorphous states.