Apr 10, 2018; Colloquium
Physikalisches Kolloquium: Skyrmions and antiskyrmions in crystals with axial symmetry
Experimental Physics V
Center for Electronic Correlations and Magnetism Institute of Physics
University of Augsburg
01062 Dresden
Veranstaltungseinladung als pdf-Download.
Kurzfassung: Néel-type skyrmions [1] and antiskyrmions [2], recently realized in axially symmetric magnets, are substantially different from Bloch-type skyrmions, widely explored in chiral cubic magnets, in terms of their internal magnetic structure, their stability range, as well as their response to external stimuli. More specifically, the axial symmetry of the host gives rise to an extended stability range by restricting the wave vectors of magnetic modulations to the plane normal to the high-symmetry axis. Since such skyrmions and antiskyrmions do not co-align with external magnetic fields, instead their orientation keeps confined to the high-symmetry axis of the host, they become asymmetric in oblique magnetic fields [3, 4]. This distortion gives rise to an additional degree of freedom, which affects their dynamics. Moreover, it may result in either an attractive or a repulsive skyrmion-to-skyrmion interaction, depending on the relative orientation of the pair. Corresponding experimental results on lacunar spinel and Heusler alloys hosting Néel-type skyrmions and antiskyrmions, respectively, will also be reviewed together with the magnetoelectric nature of these new skyrmion prototypes [1, 2, 5, 6].
[1] I. Kézsmárki et al., Nat. Mater. 14, 1116 (2015).
[2] A. K. Nayak et al., Nature 548, 561 (2017).
[3] A. O. Leonov and I. Kézsmárki, Phys. Rev. B 96, 014423 (2017). [4] A. O. Leonov and I. Kézsmárki, Phys. Rev. B 96, 214413 (2017). [5] E. Ruff et al., Sci. Adv. 1, e1500916 (2015).
[6] S. Bordács et al., Sci. Rep. 7, 7584 (2017).
Biographie: István Kézsmárki is professor in solid state physics, spectroscopy and magnetism. Current research interest: i) magnetic and spectroscopic studies on skyrmion host compounds; ii) optical properties of multiferroic materials, optical magnetoelectric effect, unidirectional light transmission; iii) magneto-optical spectroscopy of collective excitations in itinerant and insulating magnets; iv) spectroscopic study of correlated electron systems; v) magneto- optical diagnosis of malaria and biomedical applications of magnetic nanoparticles.