Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 10: Non-Skyrmionic Magnetic Textures
MA 10.4: Vortrag
Montag, 5. September 2022, 16:00–16:15, H47
Screw dislocations in chiral magnets — •Maria Azhar1, Volodymyr Kravchuk1,2, and Markus Garst1 — 1Karlsruhe Institute of Technology, Germany — 2Bogolyubov Institute for Theoretical Physics of National Academy of Sciences of Ukraine, Kyiv, Ukraine
The Dyzaloshinskii-Moriya interaction stabilizes helimagnetic order in cubic chiral magnets for a large range of temperatures and applied magnetic field. In this helimagnetic phase the magnetization varies only along the helix axis, that is aligned with the applied field, giving rise to a one-dimensional periodic magnetic texture. This texture shares many similarities with generic lamellar order like cholesteric liquid crystals, for example, it possesses disclination and dislocation defects [1]. Here, we investigate both analytically and numerically screw dislocations of helimagnetic order. Whereas the far-field of these defects is universal, we find that various core structures can be realized even for the same Burgers vector of the screw dislocation. In particular, we identify screw dislocations with smooth magnetic core structures, that close to the transition to the field-polarized phase continuously connect either to vortices of the XY-order parameter or to skyrmion strings. In addition, close to zero fields we find singular core structure comprising a chain of Bloch points with alternating topological charge [2].
[1] P. Schoenherr et al. Nature Physics 14, 465 (2018).
[2] M. Azhar, V. Kravchuk, and M. Garst, Physical Review Letters 128, 157204 (2022).