Topological spin textures have attracted much attention both for fundamental physics and spintronics applications. Among them, antiskyrmions possess a unique spin configuration with Bloch-type and Néel-type domain walls owing to anisotropic Dzyaloshinskii–Moriya interaction in the non-centrosymmetric crystal structure. However, antiskyrmions have thus far only been observed in a few Heusler compounds with D2d symmetry. Here we report a new material, Fe1.9Ni0.9Pd0.2P, in a different symmetry class (S4), in which antiskyrmions exist over a wide temperature range that includes room temperature, and transform into skyrmions on changing magnetic field and lamella thickness. The periodicity of magnetic textures greatly depends on the crystal thickness, and domains with anisotropic sawtooth fractals were observed at the surface of thick crystals and attributed to the interplay between the dipolar interaction and the Dzyaloshinskii–Moriya interaction as governed by crystal symmetry. Our findings provide an arena in which to study antiskyrmions, and should stimulate further research on topological spin textures and their applications.
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We thank N. Nagaosa, W. Koshibae, Y. Tokunaga and T. Arima for fruitful discussions. We also thank F. S. Yasin for technical support for the DPC-STEM measurement and K. Nakajima for technical support for the preparation of the FIB sample. This work was supported by JSPS Grant-in-Aids for Scientific Research (grant numbers 17K18355, 18H05225, 19H00660 and 20K15164), JST CREST (grant numbers JPMJCR1874 and JPMJCR20T1) and the Humboldt/JSPS International Research Fellow Programme (grant number 19F19815).
The authors declare no competing interests.
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The panels show the magnetization in various layers at different depth of a film as obtained from a three-dimensional micromagnetic simulation. The simulated sample measures 1.6 µm × 0.8 µm × 5.3 µm where periodic boundary conditions are applied in the x–y-plane to mimic an extended plate. The colour encodes the direction of the magnetization in the plane and black/white encodes the out-of-plane component, as indicated by the square-shaped antiskyrmion on the bottom right panel, which also sketches the DMI-preferred helicities. In addition, small arrows also show the direction of the in-plane components of the magnetization.
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Karube, K., Peng, L., Masell, J. et al. Room-temperature antiskyrmions and sawtooth surface textures in a non-centrosymmetric magnet with S4 symmetry. Nat. Mater. 20, 335–340 (2021). https://doi.org/10.1038/s41563-020-00898-w