Ferrimagnetic Skyrmions in Topological Insulator/Ferrimagnet Heterostructures |
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Authors: | Hao Wu Felix Groß Bingqian Dai David Lujan Seyed Armin Razavi Peng Zhang Yuxiang Liu Kemal Sobotkiewich Johannes Förster Markus Weigand Gisela Schütz Xiaoqin Li Joachim Gräfe Kang L Wang |
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Affiliation: | 1. Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095 USA;2. Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart, 70569 Germany;3. Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Austin, TX, 78712 USA |
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Abstract: | Magnetic skyrmions are topologically nontrivial chiral spin textures that have potential applications in next-generation energy-efficient and high-density spintronic devices. In general, the chiral spins of skyrmions are stabilized by the noncollinear Dzyaloshinskii–Moriya interaction (DMI), originating from the inversion symmetry breaking combined with the strong spin–orbit coupling (SOC). Here, the strong SOC from topological insulators (TIs) is utilized to provide a large interfacial DMI in TI/ferrimagnet heterostructures at room temperature, resulting in small-size (radius ≈ 100 nm) skyrmions in the adjacent ferrimagnet. Antiferromagnetically coupled skyrmion sublattices are observed in the ferrimagnet by element-resolved scanning transmission X-ray microscopy, showing the potential of a vanishing skyrmion Hall effect and ultrafast skyrmion dynamics. The line-scan spin profile of the single skyrmion shows a Néel-type domain wall structure and a 120 nm size of the 180° domain wall. This work demonstrates the sizable DMI and small skyrmions in TI-based heterostructures with great promise for low-energy spintronic devices. |
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Keywords: | Dzyaloshinskii–Moriya interaction ferrimagnetic skyrmions ferrimagnets topological insulators |
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