Stability and lifetime of antiferromagnetic skyrmions

• Published in: Physical Review B
• Main Authors: Bessarab, Pavel, Yudin, D., Gulevich, D. R., Wadley, P., Titov, M., Tretiakov, Oleg A.
• Other Authors: Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Physical Society (APS) 2019
• Subjects: Skyrmions; Antiferromagnets; Dzyaloshinskii-Moriya interaction; Eðlisfræði; Þéttefnisfræði; Flop; Misi; Stripe; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/1527; https://doi.org/10.1103/PhysRevB.99.140411

Publisher's version (útgefin grein) The two-dimensional Heisenberg exchange model with out-of-plane anisotropy and a Dzyaloshinskii-Moriya interaction is employed to investigate the lifetime and stability of antiferromagnetic (AFM) skyrmion as a function of temperature and external magnetic field. An isolated AFM skyrmion is metastable at zero temperature in a certain parameter range set by two boundaries separating the skyrmion state from the uniform AFM phase and a stripe domain phase. The distribution of the energy barriers for the AFM skyrmion decay into the uniform AFM state complements the zero-temperature stability diagram and demonstrates that the skyrmion stability region is significantly narrowed at finite temperatures. We show that the AFM skyrmion stability can be enhanced by an application of magnetic field, whose strength is comparable to the spin-flop field. This stabilization of AFM skyrmions in external magnetic fields is in sharp contrast to the behavior of their ferromagnetic counterparts. Furthermore, we demonstrate that the AFM skyrmions are stable on the timescales of milliseconds below 50 K for realistic material parameters, making it feasible to observe them in modern experiments. P.F.B. acknowledges support from the Icelandic Research Fund (Grant No. 163048-052), the University of Iceland Research Fund, and Alexander von Humboldt Foundation. P.F.B., D.Y., D.R.G., and M.T. acknowledge support from the Russian Science Foundation under Project No. 17-12-01359. The work of M.T. was partially supported by ICC-IMR, Tohoku University (Japan). O.A.T. acknowledges support by a grant of the Center for Science and Innovation in Spintronics (Core Research Cluster), Tohoku University, by Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST “MISi” (No. K2-2019-006), implemented by a governmental decree dated 16th of March 2013, N 211, and by JSPS and RFBR under the Japan-Russia Research Cooperative Program. Peer Reviewed