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Skyrmions are topologically protected spin textures, which can be used in spintronic devices for information storage and processing. Ferromagnetic skyrmions attracted a lot of attention because they are small in size, better than domain walls at avoiding pinning sites, and can be moved very fast by electric currents in ferromagnet/heavy-metal bilayers due to novel spin-orbit torques [1, 2]. Meanwhile, the ferromagnetic skyrmions also have certain disadvantages to employ them in spintronic devices, such as the presence of stray fields and transverse to current dynamics [2]. To avoid these unwanted effects, we propose to look at these topological objects in antiferromagnets. An antiferromagnetic skyrmion has no stray fields and its dynamics are faster compared to its ferromagnetic analogue. More importantly, due to unusual topology it experiences no skyrmion Hall effect [3], and thus is a better candidate for spintronic applications [4]. I will also discuss the lifetimes of both antiferromagnetic skyrmions at finite temperatures [5]. Lastly, I will talk about antiskyrmions – anisotropic topological objects, which were recently observed in systems with anisotropic Dzyaloshinskii-Moriya interaction [6]. I will explain their long lifetimes and current driven dynamics in antiferromagnets based on the transformation between skyrmion and antiskyrmion.
[1] I. Ado, O. A. Tretiakov, and M. Titov, Phys. Rev. B 95 , 094401 (2017).
[2] K. Litzius, I. Lemesh, B. Kruger, P. Bassirian, L. Caretta, K. Richter, F. Buttner, K. Sato, O. A. Tretiakov, J. Forster, R. M. Reeve, M. Weigand, I. Bykova, H. Stoll, G. Schutz, G. S. D. Beach, and M. Klaui, Nature Physics 13 , 170 (2017).
[3] J. Barker and O. A. Tretiakov, Phys. Rev. Lett. 116 , 147203 (2016).
[4] C. A. Akosa, O. A. Tretiakov, G. Tatara, and A. Manchon, submitted to Phys. Rev. Lett. (2017); arXiv:1709.02931.
[5] P. F. Bessarab, D. Yudin, D. R. Gulevich, P. Wadley, M. Titov, and O. A. Tretiakov, submitted to Phys. Rev. Lett. (2017); arXiv:1709.04454.
[6] A. K. Nayak, V. Kumar, T. Ma, P. Werner, E. Pippel, R. Sahoo, F. Damay, U. K. Rößler, C. Felser, and S. S. P. Parkin, Nature 548, 561 (2017).
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