O. Tretiakov: Antiferromagnetic Skyrmionics

Skyrmions are topologically protected magnetic 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 current in ferromagnet/heavy-metal bilayers due to novel spin-orbit torques. 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. To avoid these unwanted effects, we propose a novel topological object: antiferromagnetic skyrmion. This topological texture 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, and thus is a better candidate for spintronic applications. I will discuss the stability and lifetimes of antiferromagnetic skyrmions at finite temperatures. Then I will make a connection to antiskyrmions - anisotropic topological objects recently observed in the systems with anisotropic Dzyaloshinskii-Moriya interaction. I will explain their lifetimes and current-driven dynamics based on the spin transformation between skyrmion and antiskyrmion.