Magnetic Vortices Attract and Repel in Waves express
Two tiny magnetic vortices, called skyrmions, drift across a thin film. As they approach each other, the force between them isn't a simple attraction or repulsion, but an alternation of the two, as if two floats on water were converging and diverging, obeying an invisible wave.
It turns out that the force between skyrmions periodically changes sign: first they attract, then they repel, and this repeats with a certain step. This resembles the well-known RKKY interaction in the physics of metals, where two magnetic moments influence each other through a cloud of electrons, and this influence oscillates with distance. The scientists showed that this behavior is linked to a universal wavy "tail" in the magnetic texture of a skyrmion: that is, how the magnetization decays at the edges of the vortex.
This discovery is important for technology: knowing how skyrmions interact, one can assemble them into "molecules" and ordered structures, much like atoms arrange into crystals. Such skyrmion ensembles could become the basis for new devices for storing and processing information, where data bits move as tiny magnetic vortices, and their interactions enable computation.
Original abstract
as written by the authors arXiv:2601.17727
Understanding skyrmion-skyrmion interactions is crucial for effectively manipulating the motion of multiple skyrmions in racetrack and logic devices. However, the fundamental nature and microscopic origins of these interactions remain poorly understood. In this study, we investigate skyrmion-skyrmion interactions in chiral magnetic films and reveal that they possess intrinsic, anisotropic, and oscillatory characteristics. Specifically, we demonstrate that the attractive and repulsive forces between skyrmions oscillate with a well-defined period, akin to the Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling observed between two magnetic moments in metals. Our analysis uncovers the essential physics behind a previously unrecognized universal wavy tail in the skyrmion spin texture. Notably, the resulting RKKY-like interaction between skyrmions is universal for all tilted skyrmions, irrespective of whether the titled easy-axis is from an external field or a crystalline magnetic anisotropy. These findings introduce a novel physical principle for the design of skyrmion molecules or skyrmion superstructures, which hold significant potential for applications in skyrmion-based spintronics and neuromorphic computing.
The name "skyrmion" comes from the British physicist Tony Skyrme, who in the 1960s proposed a model of a particle as a knotted field resembling a vortex.
In science fiction, skyrmions are sometimes mentioned as possible information carriers in future quantum computers — for example, in Greg Egan's novel "Teranesia," magnetic vortices are used for data storage.