In this work, a consortium of physicists from SPINTEC and York addressed the challenge of nucleating quantitatively proven topological magnetic textures in compensated magnets with zero net magnetization. It paves the way for extending the study of topological spin textures beyond ferromagnets, into materials with intriguing electrodynamic properties, such as antiferromagnets and altermagnets.
A topological texture, either a skyrmion or a bimeron, formed in the HM/FM/NM ferromagnetic heterostructure is employed as a template and replicated in the prototypical AFM layer through a thermal cycling procedure.
Topologically protected magnetic states in condensed matter physics, particularly antiferromagnetic (AFM) skyrmions (Sks) and bimerons (Bms), offer promising prospects for terahertz dynamics and sustained current-induced motion, thanks to their compensating multiple sub-lattice structure. However, nucleating AFM Sks and Bms is challenging due to the lack of net magnetization.
Previous attempts to imprint pre-defined Sks and Bms in a ferromagnet (FM) and transfer them to an AFM using interfacial exchange bias in FM/AFM heterostructures have been hindered by complex multilayers with discontinuities, polycrystallinity, or multipartite chiral AFMs.
Employing atomistic spin simulations, we demonstrate the viability of texture imprinting for nucleating Sks and Bms in AFMs, using a prototypical bipartite AFM layer in a multilayer structure free from discontinuities. This approach has enabled us to calculate the topological parameters of the imprinted spin textures: polarity, vorticity, and helicity, as well as intermerons axis for the case of the Bm, providing quantitative data that was previously inaccessible. Such imprinting is a crucial step towards understanding the static and dynamic properties of natural magnetic compensated textures and their unique spin transport properties.
These data were obtained during the PhD thesis of Coline Thevenard and build upon the work conducted in the PhD thesis of Miina Leiviskä.
Team: : Antiferromagnetic spintronics and Theory/Simulation
Collaboration:University of York (UK)
Funding: IRP CITRON; EPSRC EP/V007211/1; PEPR-SPIN ALTEROSPIN ANR-24-EXPR-0002
Further reading: Imprinting of skyrmions and bimerons in an antiferromagnet, C. Thevenard, M. Leiviskä, R. F. L. Evans, D. Gusakova, V. Baltz, Phys. Rev. B 111, 224429 (2025).
Local contact: Vincent Baltz, Daria Gusakova