Antiferromagnetic Skyrmionics: generating and controlling topological textures

Whirling magnetic textures could emerge as topologically protected information bits for next-generation computing. However, their practical adoption has been inhibited by susceptibility to stray fields, internal dipole fields, slow speed or sideway motion. To alleviate these issues, there has been a surge of interest in antiferromagnetic (AFM) analogues, predicted to be robust, scalable and ultra-fast. Yet, experimental progress in this field has been inhibited by the difficulty to visualize and control AFM textures via standard techniques.

To this effect, I will present a recently developed AFM vector-mapping technique¹ to image variations of the AFM order. Then, I will outline a general field-free approach, employing the Kibble–Zurek transition, to reversibly create a wide multichiral family of topological AFM textures, including exotic (anti)merons, bimerons². In epitaxial films and free-standing membranes of the earth-abundant oxide α-Fe₂O₃ these nanoscale textures can be nucleated and stabilized at room temperature. Particularly, the presence of widely tunable anisotropy³ and exchange^1,2 interactions enable unprecedented reversible control over their dimensions and orientation. Then, I will present how we may realize the hitherto undiscovered AFM skyrmions in α-Fe₂O₃, by introducing new symmetry breaking interactions. Lastly, I will outline the path ahead for AFM skyrmionics, discussing how our results may be translatable to a broad class of AFM systems^3,4, and sharing how electrical pathways can be exploited to control members of the topological family.

1. F Chmiel et al. Nat Mater 17, 581 (2018)

2. H Jani et al. Nature 590, 74 (2021)

3. H Jani et al. Nat Comm 12, 1668 (2021)

4. Z Lim, H Jani et al. MRS Bulletin, In Press (2021)