Visualizing strain, topology and chirality in antiferromagnetic domain wall networks by spin-polarized STM

Materials with antiferromagnetic order have recently emerged as promising candidates in spintronics based on their beneficial characteristics such as vanishing stray fields and ultra-fast dynamics [1]. At the same time more complex localized non-coplanar magnetic states as for instance skyrmions are in the focus of applications due to their intriguing properties such as the topological Hall effect [2]. Recently a conceptual shift has occurred to envision the use of such magnetic defects not only in one-dimensional race track devices, but to exploit their unique properties in two-dimensional networks. Here we use local strain in a collinear antiferromagnet to induce non-coplanar domain wall junctions, which connect in a very specific way to form extended networks. We combine spin-polarized scanning tunneling microscopy with density functional theory to characterize the different building blocks of the network, and unravel the origin of the handedness of triple-junctions and the size of the arising topological orbital moments [3].

References:

[1] Jungwirth, T., Marti, X., Wadley, P. et al. Antiferromagnetic spintronics. Nature Nanotech 11, 231–241 (2016).

[2] Nagaosa, N., Tokura, Y. Topological properties and dynamics of magnetic skyrmions. Nature Nanotech 8, 899–911 (2013).

[3] Link to the arXiv paper for the above abstract: https://doi.org/10.48550/arXiv.2408.12580