Theory of magnetism and topological spin textures in disordered magnets: a case study of amorphous FeGe

A microscopic understanding of magnetism and topological spin textures in disordered systems is both fundamentally intriguing and technologically relevant for developing robust, flexible, and scalable spintronic devices that can surpass the limitations of crystalline systems. Here, we study the magnetism and topology in amorphous FeGe using first-principles calculations, ab-initio molecular dynamics, and Monte-Carlo simulations. Our results reveal that amorphous magnets exhibit diverse magnetic interactions that are highly sensitive to the local atomic environment and can be significantly stronger than those in crystalline magnets. In addition, these intrinsic magnetic interactions naturally lead to the formation of topological spin textures rather than conventional Dzyaloshinskii-Moriya interactions. In fact, such spin textures have recently been reported in amorphous FeGe [1]. These insights demonstrate that topological spin textures can arise intrinsically in disordered magnets, opening a new materials paradigm for future microelectronics.

[1] R. Streubel, D. S. Bouma, F. Bruni, X. Chen, P. Ercius, J. Ciston, A. T. N'Diaye, S. Roy, S. D. Kevan, P. Fischer, F. Hellman, Chiral Spin Textures in Amorphous Iron–Germanium Thick Films. Adv. Mater. 2021, 33, 2004830. https://doi.org/10.1002/adma.202004830