Local and non-local chirality breaking effects in curvilinear nanoarchitectures

The main origin of the chiral symmetry breaking and, thus, for the magnetochiral effects in magnetic materials is associated with an antisymmetric exchange interaction, the intrinsic Dzyaloshinskii-Moriya interaction (DMI) [1,2]. The later manifests itself in magnetic materials or layer stacks with structural space inversion symmetry breaking. The DMI is responsible for the formation of non-trivial chiral and topological spin textures (e.g. skyrmions, bubbles, homochiral spirals and domain walls), that are envisioned to be utilized for prospective spintronic devices. At present, tailoring of magnetochirality is done by the selection of materials and adjustment of their composition.
Alternatively, we demonstrate that space inversion symmetry breaking of the magnetic order parameter appears in geometrically curved systems [3]. In curvilinear ferromagnets, curvature governs the appearance of geometry-induced chiral and anisotropic responses, which introduce a new toolbox to create artificial chiral nanostructures from achiral magnetic materials suitable for the stabilization of non-trivial chiral textures [4,5,6]. Moreover, curvilinear geometry also leads to the appearance of non-local chiral effects, that arise from the asymmetry of the top and bottom surfaces and existence of both in- and out-of-plane magnetization components of different parity with respect to the reflection procedure [5]. Recently, we demonstrate the existence of non-local chiral effects in geometrically curved asymmetric permalloy cap with the vortex texture. We find that the equilibrium vortex core obtain both bend and curling deformation, that are dependent on the geometric symmetries and magnetic parameters.

References
[1] I. Dzyaloshinsky, J. Phys. Chem. Solids 4 (1958), 241.
[2] T. Moriya, Phys. Rev. Lett. 4 (1960), 228.
[3] R. Hertel, SPIN 3 (2013), 1340009.
[4] D. Makarov, et al., Adv. Mater. 34 (2021), 2101758.
[5] D. D. Sheka, et al., Commun. Phys. 3 (2020), 128.
[6] O. M. Volkov, et al., Phys. Rev. Lett. 123 (2019), 077201.