Non-local chirality breaking in curvilinear magnetic nanoarchitectures

In magnetism, the magnetization vector remains unaltered upon the space inversion symmetry transformation but changes its sign with time inversion. Breaking of the inversion symmetry within the magnetic lattice unit cell or sample's shape introduces a chiral Dzyaloshinskii-Moriya interaction (DMI) [1,2], which manifests itself in the formation of non-trivial chiral and topological spin textures with a given magnetochirality. The latter can be tailored either at the intrinsic structural level [3] by the adjustment of a material composition or geometrically by the formation of versatile chiral and anisotropic responses in curved magnetic objects even for standard magnetic materials [4,5,6]. Here, we demonstrate the existence of non-local chiral effects in geometrically curved asymmetric permalloy cap with a vortex texture. Using the full-scale simulation we study how the texture is changing with respect to the introduced sample asymmetry. Namely, the equilibrium vortex core obtain both bend and curling deformations, that arise from the asymmetry of the top and bottom surfaces and existence of the non-local chiral effects [7]. The obtained results were confirmed by magnetic imaging using transmission electron microscopy based electron holography for the asymmetric permalloy cap.