Chiral spin textures in amorphous iron germanium thick films

Abstract

To date, the emergence of topological vector fields has almost exclusively been associated with a global inversion symmetry breaking that causes a vector spin exchange, known as Dzyaloshinskii-Moriya interaction. Engineering a locally varying vector spin exchange has been proposed as an alternative to stabilize anisotropic topological states. I will present experimental evidence of 3D chiral spin textures stabilized in amorphous iron germanium thick films with local inversion symmetry breaking and DMI [1]. Lorentz microscopy with exit wave reconstruction revealed both isotropic Bloch skyrmions and anisotropic solitons, which are accompanied by a reduced orbital-to-spin moment ratio, underling the importance of disordered electron orbitals and random DMI. Persistent switching of anisotropic skyrmions corroborate variations in magnetic anisotropy and exchange, and confirm a degenerate spin chirality and particle-like properties.