Experimental Evidence of Chiral Ferrimagnetism in Amorphous Materials*

Inversion symmetry breaking has become a vital research in modern magnetism with phenomena including Rashba effect, spin Hall effect and Dzyaloshinskii-Moriya interaction (DMI). The latter one may stabilize chiral spin textures with topologically non-trivial properties, such as Skyrmions. So far, chiral spin textures have mainly been studied in helimagnets and thin ferromagnets with heavy-element capping. Here, we show, using the example of chiral ferrimagnetism in amorphous GdCo, that the concept of chirality driven by interfacial DMI can be generalized to complex multicomponent systems. Utilizing Lorentz microscopy and X-ray magnetic circular dichroism spectroscopy, and tailoring thickness, capping and rare-earth composition, we find that a 2nm-thick GdCo film preserves ferrimagnetism and stabilizes chiral domain walls. The type of chiral domain walls depends on the rare-earth composition/saturation magnetization, enabling a possible temperature control of the intrinsic properties of ferrimagnetic domain walls.