Multilayer metamaterials with mixed ferromagnetic domain core and antiferromagnetic domain wall structure

Abstract: Magnetic nano-objects possess great potential for more efficient data processing, storage and neuromorphic type of applications. Using high perpendicular magnetic anisotropy synthetic antiferromagnets in the form of multilayer-based metamaterials we purposely reduce the antiferromagnetic (AF) interlayer exchange energy below the out-of-plane demagnetization energy, which controls the magnetic domain formation. As we show via macroscopic magnetometry as well as microscopic Lorentz transmission electron microscopy, in this unusual magnetic energy regime, it becomes possible to stabilize nanometer scale stripe and bubble textures consisting of ferromagnetic (FM) out-of-plane domain cores separated by AF in-plane Bloch-type domain walls. This unique coexistence of mixed FM/AF order on the nanometer scale opens so far unexplored perspectives in the architecture of magnetic domain landscapes as well as the design and functionality of individual magnetic textures, such as bubble domains with alternating chirality.