Multilayer Metamaterials with Ferromagnetic Domains Separated by Antiferromagnetic Domain Walls

AbstractMagnetic nano‐objects possess great potential for more efficient data processing, storage, and neuromorphic‐type applications. Using high perpendicular magnetic anisotropy synthetic antiferromagnets in the form of multilayer‐based metamaterials, the antiferromagnetic interlayer exchange energy is purposefully reduced below the out‐of‐plane demagnetization energy, which controls magnetic domain formation. In this unusual magnetic energy regime, as demonstrated via macroscopic magnetometry and microscopic Lorentz transmission electron microscopy, it becomes possible to stabilize nanometer‐scale stripe and bubble textures consisting of ferromagnetic out‐of‐plane domain cores separated by antiferromagnetic in‐plane Bloch‐type domain walls. This unique coexistence of mixed ferromagnetic/antiferromagnetic 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 depth‐wise alternating chirality.