Topological states in magnetic multilayers with hybrid anisotropy and Dzyaloshinskii–Moriya interaction

Abstract

Magnetic multilayers with engineered anisotropy and controlled Dzyaloshinskii–Moriya interaction offer a versatile platform for stabilizing complex three-dimensional topological structures. In this article, we investigate the magnetic states in an exchanged-coupled four-layer ferromagnetic film composed of layers with perpendicular and in-plane magnetic anisotropies. By introducing the Dzyaloshinskii–Moriya interaction into single layer and bi-layer, we demonstrate the stabilization of a variety of topological textures in the film during magnetization processes. Using micromagnetic simulations, we show that tuning the Dzyaloshinskii–Moriya interaction strength and anisotropy of individual layers governs the emergence of distinct topological phases, including conical skyrmions, kπ-skyrmion tubes (k = 1, 2), Bloch points, and chiral bobbers. We identify the conditions necessary for stabilizing these states and construct phase diagrams mapping the field-driven transitions. These results provide insight into the mechanisms of topological state formation and may contribute to the development of magnetic multilayer systems for multi-bit memory and neuromorphic computing applications.