Tailoring Topological Magnetic States in Multilayer Nanostructures: Bloch Points, Chiral Bobbers, and Skyrmion Tubes.

Topological magnetic textures-including skyrmions, Bloch points, and chiral bobbers-exhibit extraordinary properties with significant potential for advanced information technologies. However, achieving precise control over specific topological states requires an understanding of their formation mechanisms and stabilization criteria in nanoscale materials. Our work addresses this challenge by investigating how tailored interactions in ferromagnetic multilayers govern the emergence of specific topological configurations. In this study, we investigate topological magnetic structures in ferromagnetic multilayers, focusing on the interplay between magnetic anisotropy, the Dzyaloshinskii-Moriya interaction, and interlayer exchange coupling. We demonstrate how these interactions govern the formation and stability of diverse 3D topological configurations, including Bloch-point-like structures, conical skyrmions, chiral bobbers, and skyrmion tubes. Optimal conditions for stabilizing specific defect types have been identified and phase diagrams have been constructed as a function of material parameters. These findings provide insights into the controlled design of magnetic textures for advanced spintronic applications.