Ferroelectric geometry-modulated magnetic topological structures in PbTiO3/SrRuO3 superlattices

The recent discovery of topological structures has opened the door for exciting physics and emergent properties. Polar vortex domains and flux-closure domains in ferroelectric materials, as well as skyrmions and magnetic bubbles in ferromagnetic materials, are characterized by their small size, high stability, and excellent controllability, making them highly suitable for applications in information storage and sensing technologies. Although ferroelectricity and ferromagnetism are fundamentally antagonistic, researchers have discovered single-phase multiferroic materials (e.g., BiFeO3) and composite multiferroic materials (e.g., magnetoelectric heterostructures) that exhibit both properties. However, the coexistence of polar and magnetic topological structures within the same system has not yet been confirmed. Here, we demonstrate the coexistence of polar flux-closure domains and magnetic topological structures in PbTiO3/SrRuO3 ferroelectric/ferromagnetic superlattices systems. By manipulating the geometric characteristics of the polar topological structures, we achieve tunable magnetic topological signals. Strain distribution analysis and first-principles calculations reveal that the large strain gradients induced by lattice tilting are the primary factor influencing the Dzyaloshinskii–Moriya interaction. Finally, we demonstrated the tunability of the Hall resistivity through domain structure manipulation via electric field application. Our results demonstrate that polar and magnetic topological structures can stably coexist within the same system and exhibit potential coupling mechanisms. This provides new insights into tuning magnetic properties from the perspective of ferroelectric geometric structures.