Formation of Topological Polar Texture in Ferroelectric Ba _0.8 Sr _0.2 TiO ₃ Thin Films

Abstract Topological polar textures have garnered significant attention for next‐generation electronic devices due to associated emergent functionalities (e.g., chirality, enhanced conductivity, and negative capacitance). Most studies stabilize topological textures using depolarization field in ferroelectric‐ dielectric superlattices or heterostructures; however, the lack of direct electrical contacts dramatically hinders the corresponding field‐driven control and applications. Here, the formation of electric‐field‐switchable Néel‐type polar skyrmions at room temperature is demonstrated in Ba 0.8 Sr 0.2 TiO 3 (BSTO) thin films directly grown on metallic SrRuO 3 electrodes. In this study, strategic Sr substitution is employed to engineer the Landau energy landscape of ferroelectric material BaTiO 3 , which eventually facilitates the coexistence of multiple polarization states without sacrificing room‐temperature ferroelectricity. Piezoelectric force microscopy (PFM) uncovers a critical BSTO thickness to host the phenomena: conventional ferroelectric domains dominate 60‐nm thick BSTO, whereas high‐density topological polar textures emerge in 10‐nm thick BSTO. Specifically, vector‐PFM analysis identifies two stable skyrmion states in 10‐nm BSTO with convergent‐ and divergent‐ in‐plane polarization components. Importantly, an electric‐field‐driven interconversion between these topological states is demonstrated by reconfiguring the free‐energy landscape, which is also supported by the phase‐field simulations. This work provides a direct pathway of using metallic electrodes for the dynamic control of topological ferroelectrics in functional devices.