Magnetic skyrmion is a topologically protected whirling spin texture in nanoscale. Its small size, topologically-protected stability, and solitonic characteristics together hold great promises for future spintronics applications. To translate such compelling features into practical spintronic devices, a key challenge lies in achieving effective control of skyrmion properties, such as size, density, and thermodynamic stability. Here, we report the discovery of ferroelectrically tunable skyrmions in ultrathin BaTiO3/SrRuO3 bilayer heterostructures. The ferroelectric proximity effect at the BaTiO3/SrRuO3 heterointerface can trigger a sizable Dzyaloshinskii-Moriya interaction, thus stabilizing robust high-density skyrmions.
The skyrmion size in this system can be minimized down to approximately 10 nm. Moreover, by manipulating the ferroelectric polarization of the BaTiO3 layer, we achieve local, switchable and nonvolatile tunability of both skyrmion density and thermodynamic stability. Such ferroelectric control of skyrmion properties heralds a novel approach to simultaneously enhance in the integratability and addressability of skyrmion-based functional devices.