Geometrically Tailored Skyrmions at Zero Magnetic Field in Multilayered Nanostructures

Magnetic skyrmions are chiral spin structures recently observed at room temperature in multilayer films. Their topological stability will enable high scalability in confined geometries-a sought-after attribute for device applications. Despite numerous theoretical studies examining sub-100-nm Neel skyrmions in nanostructures, in practice their ambient stability and evolution with confinement and their magnetic parameters remain to be established. Here we present the zero-field stabilization of sub-100-nm room-temperature Neel-textured skyrmions confined in Ir/Fe(x)/Co(y)/Pt nanodots over a wide range of magnetic and geometric parameters. The zero-field skyrmion size, here as small as approximately 50 nm, can be tailored by a factor of 4 with variation of dot size and magnetic interactions. Crucially, skyrmions with differing thermodynamic stability exhibit an unexpected dichotomy in confinement phenomenologies. These results establish skyrmion phenomenology in multilayer nanostructures, and prompt the synergistic use of magnetic and geometric parameters to achieve desired properties in devices.