Stability of atomic-sized skyrmions in antiferromagnetic bilayers

We perform a stability analysis of an isolated atomic-sized antiferromagnetic skyrmion (AFM-Sk), formed on the superior layer of a magnetic bilayer. The coupling between both square lattices acts as an effective staggered magnetic field that stabilizes the AFM-Sk and reduces its radius. A suitable anisotropy constant of the bottom layer material keeps it close to the homogeneous AFM state. We compare the energy of the AFM-Sk with the energy of the AFM ground state. In addition, an estimation of the energy barrier that protects the skyrmion from being destabilized is provided and its value determined to be in the order of ∼300 K. The remarkable reduction in the skyrmion radius towards atomic size and avoiding an external magnetic field are key points in order to increase our ability to manipulate AFM-Sk on skyrmionic devices. Our calculations provide an insight into novel ways to create and manipulate AFM-Sk at the atomic scale.