  We report on the stabilization of ferromagnetic skyrmions in zero external
magnetic fields, in exchange-biased systems composed of
ferromagnetic-antiferromagnetic (FM-AFM) bilayers. By performing atomistic spin
dynamics simulations, we study cases of compensated, uncompensated, and partly
uncompensated FM-AFM interfaces, and investigate the impact of important
parameters such as temperature, inter-plane exchange interaction,
Dzyaloshinskii-Moria interaction, and magnetic anisotropy on the skyrmions
appearance and stability. The model with an uncompensated FM-AFM interface
leads to the stabilization of individual skyrmions and skyrmion lattices in the
FM layer, caused by the effective field from the AFM instead of an external
magnetic field. Similarly, in the case of a fully compensated FM-AFM interface,
we show that FM skyrmions can be stabilized. We also demonstrate that
accounting for interface roughness leads to stabilization of skyrmions both in
compensated and uncompensated interfaces. Moreover, in bilayers with a rough
interface, skyrmions in the FM layer are observed for a wide range of exchange
interaction values through the FM-AFM interface, and the chirality of the
skyrmions depends critically on the exchange interaction.
