  Recent advances on the stabilization and manipulation of chiral magnetization
configurations in systems consisting in alternating atomic layers of
ferromagnetic and non-magnetic materials hold promise of innovation in
spintronics technology. The low dimensionality of the systems promotes spin
orbit driven interfacial effects like antisymmetric Dzyaloshinskii-Moriya
interactions (DMI) and surface magnetic anisotropy, whose relative strengths
may be tuned to achieve stable nanometer sized magnetic objects with fixed
chirality. While in most of the cases this is obtained by engineering complex
multilayers stacks in which interlayer dipolar fields become important, we
consider here a simple epitaxial trilayer in which a ferromagnet, with variable
thickness, is embedded between a heavy metal and graphene. The latter enhances
the perpendicular magnetic anisotropy of the system, promotes a Rashba-type
DMI, and can sustain very long spin diffusion length. We use a layer-resolved
micromagnetic model (LRM) to describe the magnetization textures and their
chirality. Our results demonstrate that for Co thickness larger than 3.6 nm, a
skyrmion having an intrinsic mixed Bloch-N\'eel character with
counter-clock-wise chirality is stabilized in the entire (single) Co layer.
Noteworthy, for thicknesses larger than 5.4 nm, the skyrmion switches its
chirality, from counter-clock-wise to clock-wise.
