  L10-FePt distinguishes itself for its ultrahigh perpendicular magnetic
anisotropy (PMA), which enables memory cells with sufficient thermal stability
to scale down to 3 nm. The recently discovered "bulk" spin-orbit torques in
L10-FePt provide an efficient and scalable way to manipulate the L10-FePt
magnetization. However, the existence of external field during the switching
limits its practical application, and therefore field-free switching of the
L10-FePt is in highly demand. In this manuscript, we demonstrate the field-free
switching of the L10-FePt by growing it on vicinal MgO (001) substrates. This
method is different from previously established strategies, as it does not need
to add other functional layers or create asymmetry in the film structure. We
demonstrate the field-free switching is robust and can withstand strong field
disturbance up to ~1 kOe. The dependence on vicinal angle, film thickness, and
growth temperature demonstrated a wide operation window for the field-free
switching of the L10-FePt. We confirmed that the physical origin of the
field-free switching is the vicinal surface-induced the tilted anisotropy of
L10-FePt. We quantitatively characterize the spin-orbit torques in the L10-FePt
films, and found the spin-orbit torques are not significantly influenced by the
lattice strain from vicinal substrates. Our results extend beyond the
established strategies to realize field-free switching, and potentially could
be applied to other magnetic and antiferromagnetic systems.
