  Spin orbit interactions are rapidly emerging as the key for enabling
efficient current-controlled spintronic devices. Much work has focused on the
role of spin-orbit coupling at heavy metal/ferromagnet interfaces in generating
current-induced spin-orbit torques. However, the strong influence of the
spin-orbit-derived Dzyaloshinskii-Moriya interaction (DMI) on spin textures in
these materials is now becoming apparent. Recent reports suggest DMI-stabilized
homochiral domain walls (DWs) can be driven with high efficiency by spin torque
from the spin Hall effect. However, the influence of the DMI on the
current-induced magnetization switching has not been explored nor is yet
well-understood, due in part to the difficulty of disentangling spin torques
and spin textures in nano-sized confined samples. Here we study the
magnetization reversal of perpendicular magnetized ultrathin dots, and show
that the switching mechanism is strongly influenced by the DMI, which promotes
a universal chiral non-uniform reversal, even for small samples at the
nanoscale. We show that ultrafast current-induced and field-induced
magnetization switching consists on local magnetization reversal with domain
wall nucleation followed by its propagation along the sample. These findings,
not seen in conventional materials, provide essential insights for
understanding and exploiting chiral magnetism for emerging spintronics
applications.
