  Magnetic skyrmions are nanoscale windings of the spin configuration that hold
great promise for technology due to their topology-related properties and
extremely reduced sizes. After the recent observation at room temperature of
sub-100 nm skyrmions stabilized by interfacial chiral interaction in magnetic
multilayers, several pending questions remain to be solved, notably about the
means to nucleate individual compact skyrmions or the exact nature of their
motion. In this study, a method leading to the formation of magnetic skyrmions
in a micrometer-sized nanotrack using homogeneous current injection is
evidenced. Spin-transfer-induced motion of these small
electricalcurrent-generated skyrmions is then demonstrated and the role of the
out-of-plane magnetic field in the stabilization of the moving skyrmions is
also analysed. The results of these experimental observations of spin torque
induced motion are compared to micromagnetic simulations reproducing a granular
type, non-uniform magnetic multilayer, in order to address the particularly
important role of the magnetic inhomogeneities on the current-induced motion of
sub-100 nm skyrmions, for which the material grains size is comparable to the
skyrmion diameter.
