  Magnetic skyrmions are topologically-protected spin textures with attractive
properties suitable for high-density and low-power spintronic device
applications. Much effort has been dedicated to understanding the dynamical
behaviours of the magnetic skyrmions. However, experimental observation of the
ultrafast dynamics of this chiral magnetic texture in real space, which is the
hallmark of its quasiparticle nature, has so far remained elusive. Here, we
report nanosecond-dynamics of a 100 nm-size magnetic skyrmion during a current
pulse application, using a time-resolved pump-probe soft X-ray imaging
technique. We demonstrate that distinct dynamic excitation states of magnetic
skyrmions, triggered by current-induced spin-orbit torques, can be reliably
tuned by changing the magnitude of spin-orbit torques. Our findings show that
the dynamics of magnetic skyrmions can be controlled by the spin-orbit torque
on the nanosecond time scale, which points to exciting opportunities for
ultrafast and novel skyrmionic applications in the future.
