  Skyrmion-based spin torque nano-oscillators are potential next-generation
microwave signal generators. However, ferromagnetic skyrmion-based spin torque
nano-oscillators cannot reach high oscillation frequencies. In this work, we
propose to use the circular motion of an antiferromagnetic skyrmion to create
the oscillation signal in order to overcome this obstacle. Micromagnetic
simulations demonstrate that the antiferromagnetic skyrmion-based spin torque
nano-oscillators can produce high frequencies (tens of GHz). Furthermore, the
speed of the circular motion for an antiferromagnetic skyrmion in a nanodisk is
analytically derived, which agrees well with the results of numerical
simulations. Our findings are useful for the understanding of the inertial
dynamics of an antiferromagnetic skyrmion and the development of future
skyrmion-based spin torque nano-oscillators.
