  Direct observation of vortex states in an antiferromagnetic layer have been
recently reported [Wu, et al, Nature Phys. 7, 303 (2011)]. In contrast to their
analogues in ferromagnetic systems, namely in nanomagnets, the vortex core of
antiferromagnets are not expected (and have not been observed) to present
gyrotropic or any other remarkable dynamics, even when external fields are
applied. Using simulated annealing and spin dynamics techniques we have been
able to describe a number of properties of such a vortex state. Besides of
being in agreement with reported results, our results also indicate, whenever
applied to antiferromagnetic nanodisks, that the presence of holes in the
sample may induce two types of motions for this vortex. Its dynamics depends
upon the relative separation between its core and the hole: when they are very
apart the vortex core oscillates near the nanodisk center (its equilibrium
position); while, if they are sufficiently close, the core moves towards the
hole where it is captured and remains static.
