  The current development to employ magnetic skyrmions in novel spintronic
device designs has led to a demand for room temperature-stable skyrmions of
ever smaller size. We present extensive studies on skyrmion stability in
atomistic magnetic systems in two- and three-dimensional geometries. We show
that for materials described by the same micromagnetic parameters, the
variation of the atomistic exchange between different neighbors, the stacking
order, and the number of layers of the atomic lattice can significantly
influence the rate of the thermally activated decay of a skyrmion. These
factors alone are important considerations, but it is shown that their
combination can open up novel avenues of materials design in the search for
sub-10nm skyrmions, as their lifetime can be extended by several orders of
magnitude.
