Based on density functional theory calculations, we elucidated the tunability of
the atomic structures and magnetic interactions of Co/Pt₃ interface (one layer
of hcp(0001) Co and three layers of fcc(111) Pt) and thus the skyrmion sizes using
strain. The dispersion relations of the spin spiral in the opposite directions, E(q)
and E(-q), were evaluated based on generalized Bloch equations. Effective exchange
coupling (EC) and Dzyaloshinsky-Moriya interaction (DMI) parameters
between different neighbors Ji and di at different lattice constants were derived
by fitting the resulting spin spiral dispersion E(q) to EC model with DMI and E(q)-
E(-q) formula, respectively. We observed an increase in DMI and a significant
decrease in EC with an increase in strain. Hence, the size of Ne´ el-type skyrmions
determined by the ratio of EC/DMI can be controlled by applying strain, leading
to an effective approach to tailor the formation of skyrmion lattices by inducing
slight structural modifications on the magnetic thin films
