Tuning the Size of Skyrmion by Strain at the Co/Pt 3 Interfaces

Based on density functional theory calculations, we elucidated the tunability of the atomic and magnetic structures of Co/Pt3 interface and thus the skyrmion sizes using strain. The dispersion relations of spin spiral at opposite direction 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 magnon dispersion E(q) to EC model with DMI and E(q)-E(-q) formula, respectively. We observed that DMI increases and EC decreases significantly with strain. Hence, the size of Neel-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.