  Magnetic skyrmions in chiral-lattice ferromagnets are currently attracting
enormous research interest because of their potential applications in
spintronic devices. However, they emerge in bulk specimens only in a narrow
window of temperature and magnetic field. This limited stability regime is
recognized as an obstacle to technical applications. Recent experiments
demonstrated that the thermodynamic stability of magnetic skyrmions is enhanced
or suppressed by the application of a uniaxial strain depending on its axial
direction in bulk chiral-lattice ferromagnets MnSi [Y. Nii et al., Nat. Commun.
6, 8539 (2015), A. Chacon et al., Phys. Rev. Lett. 115, 267202 (2015)] and
Cu2OSeO3 [S. Seki et al., Phys. Rev. B 96, 220404(R) (2017)]. Motivated by
these experimental discoveries, we theoretically investigated the effects of
anisotropic Dzyaloshinskii--Moriya interactions on the stability of magnetic
skyrmions caused by this uniaxial strain. We find that magnetic skyrmions are
significantly stabilized (destabilized) in the presence of anisotropic DM
interactions when an external magnetic field lies perpendicular (parallel) to
the anisotropy axis, along which the DM coupling is strengthened. Our results
account completely for the experimentally observed strain-induced stabilization
and destabilization of magnetic skyrmions and provide a firm ground for
possible strain engineering of skyrmion-based electronic devices.
