Strain-dependent Dzyaloshinskii-Moriya interaction in a ferromagnet/heavy-metal bilayer
O. G. Udalov, I. S. Beloborodov
Abstract
We study the dependence of the Dzyaloshinskii-Moria interaction (DMI) using the $s\text{\ensuremath{-}}d$ model in the bilayer ferromagnet/heavy-metal system on the mechanical strain applied to the system. We show that DMI is sensitive to the strain perpendicular to the film plane. It can vary 40% under the strain of 0.3%. Such a strong variation is in agreement with recent experiment [Phys. Rev. Lett. 124, 157202 (2020)]. The DMI coefficient variation is mostly related to the change of the distance between heavy-metal atomic planes under the strain. Changing the in-plane distance between the heavy-metal ions does not produce strong variation of DMI. Anisotropy of the DMI interaction may appear if the strain is anisotropic in the plane of the bilayer. The DMI anisotropy is related to the anisotropy of the electron effective mass in the film plane induced by the strain.