Controlling Dzyaloshinskii-Moriya Interaction via Chirality Dependent   Layer Stacking, Insulator Capping and Electric Field
  Using first-principle calculations, we demonstrate several approaches to manipulate Dzyaloshinskii-Moriya Interaction (DMI) in ultrathin magnetic films. First, we find that DMI is significantly enhanced when the ferromagnetic (FM) layer is sandwiched between nonmagnetic (NM) layers inducing additive DMI in NM/FM/NM structures. For instance, as Pt and Ir below Co induce DMI of opposite chirality, inserting Co between Pt (below) and Ir (above) in Ir/Co/Pt trilayers enhances the DMI of Co/Pt bilayers by 15\%. Furthermore, in case of Pb/Co/Pt trilayers (Ir/Fe/Co/Pt multilayers), DMI can be enhanced by 50\% (almost doubled) compared to Co/Pt bilayers reaching a very large DMI amplitude of 2.7 (3.2) meV/atom. Our second approach for enhancing DMI is to use oxide capping layer. We show that DMI is enhanced by 60\% in Oxide/Co/Pt structures compared to Co/Pt bilayers. Moreover, we unveiled the DMI mechanism at Oxide/Co inerface due to interfacial electric field effect, which is different to Fert-Levy DMI at FM/NM interfaces. Finally, we demonstrate that DMI amplitude can be modulated using an electric field with efficiency factor comparable to that of the electric field control of perpendicular magnetic anisotropy in transition metal/oxide interfaces. These approaches of DMI controlling pave the way for skyrmions and domain wall motion-based spintronic applications. 
Hongxin Yang, Olivier Boulle, Vincent Cros, Albert Fert, and Mairbek   Chshiev
cond-mat.mtrl-sci cond-mat.mes-hall