|
Magnetic skyrmions are magnetic textures, topologically different from the uniform ferromagnetic state, holding a lot of promise for applications as well as of fundamental interest. They have been observed in magnetic multilayers at room temperature only a couple of years ago [1]. In magnetic multilayers, a key to stabilize magnetic skyrmions is the Dzyaloshinskii-Moriya interaction, obtained at the interfaces between ferromagnetic layers and heavy-metal/oxides spacers, which promotes a unique chirality of the skyrmionic spin textures. Combined with spin-orbit torques generated in heavy-metal layers, this unique chirality allows very efficient current-induced motion at speeds reaching 100m/s [2].
In this presentation, we report about our predictions and observations of hybrid chirality in skyrmionic systems, arising from a competition between the Dzyaloshinskii-Moriya interaction and the other magnetic interactions. After having demonstrated a direct evidence of such hybrid chirality [3] by probing the surface spin ordering of multilayers with circular dichroism in X-ray resonant magnetic scattering [4], we will discuss the impact of hybrid chirality in technologically relevant multilayers depending on different parameters such as the number of stacked layers, interfacial anisotropy or interlayer exchange coupling. In the perspective of technological applications of skyrmions, controlling their chirality to match the spin-orbit torques injection geometry of the multilayers is required to achieve efficient current-induced motion.
[1] C. Moreau-Luchaire et al, Nat. Nano. 11, 444 (2016).
[2] A. Hrabec et al, Nat. Comm. 8, 15765 (2017).
[3] W. Legrand et al, arXiv:1712.05978v2 (2017).
[4] J.-Y. Chaleau et al, Phys. Rev. Lett. 120, 037202 (2018).
|
