Correlating Induced Magnetization and the Dyzaloshinskii-Moriya Interaction in Skyrmion-host Metallic Multilayers*

In metallic multilayers, skyrmions can form at interfaces between a 3d elemental ferromagnet (e.g., Co, Fe) and a 5d nonmagnetic element (e.g., Ir, Pd), where broken inversion symmetry and large spin-orbit coupling enable Dzyaloshinskii-Moriya interactions (DMI) to generate chiral magnetic structures. Skyrmions in these systems can be moved through the material by small spin currents and thus present a promising opportunity to realize new, low-energy magnetic storage technologies. Here, we examine prototypical Pt/Co/Pt and Pt/Co/Ir heterostructures to address the question of how the strength of the net DMI of a multilayer structure corresponds to the strength of the proximity-induced magnetism (PIM) that exists in the Stoner-susceptible 5d metals. Specifically, we compare DMI strength, as measured by the spin-orbit torque induced effective field under an in-plane bias magnetic field, to the magnitude of the PIM in Pt and Ir, as determined by X-ray magnetic circular dichroism. We also use resonant reflectometry at the Pt and Ir L₃ edges to extract magnetic depth profiles to understand how PIM changes as a function of Pt and Ir layer thickness.