  To stabilize the non-trivial spin textures, e.g., skyrmions or chiral domain
walls in ultrathin magnetic films, an additional degree of freedom such as the
interfacial Dzyaloshinskii-Moriya interaction (IDMI) must be induced by the
strong spin-orbit coupling (SOC) of a stacked heavy metal layer. However,
advanced approaches to simultaneously control IDMI and perpendicular magnetic
anisotropy (PMA) are needed for future spin-orbitronic device implementations.
Here, we show an effect of atomic-scale surface modulation on the magnetic
properties and IDMI in ultrathin films composed of 5d heavy
metal/ferromagnet/4d(5d) heavy metal or oxide interfaces, such as
Pt/CoFeSiB/Ru, Pt/CoFeSiB/Ta, and Pt/CoFeSiB/MgO. The maximum IDMI value
corresponds to the correlated roughness of the bottom and top interfaces of the
ferromagnetic layer. The proposed approach for significant enhancement of PMA
and IDMI through the interface roughness engineering at the atomic scale offers
a powerful tool for the development of the spin-orbitronic devices with the
precise and reliable controllability of their functionality.
