Engineering skyrmions in transition-metal multilayers for spintronics

Magnetic skyrmions are localized, topologically protected spin structures that have been
proposed for storing or processing information due to their intriguing dynamical and transport
properties. Important in terms of applications is the recent discovery of interface stabilized
skyrmions as evidenced in ultra-thin transition-metal films. However, so far only skyrmions at
interfaces with a single atomic layer of a magnetic material were reported, which greatly
limits their potential for application in devices. Here we predict the emergence of skyrmions
in [4d/Fe2/5d]n multilayers, that is, structures composed of Fe biatomic layers sandwiched
between 4d and 5d transition-metal layers. In these composite structures, the exchange
and the Dzyaloshinskii–Moriya interactions that control skyrmion formation can be tuned
separately by the two interfaces. This allows engineering skyrmions as shown based on
density functional theory and spin dynamics simulations.