Isolated zero-field magnetic skyrmions in heterogeneous multilayer films stabilized by interlayer exchange coupling

Magnetic skyrmions are promising candidates for achieving low-power, next-generation synaptic computing due to their particle-like nature, strong coupling to electrical and spin currents, and room-temperature (RT) stability in multilayer films¹. However, in most homogeneous multilayers, the predominant magnetic textures at zero-field (ZF) are labyrinthine stripes². External applied magnetic field or geometric confinement³ are typically used to stabilize isolated skyrmions.

In this work, we design heterogeneous multilayers with two adjoining functional stacks with tunable interlayer exchange coupling (IEC)^4,5. Using magnetic force microscopy (MFM) and Lorentz transmission electron microscopy (LTEM), we investigate the evolution of magnetic textures with varying IEC as well as applied external field. Crucially, we show that isolated magnetic skyrmions could be stabilized within a finite IEC window. This work establishes and extends the use of IEC as a means of stabilizing ZF skyrmions and paves the path to skyrmion-based devices.

1. Fert, A. et al. Nat. Rev. Mater. 2, (2017).
2. Soumyanarayanan, A. et al. Nat. Mater. 16, (2017).
3. Ho, P. et al. Phys. Rev. Appl. 11, 024064 (2019).
4. Chen, G. et al. Appl. Phys. Lett. 106, 242404 (2015).
5. Legrand, W. et al. Nat. Mater. 1–9 (2019)