Three-dimensional skyrmionic cocoons in magnetic multilayers

Three-dimensional spin textures emerge as promising quasi-particles for encoding information in future spintronic devices. The third dimension provides more malleability regarding their properties and more flexibility for potential applications. However, the stabilization and characterization of such quasi-particles in easily implementable systems remain a work in progress. Here we observe a three-dimensional magnetic texture that sits in the interior of magnetic thin films aperiodic multilayers and possesses a characteristic ellipsoidal shape. Interestingly, these objects that we call skyrmionic cocoons can coexist with more standard tubular skyrmions going through all the multilayer as evidenced by the existence of two very different contrasts in room temperature magnetic force microscopy. The presence of these novel skyrmionic textures as well as the understanding of their layer resolved chiral and topological properties have been investigated by micromagnetic simulations. Finally, we show that the skyrmionic cocoons can be electrically detected using magneto-transport measurements. Three dimensional topological spin textures, such as hopfions and skyrmion tubes, have seen a surge of interest for their potential technological applications. They offer greater flexibility than their two dimensional counterparts, but have been hampered by the limited material platforms. Here, Grelier et al. look at aperiodic multilayers, and observe a three dimensional skyrmionic cocoon.

Automated summary

Three-dimensional spin textures, including skyrmion cocoons, have been observed in aperiodic multilayers and can coexist with standard tube-like skyrmions. These novel textures have potential technological applications and can be electrically detected using magneto-transport measurements.