Advanced Light Source Lawrence Berkeley National Laboratory
Shining x-rays on topological magnetic texture: Insight into skyrmions
Recently discovered skyrmions present an example of a topological phase that manifests in magnetic systems as a hexagonal lattice of spin vortices. Skyrmions can be moved coherently over macroscopic distances with very low currents, and are therefore a potential candidate for low power storage and logic application. In this talk I will show that x-ray based techniques are a powerful way to study these exotic phases.
I will discuss our observation of skyrmions using resonant soft x-ray scattering in multiferroic Cu 2 SeO 3 , and demonstrate the unexpected existence of two distinct skyrmion sub-lattices that arise from inequivalent Cu sites with chemically identical coordination numbers and valency. We have also studied skyrmion spin texture in an ultra-thin FeGd multilayer that shows perpendicular anisotropy. The FeGd sample exhibits a near perfect aligned stripe phase, and within a small range of temperature and magnetic field we observe a hexagonal scattering pattern due to a skyrmion lattice. I will also show the effect of optical impulses on the skyrmions, and the evolution of spontaneous fluctuations as the system enters a skyrmion lattice phase.
This work is funded by U.S. DOE.