Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Spin structures have been a relevant topic of magnetism research for many years. In particular, magnetic vortices have attracted much at- tention, due to their non-trivial topology and the various dynamic modes they exhibit. A magnetic vortex consists of a planar, flux- closing magnetization curl that turns out of the plane in the central nanoscopic core. For a single layer structure, the curl’s radial components typically cancel each other out. Recent investigations show that this holds also true for multilayer vortex systems comprising bilinear interlayer exchange coupling (IEC). In this contribution we report on pairs of diverging-converging spin vortices occurring in biquadratically coupled systems. Using magnetic x-ray microscopy we directly observe that the individual vortices of such pairs possess a residual radial magnetization component. From this ∇M𝑥𝑦 ̸= 0, an additional perpendicular magnetization divergence ∇M𝑧 is analytically deduced. We compare our continuous model with discrete micromagnetic simulations.