The evolution of skyrmions in Ir/Fe/Co/Pt multilayers and their topological Hall signature:
Using Hall transport and magnetic imaging, we track the evolution of chiral magnetic textures and their topological Hall effect signature in a multilayer film. We show that topological Hall resistivity scales with the density of isolated skyrmions (n_sk) over a wide range of temperature, confirming the impact of the skyrmion Berry-phase on electronic transport. Furthermore, we find that at higher n_sk skyrmions cluster into worms, which carry considerable topological charge, unlike topologically-trivial spin spirals.
