The reported amplitude of the topological Hall effect for Néel skyrmions in thin film magnetic multilayers has varied widely between different research groups, with no obvious explanation. Our team has now identified the likely origin of these discrepancies: the topological Hall voltage is enormously enhanced by transverse charge scattering from chiral spin fluctuations at the phase boundary between isolated skyrmions and an ordered lattice. Writing in Nature Communications, we demonstrate that this fluctuation-induced Hall component follows the power-law scaling characteristic of second order phase transitions. Our results suggest that fine-tuning the skyrmion stability towards the critical point may boost the topological Hall signal by up to 4 orders of magnitude. This extreme sensitivity to thermal and magnetic control parameters may prove invaluable for developing logic and storage devices based on real-space spin topology.
Many thanks to our collaborators in Russia, Germany and Israel.
