Abstract
The topological Hall effect (THE) is the Hall response to an emergent magnetic field, a manifestation of the skyrmion Berry-phase. As the magnitude of THE in magnetic multilayers is an open question, it is imperative to develop comprehensive understanding of skyrmions and other chiral textures, and their electrical fingerprint. Here, using Hall-transport and magnetic-imaging in a technologically viable multilayer film, we show that topological-Hall resistivity scales with the isolated-skyrmion density over a wide range of temperature and magnetic-field, confirming the impact of the skyrmion Berry-phase on electronic transport. While we establish qualitative agreement between the topological-Hall resistivity and the topological-charge density, our quantitative analysis shows much larger topological-Hall resistivity than the prevailing theory predicts for the observed skyrmion density. Our results are fundamental for the skyrmion-THE in multilayers, where interfacial interactions, multiband transport and non-adiabatic effects play an important role, and for skyrmion applications relying on THE.
Highlights
The topological Hall effect (THE) is the Hall response to an emergent magnetic field, a manifestation of the skyrmion Berry-phase
We use sputtered [Ir(1)/Fe(0.5)/Co(0.5)/ Pt(1)]20 multilayer films, with the composition chosen for exhibiting skyrmions across a large range of T
Using magnetic force microscopy (MFM) and transport measurements, we present a comprehensive picture of the evolution of magnetic textures and their THE signature in a multilayer film capable of hosting skyrmions from room temperature (RT) down to at least 5 K
Summary
As the applied field H is swept from saturation towards zero, we find that skyrmions aggregate in worm-like magnetic textures, which may carry large topological charge (QW), and manifest as peaks in ρTH. Quantitative modeling of these worm-textures uncovers qualitative agreement between. The dense textures at intermediate H (Fig. 1f–h, and Supplementary Figures 17 and 18) correspond to reduced, yet finite, Δρyx Careful inspection of such scans reveals worm-like features, to which we attribute the finite magnitude of Δρyx (Supplementary Note 7). The following analysis of the topological charge of worms is motivated by sequences like Fig. 1b–d [ in Supplementary Figures 17(n)–(o)], which suggest that worms result from skyrmions clustering as nsk increases. The energy barrier for this suggests that the effective topological charge should be at least equal to the total number of skyrmions that form a worm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
