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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.
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http://dx.doi.org/10.1038/s41467-018-08041-9 | DOI Listing |
Nano Lett
February 2025
Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China.
Topological magnetic materials are expected to show multiple transport responses because of their unusual bulk electronic topology in momentum space and their topological spin texture in real space. However, such multiple topological properties-hosting materials are rare in nature. In this work, we unambiguously reveal the emergence of magnetic skyrmions in MnGe single crystal through detailed electrical transport and Lorentz transmission electron microscopy (L-TEM) combined with calculations.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2025
School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata 700032, India.
Materials exhibiting topological transport properties, such as a large topological Hall resistivity, are crucial for next-generation spintronic devices. Here, we report large topological Hall resistivities in epitaxial supermalloy (NiFeMo) thin films with [100] and [111] orientations grown on single-crystal MgO (100) and AlO (0001) substrates, respectively. While X-ray reciprocal maps confirmed the epitaxial growth of the films, X-ray stress analyses revealed large residual strains in the films, inducing tetragonal distortions of the cubic NiFeMo unit cells.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
CMP Division, Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, Kolkata 700064, India.
-Mn-type chiral cubic CoZnMn(++= 20) alloys present a intriguing platform for exploring topological magnetic orderings with promising spintronic potential. This study examines the magnetotransport properties of CoRuZnMn, a skyrmion-hosting-Mn-type chiral compound. The longitudinal resistivity () exhibits field-insensitive low-temperature minima due to quantum interference effects, driven byT1/2-dependent electron-electron interactions.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Physics, University of Liverpool, Oxford Street, Liverpool, L69 7ZE, UK.
Topological semimetals have recently garnered widespread interest in the quantum materials research community due to their symmetry-protected surface states with dissipationless transport which have potential applications in next-generation low-power electronic devices. One such material, [Formula: see text], exhibits Dirac nodal arcs and although the topological properties of single crystals have been investigated, there have been no reports in crystalline thin film geometry. We examined the growth of [Formula: see text] heterostructures on a range of single crystals by optimizing the electron beam evaporation of Pt and Sn and studied the effect of vacuum thermal annealing on phase and crystallinity.
View Article and Find Full Text PDFAdv Mater
January 2025
Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany.
Colossal magnetoresistance (CMR) is an exotic phenomenon that allows for the efficient magnetic control of electrical resistivity and has attracted significant attention in condensed matter due to its potential for memory and spintronic applications. Heusler alloys are the subject of considerable interest in this context due to the electronic properties that result from the nontrivial band topology. Here, the observation of CMR near room temperature is reported in the shape memory Heusler alloy NiMnIn, which is attributed to the combined effects of magnetic field-induced martensite twin variant reorientation (MFIR) and magnetic field-induced structural phase transformation (MFIPT).
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