Revealing Emergent Magnetic Charge in a Topological Antiferromagnet with Diamond Quantum Magnetometry

ORAL

Abstract

Whirling topological textures play a key role in exotic phases of magnetic materials and offer promise for logic and memory applications. In antiferromagnets, these textures exhibit enhanced stability and faster dynamics with respect to ferromagnetic counterparts, but they are also difficult to observe due to their vanishing net magnetic moment. Diamond quantum magnetometry offers a promising route to image such weak features through its high sensitivity and vectorial field detection. Here, we image the topological textures in the archetypal antiferromagnet, hematite, and reveal that these textures host in parallel a rich tapestry of monopolar, dipolar and quadrupolar magnetic charge distributions. By extracting field orientations, we demonstrate direct readout of the previously inaccessible antiferromagnetic vorticity, which is connected to magnetic charge through a duality relation. Our work highlights the critical role that diamond quantum magnetometry could play in exploring emergent phenomena and topological spintronics in quantum materials.

(A.T., H.J., M.H. contributed equally)

*Work at the University of Cambridge was supported by the Cambridge Nanoscale Sensing and Imaging Suite (CANSIS) as part of the Cambridge Henry Royce Institute under Engineering and Physical Sciences Research Council (EPSRC) grant No. EP/P024947/1. We acknowledge funding from EPSRC QUES2T (EP/N015118/1) and the Betty and Gordon Moore Foundation. Work done at the National University of Singapore was supported by the Agency for Science Technology Research (A*STAR) under Advanced Manufacturing Engineering Individual Research Grant (A1983c0034). Work done at the University of Oxford was supported by EPSRC grant (EP/M020517/1) and the Oxford-ShanghaiTech collaboration project. A.K.C.T. acknowledges funding from A*STAR, through the National Science Scholarship. H.J. acknowledges funding from Marie Sklodowska-Curie Postdoctoral Fellowship via UKRI Horizon Europe Guarantee (EP/X024938/1). M.H. acknowledges funding from EPSRC NQIT (EP/M013243/1). L.S. acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 101063285. H.S.K. acknowledges funding from the Royal Society through a University Research Fellowship.

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Publication: A manuscript on this work is currently under review.

Our previous related studies:
1. Jani, H. et al. Antiferromagnetic half-skyrmions and bimerons at room temperature. Nature 590, 74 (2021).
2. Jani, H., et al. Reversible hydrogen control of antiferromagnetic anisotropy in a-Fe2O3. Nature Communications 12, 1668 (2021).
3. Lim, Z. S.,* Jani, H.,* Venkatesan, T. & Ariando, A. Skyrmionics in correlated oxides. MRS Bulletin 46, 1053 (2021).

Presenters

  • Hariom Jani

    • University of Oxford

Authors

  • Hariom Jani

    • University of Oxford

  • Anthony Tan

    • Univ of Cambridge

  • Michael Hoegen

    • University of Cambridge

  • Lucio Stefan

    • Niels Bohr Institute

  • Claudio Castelnovo

    • Univ of Cambridge
    • University of Cambridge

  • Daniel Braund

    • University of Cambrdige

  • Alexandra Geim

    • University of Cambridge

  • Matthew Feuer

    • Univ of Cambridge

  • Helena S Knowles

    • University of Cambridge

  • Ariando Ariando

    • Natl Univ of Singapore

  • Paolo G Radaelli

    • University of Oxford

  • Mete Atatüre

    • Univ of Cambridge
    • University of Cambridge