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Magnetic Imaging of Antiferromagnetic Domain Walls in Magnetic Topological Materials

ORAL

Abstract

The study and control of domains and domain walls (DW) in topological materials is crucial to understanding and utilizing their exotic phenomena, such as axion insulator and quantum anomalous Hall states1-3. Domains of alternating sign in these materials cancel out these states and thus it is imperative to understand how these antiferromagnetic (AFM) domains form and can be controlled. Despite many efforts, it has been challenging to directly visualize AFM domains or DWs with nanoscale resolution in general, especially in magnetic field. Here, we report the magnetic imaging of domains and DWs in several uniaxial AFMs, the topological insulator MnBi2Te4 family4 and the topological semimetal EuMnBi25, using cryogenic magnetic force microscopy (MFM)6. Our MFM results reveal higher magnetic susceptibility or net moments inside the DWs than in domains. DWs in these AFMs form randomly with strong thermal and magnetic field dependences.

1 Otrokov, M. M. et al. PRL. 122, 107202 (2019).
2 Deng, Y. et al. arXiv:1904.11468 (2019).
3 Liu, C. et al. arXiv:1905.00715 (2019).
4 Yan, J., -Q.. et al. PRB 100, 104409 (2019).
5 Masuda, H. et al. Sci. Adv. 2, 1–7 (2016).
6 Sass, P. M. et al. arXiv:1910.06488 (2019).

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Presenters

  • Paul Sass

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick

Authors

  • Paul Sass

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick

  • Wenbo Ge

    Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick

  • Weida Wu

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Department of Physics and Astronomy, Rutgers University, New Brunswick, Rutgers University, New Brunswick

  • Jiaqiang Yan

    Materials Science and Engineering, The University of Tennessee, Oak Ridge National Lab, Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • Dimuthu Obeysekera

    Physics, Central Michigan University, Department of Physics, New Jersey Institute of Technology, Central Michigan University

  • Junjie Yang

    Physics, New Jersey Institute of Technology, Department of Physics, New Jersey Institute of Technology, New Jersey Institute of Technology, Physics, Central Michigan University, Central Michigan University