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Experimental observation of magnetic hopfions in multilayer disks

ORAL

Abstract

Topological solitons are currently of high interest to condensed matter physics. Among those, magnetic skyrmions (Sk) are two-dimensional objects with a continuous winding of the magnetization, and magnetic Hopfions are 3D topological solitons that can be formed from a closed loop of a twisted skyrmion string. Whereas intense research with magnetic Sks has already led to a deep understanding and potential applications in advanced storage and logic devices1,2, the experimental validation of magnetic Hopfions has been elusive so far. Theoretical models suggest that Hopfions can be stabilized in frustrated or chiral magnetic systems, and kπ skyrmions, aka target skymions (TSk) can be transformed into Hopfions by adapting their perpendicular magnetic anisotropy3,4.
We present experimental evidence of magnetic Hopfions in magnetic Ir/Co/Pt multilayers shaped into nanoscale disks, which are known to host TSks5. Their distinct 3D spin texture was observed by combining two magnetic soft x-ray microscopies, namely surface sensitive X-PEEM, and bulk sensitive full field MTXM.
1 A. Fert,et al, Nat. Nanotech. 8 152 (2013)
2 A. Soumyanarayanan, et al. Nat. Mat. 16 898 (2017)
3 P. Sutcliffe, JPhysA (2018)
4 Y. Liu et al PRB 98 174437 (2018)
5 N. Kent et al. APL 115 112404 (2019)

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Presenters

  • Peter Fischer

    Lawrence Berkeley National Laboratory, University of California, Santa Cruz

Authors

  • Noah Kent

    Lawrence Berkeley National Laboratory

  • Neal Reynolds

    Lawrence Berkeley National Laboratory

  • David Raftrey

    University of California, Santa Cruz, Lawrence Berkeley National Laboratory

  • Ian T.G. Campbell

    Lawrence Berkeley National Laboratory

  • Selven Virasawmy

    Lawrence Berkeley National Laboratory

  • Scott Dhuey

    Lawrence Berkeley National Laboratory

  • Rajesh V Chopdekar

    Advanced Light Source, Lawrence Berkeley National Lab, University of California, Davis, Lawrence Berkeley National Laboratory

  • Aurelio Hierro-Rodriguez

    University of Oviedo, Spain, University Oviedo

  • Andrea Sorrentino

    ALBA Synchrotron, Spain, ALBA Synchrotron

  • Eva Pereiro

    ALBA Synchrotron, Spain, ALBA Synchrotron

  • Salvador Ferrer

    ALBA Synchrotron, Spain, ALBA Synchrotron

  • Frances Hellman

    Physics, University of California, Berkeley, Lawrence Berkeley National Laboratory, University of California Berkeley

  • Paul M. Sutcliffe

    U Durham

  • Peter Fischer

    Lawrence Berkeley National Laboratory, University of California, Santa Cruz