Non-collinear magnetism and zero-field skyrmions in all-light-metal multilayers

 · Invited

Abstract

Magnetic skyrmions [1] are at the core of many recently proposed spintronic devices. Most of the thin film multilayers hosting magnetic skyrmions [2-3] are characterized by [heavy metals]\ferromagnet interfaces to generate a strong Dzyaloshinskii-Moriya interaction (DMI) and usually an external magnetic field is needed to stabilize the skyrmions. From an application point of view, both the use of heavy metals (rare and expensive) and the need for an external magnetic field (incompatible with nanoelectronics due to scalability issues) are limitations. Accordingly, it is highly desirable to have [light metal]-based systems capable of hosting skyrmions at zero field.
Here, I will first discuss the observation of magnetic domain walls with uni-directional sense of rotation in [light-metal]\ferromagnet multilayers. Density functional theory calculations allows us to understand the origin and predict the strength of the DMI in those systems, which compares well with experimental values. Subsequently, I will discuss how such systems can be employed for the stabilization of isolated magnetic skyrmions at room temperature and zero magnetic field via interlayer exchange coupling (IEC) [4,5]. By carefully adjusting the IEC in the system we can tune the size of the observed skyrmions. Those findings open up the possibility to develop cost-effective skyrmion-based spintronic devices suitable for general-user applications which go beyond modern nanoelectronics.

[1] N. Romming et al., Science 341, 636 (2013).
[2] C. Moreau-Luchaire et al., Nat. Nanotechnol. 11, 444 (2016).
[3] A. Soumyanarayanan et al., Nat. Mater. 16, 898 (2017).
[4] G. Chen et al., Appl. Phys. Lett. 106, 242404 (2015).
[5] R. Lo Conte et al., Nano Lett. 20, 4739 (2020).

*EU Marie Curie Fellow (748006-SKDWONTRACK); ARPA-E (DE-AR0000664); US DoE Early Career Research Program; US NSF (DMR-1610060, DMR-1905468, DMR-1828420); UCOP (MRP-17-454963); Department of Atomic Energy, Government of India; US DoE (DE-AC02-05CH11231)

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Presenters

  • Roberto Lo Conte

    • University of Hamburg
    • Department of Physics, University of Hamburg, Hamburg, Germany

Authors

  • Roberto Lo Conte

    • University of Hamburg
    • Department of Physics, University of Hamburg, Hamburg, Germany

  • Ashis K. Nandy

    • School of Physical Sciences, National Institute of Science Education and Research, HBNI, P.O. Jatni, 752050, India

  • Gong Chen

    • Georgetown University
    • Physics Department, Georgetown University, Washington, DC, USA

  • Andre L. Fernandes Cauduro

    • National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Ajanta Maity

    • School of Physical Sciences, National Institute of Science Education and Research, HBNI, P.O. Jatni, 752050, India

  • Colin Ophus

    • Molecular Foundry, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • LBNL
    • National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Zhijie Chen

    • Physics Department, Georgetown University, Washington, DC, USA

  • Alpha N'Diaye

    • Advanced Light Source
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley Laboratory, E O Lawrence Berkeley National Laboratory, Berkeley, CA, US, academic/govt
    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Hongxin Yang

    • Ningbo Institute of Materials Technology and Engineering, CAS, Ningbo, China

  • Kai Liu

    • Georgetown University
    • Physics Department, Georgetown University, Washington, DC, USA

  • Andreas Schmid

    • Lawrence Berkeley National Laboratory
    • National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Roland Wiesendanger

    • University of Hamburg
    • Department of Physics, University of Hamburg, Hamburg, Germany