Freezing and thawing magnetic droplet solitons

ORAL

Abstract

We use all-perpendicular nanocontact spin-torque oscillators to study the low-field behavior of magnetic droplets. These dissipative solitons are inherently dynamic and are characterized by a core of reversed spins surrounded by a precessing perimeter [1, 2, 3, 4]. The precession frequency lies between the ferromagnetic and Zeeman resonances, but the droplet is also prone to drift which gives additional dynamics [5, 6]. Electrical measurements reveal that the droplet transforms, freezes, into a static bubble at low fields. Once formed, the bubble is stable without a sustaining current. Furthermore, the droplet-to-bubble transition is fully reversible and the bubble can thaw back to a droplet at sufficient high field and current. The findings are corroborated by X-ray microscopy, which images the magnetic states during the freezing. Experimental data together with simulations identify pinning as the main mechanism behind the bubble stability.

 

[1] Hoefer et al., PRB 82, 054432 (2010)

[2] Mohseni et al., Science 339, 1295 (2013)

[3] Chung et al., J. Appl. Phys 115, 172612 (2014)

[4] Chung et al., PRL 120, 217204 (2018)

[5] Xiao et al., PRB 95, 024106 (2017)

[6] Chung et al, Nat. Com. 7, 11209 (2016)

*This work was supported by the Swedish Research Council (VR; 2017-06711 and 2019-04229). Helmholtz Zentrum Berlin is acknowledged for allocating beam time at the BESSY II synchrotron radiation facility. M. W., E.G., G.S. and J.G. acknowledge the financial support by the Federal Ministry of Education and Research of Germany in the frame work of DynaMAX (Project No. 05K18EYA). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIT) (No. 2020R1F1A1049642)

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Publication: Freezing and thawing magnetic droplet solitons, arXiv:2104.14897
Freezing and thawing magnetic droplet solitons (submitted to Nature Communications)

Presenters

  • Martina Ahlberg

    • University of Gothenburg

Authors

  • Martina Ahlberg

    • University of Gothenburg

  • Sunjae Chung

    • Korea National University of Education

  • Sheng Jiang

    • University of Gothenburg

  • Q. Tuan Le

    • KTH Royal Institute of Technology

  • Roman Khymyn

    • University of Gothenburg, Sweden
    • University of Gothenburg
    • Physics Department, University of Gothenburg
    • Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden

  • Hamid Mazraati

    • KTH Royal Institute of Technology

  • Markus Weigand

    • Helmholtz Center Berlin
    • Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
    • Helmholtz-Zentrum Berlin für Materialien und Energie
    • Max Planck Institute for Intelligent Systems

  • Iuliia Bykova

    • Max Planck Institute for Intelligent Systems

  • Felix Groß

    • Max Planck Institute for Intelligent Systems

  • Eberhard Goering

    • Max Planck Institute for Intelligent Systems

  • Gisela Schütz

    • Max-Planck-Institute for Intelligent Systems, 70569 Stuttgart, Germany
    • Max Planck Institute for Intelligent Systems

  • Joachim Gräfe

    • Max Planck Institute for Intelligent Systems

  • Johan Åkerman

    • Goteborg Univ
    • University of Gothenburg
    • 1Physics Department, University of Gothenburg, 41296 Gothenburg, Sweden.
    • University of Gothenburg, Sweden
    • Physics Department, University of Gothenburg
    • Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden