Thickness tunable zoology of magnetic spin textures observed in Fe<sub>5</sub>GeTe<sub>2</sub>

ORAL

Abstract

Two-dimensional van der Waals (vdW) materials offer avenues to modulate structure and magnetic interactions. In this context, Fe₅GeTe₂ (FGT5), a ferromagnetic compound, stands out. Using a laboratory x-ray source, we reveal the predominant (1×1) FGT5 phase, previously assumed centrosymmetric, lacks inversion symmetry. We also identify a minority phase with a (√3×√3)-R30° superstructure, distinctively two-dimensional, originating from ordered Te-vacancies in the top FGT5 layers.

Real-space magnetic imaging showcases three magnetic states in FGT5 lamellae, varying with thickness: a multi-domain state, a stripe phase, and an uncharted fractal state. The stripe phase houses unconventional type-I and type-II bubbles with non-uniform core spin textures. In thicker FGT5 (~170 µm), a magnetic field induces a 'bobber' or 'cocoon' spin texture stemming from the fractal state.

FGT5's varied magnetic phases make it a captivating subject in the study of 2D vdW magnetic interactions.

*We acknowledge funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement SORBET No 670166). We also acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project number 403505322, Priority Program SPP2137 and project no. 443406107 under the Priority Program (SPP) 2244. Funding by the International Max Planck Research School for Science and Technology of Nano-Systems is also gratefully acknowledged.

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Publication: Journal: ACS Nano
Manuscript ID: nn-2023-09602j
Title: "Thickness tunable zoology of magnetic spin textures observed in Fe5GeTe2"

Presenters

  • Ajesh Kollakuzhiyil Gopi

    • Max Plank Institute of Microstructure Physics

Authors

  • Ajesh Kollakuzhiyil Gopi

    • Max Plank Institute of Microstructure Physics

  • Abhay Kant Srivastava

    • Max Planck Institute of Microstructure Physics

  • Ankit Kumar Sharma

    • Max Planck Institute of Microstructure Physics

  • Souvik Das

    • Max Planck Institute of Microstructure Physics

  • Hakan Deniz

    • Max Planck Institute of Microstructure Physics

  • Arthur Ernst

    • Johannes Kepler University, Altenbergerstraβe 69, Linz 4040, Austria
    • Johannes Kepler University Linz
    • Max Planck Institute of Microstructure Physics

  • Binoy Krishna K Hazra

    • Max Planck Institute of Microstructure Physics

  • Holger L Meyerheim

    • Max Plank Institute of Microstructure Physics
    • MPI of Microstructure Physics

  • Anirban Chakraborty

    • max planck institute of microstructure physics

  • Stuart S Parkin

    • Max Planck Institute of Microstructure Physics