Ferromagnetic Resonance Spectroscopy, Micromagnetic Simulations and Scanning Transmission X-ray Microscopy as a toolbox for the characterization of magnetic nanoparticle ensembles

POSTER

Abstract

Magnetic nanoparticles are studied for applications from medical research towards high performance computing using magnonic excitations. [1-3]. The understanding of their dynamic magnetic properties is a crucial task to bring such particle ensembles towards the application state. A characterization toolbox for these demands is the combination of Ferromagnetic Resonance (FMR) spectroscopy, micromagnetic simulations and element-specific (Time-Resolved) Scanning Transmission X-ray Microscopy (TR-STXM) [4][5], using X-ray Circular Magnetic Dichroism (XMCD) as contrast mechanism [6]. Here we present the use of this toolbox for the dynamic magnetic characterization of Fe3O4 nanoparticles ensembles naturally grown by biomineralization within magnetotactic bacteria of the species Magnetospirillum Magnetotacticum (average particle diameter 40 to 50 nm). In-plane angular dependent X-band FMR spectroscopy shows a multitude of angular dependent resonances exhibiting magnonic band gaps and crossings, well resembled by micromagnetic simulations. With TR-STXM we demonstrate the phase resolved sampling of magnetization dynamics of a nanoparticle ensemble of the same species showing a resonant response uniform in phase and non-uniform in amplitude with < 50 nm spatial resolution supplemented by micromagnetic simulations in good agreement [4].

References

[1] V.V. Kruglyak, S.O. Demokritov, et al. Journal of Physics D: Applied Physics, 2010. 43(26).

[2] A. Hoffmann and S.D. Bader. Physical Review Applied, 2015. 4(4): p. 047001-1-047001-18.

[3] B. Zingsem, T. Feggeler, et al. Nature Communications, 2019. 10: p. 4345.

[4] T. Feggeler, R. Meckenstock, et al. Physical Review Research, 2021. 3(3).

[5] S. Bonetti, R. Kukreja, et al. Review of Scientific Instruments, 2015. 86(9): p. 093703-1-093703-9.

[6] J. Stöhr and H.C. Siegmann, Magnetism From Fundamentals to Nanoscale Dynamics. Springer, ed. M. Cardona, et al. 2006, Berlin, Heidelberg: Springer.

*Lawrence Berkeley National Laboratory is acknowledged for funding through LDRD Award: Development of a Continuous Photon Counting Scheme for Time Resolved Studies. We thank the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project No. OL513/1-1, 321560838 and Project-ID 405553726 TRR 270 for financial funding.

Publication: [3] B. Zingsem, T. Feggeler, et al. Nature Communications, 2019. 10: p. 4345.
[4] T. Feggeler, R. Meckenstock, et al. Physical Review Research, 2021. 3(3).

Presenters

  • Thomas Feggeler

    • Lawrence Berkeley National Laboratory

Authors

  • Thomas Feggeler

    • Lawrence Berkeley National Laboratory

  • Ralf Meckenstock

    • University of Duisburg-Essen

  • Detlef Spoddig

    • University of Duisburg-Essen

  • Benjamin Zingsem

    • University of Duisburg-Essen

  • Johanna Lill

    • University of Duisburg-Essen

  • Damian Günzing

    • University of Duisburg-Essen

  • Sebastian Wintz

    • Max Planck Institute for Intelligent Systems

  • Markus Weigand

    • Helmholtz Center Berlin

  • Michael Winklhofer

    • University of Oldenburg

  • Michael Farle

    • University of Duisburg-Essen

  • Heiko Wende

    • University of Duisburg-Essen

  • Katharina Ollefs

    • University of Duisburg-Essen

  • Hendrik Ohldag

    • Lawrence Berkeley National Laboratory