Low damping Co<sub>25</sub>Fe<sub>75</sub> devices for spin oscillator applications

ORAL

Abstract

Co25Fe75 films have garnered considerable attention due to their unique combination of ultralow damping, significant magnetostriction, and long spin-wave attenuation length while being metallic. These properties make them an ideal candidate for charge-based spintronic applications, including spin oscillators and hybrid phonon-magnon systems [1-2]. In this study, we synthesized CoFe films and nanostructures using DC magnetron sputtering and ebeam lithography. The resulting samples were characterized with ferromagnetic resonance (FMR), anisotropic magnetoresistance (AMR), spin torque-ferromagnetic resonance (ST-FMR), and magnetostriction measurements. We obtained low damping (αeff ~ 4.5 x 10-3) CoFe films and bilayers by optimizing seed layers, capping, composition, and deposition power. ST-FMR measurements of CoFe-Pt microwire devices demonstrated a significantly higher charge-to-spin conversion efficiency (~ 0.16), much larger than conventional Py-Pt devices (~ 0.05) of identical structure. These results suggest that Co25Fe75 is highly promising for spin oscillator and magnonic applications.

[1] A. J. Lee, J. T. Brangham, Y. Cheng, S. P. White, W. T. Ruane, B. D. Esser, D. W. McComb, P. C. Hammel, and F. Yang, Nat. Comm. 8, 234 (2017).

[2] D. Schwienbacher, M. Pernpeintner, L. Liensberger, E. R. J. Edwards, H. T. Nembach, J. M. Shaw, M. Weiler, R. Gross, and H. Huebl, Journal of Applied Physics 126, 103902 (2019).

*This research was supported by the Quantum Materials for Energy Efficient Neuromorphic Computing (Q-MEEN-C), an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES). The nanostructures were realized at the Advanced Science Research Center NanoFabrication Facility of the Graduate Center at the City University of New York.

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Presenters

  • Padma Radhakrishnnan

    • New York University (NYU)

Authors

  • Padma Radhakrishnnan

    • New York University (NYU)

  • Tian-Yue Chen

    • New York University (NYU)

  • Zhixin Zhang

    • University of Illinois at Urbana-Champaign

  • Robin Klause

    • University of Illinois at Urbana-Champaign

  • Axel F Hoffmann

    • University of Illinois at Urbana-Champaign
    • UIUC

  • Eric E Fullerton

    • University of California, San Diego

  • Andrew D Kent

    • New York University (NYU)
    • Center for Quantum Phenomena, Department of Physics, New York University, New York, 10003, USA