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Magnetic vortex cores as tunable spin-wave emitters

Nature Nanotechnology volume 11, pages 948–953 (2016)Cite this article

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Abstract

The use of spin waves as information carriers in spintronic devices can substantially reduce energy losses by eliminating the ohmic heating associated with electron transport. Yet, the excitation of short-wavelength spin waves in nanoscale magnetic systems remains a significant challenge. Here, we propose a method for their coherent generation in a heterostructure composed of antiferromagnetically coupled magnetic layers. The driven dynamics of naturally formed nanosized stacked pairs of magnetic vortex cores is used to achieve this aim. The resulting spin-wave propagation is directly imaged by time-resolved scanning transmission X-ray microscopy. We show that the dipole-exchange spin waves excited in this system have a linear, non-reciprocal dispersion and that their wavelength can be tuned by changing the driving frequency.

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Figure 1: Schematics of a spin wave propagating along ek.
Figure 2: Sketches and scanning transmission X-ray microscopy images of magnetic vortices.
Figure 3: Time-resolved scanning transmission X-ray microscopy images of spin-wave emission from magnetic vortex cores (sample 1).
Figure 4: Dispersion f(k) of collective spin waves propagating perpendicular to the direction of static magnetization in a trilayer where two in-plane ferromagnetic layers are antiferromagnetically coupled via a non-magnetic interlayer.
Figure 5: Pulsed excitation of spin waves in the two samples containing magnetic vortex pairs with opposite circulations.

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Acknowledgements

The authors thank A. Puzic, K.W. Chou and M.-Y. Im for their contributions to the preparation of this work, C. Quitmann, H. Stoll, G. Schütz, M. Curcic, R. Mattheis, J. McCord, S. Gemming, V. Sluka, K. Schultheiss and R. Hübner for their support and discussions, as well as V. Kühn, J. Kerbusch and K. Kirsch for their assistance in sample fabrication. Most experiments were performed at the Maxymus endstation at BESSY2, HZB (Berlin, Germany). The authors acknowledge HZB for the allocation of synchrotron radiation beam time. Some experiments were performed at the Pollux endstation at SLS, PSI (Villigen, Switzerland). Pollux is financed by BMBF under contracts nos. 05KS4WE1/6 and 05KS7WE1. Technical support by M. Bechtel and B. Sarafimov at the scanning transmission X-ray microscopy set-ups is gratefully acknowledged. This work was supported in part (V.T. and A.S.) by a grant from DARPA MTO/MESO (nos. N66001-11-1-4114), grant no. ECCS-1305586 from the National Science Foundation, and by contracts from the US Army TARDEC, RDECOM. V.T. and A.S. acknowledge the Center for NanoFerroic Devices (CNFD) and the Nanoelectronics Research Initiative (NRI) for partial support of this work.

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Authors and Affiliations

  1. Helmholtz-Zentrum Dresden-Rossendorf, Dresden, 01328, Germany

    Sebastian Wintz, Jürgen Lindner, Artur Erbe & Jürgen Fassbender

  2. Technische Universität Dresden, Dresden, 01069, Germany

    Sebastian Wintz & Jürgen Fassbender

  3. Oakland University, Rochester, 48309, Michigan, USA

    Vasil Tiberkevich & Andrei Slavin

  4. Max-Planck-Institut für Intelligente Systeme, Stuttgart, 70569, Germany

    Markus Weigand

  5. Paul Scherrer Institut, Villigen, 5232, Switzerland

    Jörg Raabe

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Contributions

S.W., M.W. and J.R. performed the experiments. S.W. fabricated the samples and performed the simulations. V.T. and A.S. calculated the dispersion relations. S.W. and A.S. wrote the manuscript. All authors discussed the data and commented on the manuscript.

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Wintz, S., Tiberkevich, V., Weigand, M. et al. Magnetic vortex cores as tunable spin-wave emitters. Nature Nanotech 11, 948–953 (2016). https://doi.org/10.1038/nnano.2016.117

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