Creation and annihilation of non-volatile fixed magnetic skyrmions using voltage control of magnetic anisotropy

Abstract

Magnetic skyrmions are topological spin textures that could be used to create magnetic memory and logic devices. Such devices typically rely on current-controlled motion of skyrmions, but using skyrmions that are fixed in space could lead to more compact and energy-efficient devices. Here we report the manipulation of fixed magnetic skyrmions using voltage-controlled magnetic anisotropy. We show that skyrmions can be stabilized in antiferromagnet/ferromagnet/oxide heterostructure films without any external magnetic field due to an exchange bias field. The isolated skyrmions are annihilated or formed by applying voltage pulses that increase or decrease the perpendicular magnetic anisotropy, respectively. We also show that skyrmions can be created from chiral domains by increasing the perpendicular magnetic anisotropy of the system. Our experimental findings are corroborated using micromagnetic simulations.

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Fig. 1: Device structure and characterization.
Fig. 2: Current-driven skyrmion motion imaged using MOKE microscopy.
Fig. 3: VCMA-induced manipulation of skyrmions.
Fig. 4: Incomplete annihilation showing the stripe domain to skyrmion transformation.
Fig. 5: Micromagnetic simulation of the voltage control of skyrmions.

Data availability

MFM data files used in this paper are available at https://doi.org/10.6084/m9.figshare.12234446. Other data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request

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Acknowledgements

D.B. and J.A. are supported in part by NSF CAREER grant CCF-1253370, NSF CCF-1909030 and NSF ECCS 1609303, a VCU Quest Commercialization Grant and a Virginia Microelectronics Seed Grant. S.A.R., H.W., B.D. and K.L.W. are supported by the National Science Foundation (NSF) ECCS 1611570 and NSF Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS). The authors at UCLA are also supported by Spins and Heat in Nanoscale Electronic Systems (SHINES), an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under award no. SC0012670. The authors at UCLA were also partially sponsored by the Army Research Office under grant no. W911NF-16-1-0472.

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D.B., S.A.R., H.W., K.L.W. and J.A. played a role in conceiving the idea, planning the experiments, discussing the data, analysing the results and writing the manuscript. D.B. performed the MFM and micromagnetic simulations. S.A.R. performed other experimental characterization, H.W. fabricated the samples and B.D. performed MOKE. J.A. coordinated the overall project.

Corresponding authors

Correspondence to Kang L. Wang or Jayasimha Atulasimha.

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Supplementary Information

Supplementary Sections 1–6.

Supplementary Video

Skyrmions and stripe domains observed in the intermediate steps of switching during a cycle of perpendicular magnetic field.

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Bhattacharya, D., Razavi, S.A., Wu, H. et al. Creation and annihilation of non-volatile fixed magnetic skyrmions using voltage control of magnetic anisotropy. Nat Electron 3, 539–545 (2020). https://doi.org/10.1038/s41928-020-0432-x

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