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The stability and resonance spectra associated with a domain wall skyrmion embedded within a Néel skyrmion, forming a 1-kink skyrmion, has been studied using micromagnetic simulations. We show that the 1-kink skyrmion is stable over a wide range of fields at moderate strengths of the Dzyaloshinskii-Moriya interaction. By exciting these structures with a broadband magnetic field excitation, we find complex resonance behavior deviating from that of a pure Néel skyrmion. For out-of-plane excitations, the 1-kink skyrmion demonstrates an additional mode relative to that of the Néel skyrmion at reduced amplitude. These consist of low frequency and high frequency modes associated with both a breathing mode and an oscillation of the embedded domain wall skyrmion. Following an in-plane excitation, both Néel and 1-kink skyrmions exhibit a counterclockwise rotational mode with similar frequencies, as well as a higher frequency mode associated with the interaction of the structure with the ferromagnetic background state. These results may help pave the way for exploration of more complex spin structures for magnetic-based microwave devices.
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Strain-mediated voltage-controlled switching of magnetic skyrmions in nanostructures
Abstract Magnetic skyrmions are swirling spin structures stabilized typically by the Dyzaloshinskii-Moriya interaction. The existing control of magnetic skyrmions has often relied on the use of an electric current, which may cause overheating in densely packed devices. Here we demonstrate, using phase-field simulations, that an isolated Néel skyrmion in a magnetic nanodisk can be repeatedly created and deleted by voltage-induced strains from a juxtaposed piezoelectric. Such a skyrmion switching is non-volatile, and consumes only ~0.5 fJ per switching which is about five orders of magnitude smaller than that by current-induced spin-transfer-torques. It is found that the strain-mediated skyrmion creation occurs through an intermediate vortex-like spin structure, and that the skyrmion deletion occurs though a homogenous shrinkage during which the Néel wall is temporarily transformed to a vortex-wall. These findings are expected to stimulate experimental research into strain-mediated voltage control of skyrmions, as well as other chiral spin structures for low-power spintronics.
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- Award ID(s):
- 1629270
- PAR ID:
- 10153899
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- npj Computational Materials
- Volume:
- 4
- Issue:
- 1
- ISSN:
- 2057-3960
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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