Universal current-velocity relation of skyrmion motion in chiral magnets
By J. Iwasaki, M. Mochizuki, N. Nagaosa. Nature Communications, 2012
628 citations recorded by the source corpus.
Current-driven motion of the magnetic domain wall in ferromagnets is attracting intense attention because of potential applications such as racetrack memory. There, the critical current density to drive the motion is ~109–1012 A m−2. The skyrmions recently discovered in chiral magnets have much smaller critical current density of ~105–106 A m−2, but the microscopic mechanism is not yet explored. Here we present a numerical simulation of Landau–Lifshitz–Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the skyrmion motion driven by the spin-transfer-torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix. Simulation results are analysed using a theory based on Thiele’s equation, and it is concluded that this behaviour is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal, which enable them to avoid pinning centres. Current-induced motion of skyrmions is attracting attention due to its low critical current density, however, its microscopic mechanisms have not been elucidated yet. Using numerical simulations, the authors demonstrate a universal current-velocity relation of skyrmion motion, independent of disorder or nonadiabatic effects.
Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
View Paper: https://www.semanticscholar.org/paper/0ec152aa647fbde8438f8e724af0ee35bee7e825
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Citations in the corpus
- Ginzburg-Landau theory for skyrmions in inversion-symmetric magnets with competing interactions (2015, background): “[51] Junichi Iwasaki, Masahito Mochizuki, and Naoto Nagaosa, “Universal current-velocity relation of skyrmion motion in chiral magnets,” Nature Communications 4, 1463 (2013).”
- Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. (2013, methodology): “tOOP = −j u t (m × mP) (6) where t is the film thickness and j is the amplitude of the out-of-plane torque relative to the in-plane one and mP is the current polarization vector.”
- Skyrmions in magnetic multilayers (2017, background): “facilitated by transfer of the spin angular momentum [17, 52, 58, 67].”
- Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications (2019, background): “Moreover, the extremely low-threshold for skyrmion excitation [1, 78, 107, 108] may promise the reduced power consumption of skyrmion synapse-based neuromorphic computing, which is highly desired for such device to be used for massive parallel computations.”