Inertia, diffusion and dynamics of a driven skyrmion

Abstract

Skyrmions recently discovered in chiral magnets are a promising candidate for magnetic storage devices because of their topological stability, small size ($\sim 3-100$nm), and ultra-low threshold current density ($\sim 10^6$A/m${}^2$) to drive their motion. However, the time-dependent dynamics has hitherto been largely unexplored. Here we show, by combining the numerical solution of the Landau-Lifshitz-Gilbert equation and the analysis of a generalized Thiele's equation, that inertial effects are almost completely absent in skyrmion dynamics driven by a time-dependent current. In contrast, the response to time-dependent magnetic forces and thermal fluctuations depends strongly on frequency and is described by a large effective mass and a (anti-) damping depending on the acceleration of the skyrmion. Thermal diffusion is strongly suppressed by the cyclotron motion and is proportional to the Gilbert damping coefficient $\alpha$. This indicates that the skyrmion position is stable, and its motion responds to the time-dependent current without delay or retardation even if it is fast. These findings demonstrate the advantages of skyrmions as information carriers.

9 pages, 10 figures

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Cited by in corpus (6)

• Advances in the Physics of Magnetic Skyrmions and Perspective for Technology
• Memory functions of magnetic skyrmions
• Nano-to-micro spatiotemporal imaging of magnetic skyrmion's life cycle
• Configurational entropy of magnetic skyrmions as an ideal gas
• How a skyrmion can appear both massive and massless
• Supercurrent-induced Skyrmion dynamics and Tunable Weyl points in Chiral Magnet with Superconductivity