Figure 2. Velocity-current curves for the skyrmion motions.

(a), A comparison among the skyrmion velocities obtained for each scenario (A, B, C, and D). The current j_FE is related to the scenarios A and C while j_HM to the scenarios B and D. (b), Sketch of the motion mechanism of the Néel skyrmion driven by the SHE along the y-direction. (c), Sketch of the motion mechanism of the Bloch skyrmion driven by the SHE along the x-direction. (d), Skyrmion velocities as a function of j_HM obtained for the scenario B: (i) thermal fluctuations (T = 350 K) and perfect strip (red curve) and (ii) thermal fluctuations (T = 350 K) and rough strip (blue curve). The arrows for (b) and (c) refer to the in-plane components of the magnetization, the spin-polarization of j_HM is also displayed.