Figure 2: Spin configurations of a skyrmion, a meron and a DW pair.

(a–f) A skyrmion is created from a DW pair driven by spin transfer torque from the narrow part to the wide part of the nanowire. The spin direction is shown by yellow arrow. A yellow dot in the blue region shows that the spin is almost up, whereas a yellow dot in the red region shows that it is almost down. No dots are observed when the spin is almost perfectly up or down. The in-plane current density along −x direction is 1.8 μA nm⁻² in the wide part. (g–l) A meron is created when the in-plane current density along −x direction is 0.9 μA nm⁻² in the wide part.