Figure 4: Skyrmion racetrack.
From: A reversible conversion between a skyrmion and a domain-wall pair in a junction geometry
(a) Top-view of the spin structure at five different times of the simulation, corresponding to the five vertical lines in b. (b) Time-evolution of the topological number Q. (c) Skyrmion array generations. Q increases by one unit as one skyrmion is created. The purple arrow represents the position where an external radio-frequency magnetic field is applied to generate DW pairs at a constant time interval.
