Effect of external field on current-induced skyrmion dynamics in a nanowire

We investigate the effect of external field on current-induced skyrmion dynamics in bilayer structures with interfacial Dzyaloshinskii-Moriya interaction. We find that the skyrmion velocity can be changed depending on the direction and magnitude of external magnetic field. Perpendicular magnetic field changes the velocity through the change in the skyrmion size. On the other hand, in-plane magnetic fields distort the magnetic skyrmion, which in turn affects the maximum skyrmion velocity obtained just before the annihilation of skyrmion at nanowire edges. Our results show that skyrmion velocity can be increased by applying magnetic fields along a proper direction.