Skyrmion Motion in Channels with Engineered Dzyaloshinskii-Moriya Interactions

Fast and efficient current-driven manipulation of skyrmions is vital for future design of skyrmion-based memory devices. Given this, it is important to find ways to increase the velocity that skyrmions can move when driven by current. We consider both spin transfer torque and spin orbit torque drives. We report on a proposed device geometry that makes use of spatial variation of the strength of the Dzyaloshinskii-Moriya interaction to greatly increase the maximum velocity that the skyrmion can achieve in the channel. We also investigate the relationship between skyrmion size and velocity when driven by current. Using a combination of simulations and analytical formulas, we show that the skyrmion motion in our proposed geometry can lead to a several times increase in the maximum achievable skyrmion velocity as compared to a physical narrow channel device.