  Skyrmions and domain walls are typical spin textures of significant
technological relevance to magnetic memory and logic applications, where they
are used as carriers of information. The unique topology of skyrmions makes
them to display distinct dynamical properties compared to domain walls. Some
studies have demonstrated that the two topologically inequivalent magnetic
objects could be interconverted by cleverly designed geometric structures.
Here, we numerically address the skyrmion-domain wall collision in a magnetic
racetrack by introducing relative motion between the two objects based on a
specially designed junction. An electric current serves as the driving force
that moves a skyrmion toward a trapped domain-wall pair. We observe different
types of collision dynamics by changing the driving parameters. Most
importantly, the domain wall modulation of skyrmion transport is realized in
this system, allowing a set of domain wall-gated logical NOT, NAND, and NOR
gates to be constructed. By providing a promising logic architecture that is
fully compatible with racetrack memories, this work is expected to speed up the
development of skyrmion-based magnetic computation.
