  Magnetic racetrack memory (RTM) uses a series of either domains or skyrmions
as data bits along nanowires. However, it lacks reading error detection
capability in nanowires, which requires high electric current density for the
deterministic motion of domain walls (DWs) or skyrmions. Here, we propose a
method of a reading error-detectable RTM and explore domain-stored skyrmion
structures for this RTM. This method uses domains as memory cells and assigns
the presence and absence of a skyrmion in a domain to different bits, enabling
the electrical signal of any memory cells to output the opposite sign to that
of the adjacent memory cells. Using simulations and Lorentz microscopy, we
demonstrate that perpendicularly magnetized nanowires with relatively large
Dzyaloshinskii-Moriya interaction can achieve domain-stored skyrmion
structures. Additionally, our simulations show that when DWs approach to
skyrmions during spin-orbit torque-induced motion, angular momentum transfers
from DWs to skyrmions, resulting in fast motion of skyrmions.
