  Searching for new methods controlling antiferromagnetic (AFM) domain wall is
one of the most important issues for AFM spintronic device operation. In this
work, we study theoretically the domain wall motion of an AFM nanowire, driven
by the axial anisotropy gradient generated by external electric field, allowing
the electro control of AFM domain wall motion in the merit of ultra-low energy
loss. The domain wall velocity depending on the anisotropy gradient magnitude
and intrinsic material properties is simulated based on the
Landau-Lifshitz-Gilbert equation and also deduced using the energy dissipation
theorem. It is found that the domain wall moves at a nearly constant velocity
for small gradient, and accelerates for large gradient due to the enlarged
domain wall width. The domain wall mobility is independent of lattice dimension
and types of domain wall, while it is enhanced by the Dzyaloshinskii-Moriya
interaction. In addition, the physical mechanism for much faster AFM wall
dynamics than ferromagnetic wall dynamics is qualitatively explained. This work
unveils a promising strategy for controlling the AFM domain walls, benefiting
to future AFM spintronic applications.
