  Antiferromagnets have a number of favourable properties as active elements in
spintronic devices, including ultra-fast dynamics, zero stray fields and
insensitivity to external magnetic fields . Tetragonal CuMnAs is a testbed
system in which the antiferromagnetic order parameter can be switched
reversibly at ambient conditions using electrical currents . In previous
experiments, orthogonal in-plane current pulses were used to induce 90 degree
rotations of antiferromagnetic domains and demonstrate the operation of
all-electrical memory bits in a multi-terminal geometry . Here, we demonstrate
that antiferromagnetic domain walls can be manipulated to realize stable and
reproducible domain changes using only two electrical contacts. This is
achieved by using the polarity of the current to switch the sign of the
current-induced effective field acting on the antiferromagnetic sublattices.
The resulting reversible domain and domain wall reconfigurations are imaged
using x-ray magnetic linear dichroism microscopy, and can also be detected
electrically. The switching by domain wall motion can occur at much lower
current densities than those needed for coherent domain switching.
