  Antiferromagnets offer spintronic device characteristics unparalleled in
ferromagnets owing to their lack of stray fields, THz spin dynamics, and rich
materials landscape. Microscopic imaging of aniferromagnetic domains is one of
the key prerequisites for understading physical principles of the device
operation. However, adapting common magnetometry techniques to the
dipolar-field-free antiferromagnets has been a major challenge. Here we
demonstrate in a collinear antiferromagnet a thermoelectric detection method by
combining the magneto-Seebeck effect with local heat gradients generated by
scanning far-field or near-field techniques. In a 20 nm epilayer of uniaxial
CuMnAs we observe reversible 180 deg switching of the N\'eel vector via domain
wall displacement, controlled by the polarity of the current pulses. We also
image polarity-dependent 90 deg switching of the N\'eel vector in a thicker
biaxial film, and domain shattering induced at higher pulse amplitudes. The
antiferromagnetic domain maps obtained by our laboratory technique are compared
to measurements by the established synchrotron microscopy using X-ray magnetic
linear dichroism.
