  Recent research demonstrated the electrical switching of antiferromagnets via
intrinsic spin-orbit torque or the spin Hall effect of an adjacent heavy metal
layer. The electrical readout is typically realized by measuring the transverse
anisotropic magnetoresistance at planar cross- or star-shaped devices with four
or eight arms, respectively. Depending on the material, the current density
necessary to switch the magnetic state can be large, often close to the
destruction threshold of the device. We demonstrate that the resulting
electrical stress changes the film resistivity locally and thereby breaks the
fourfold rotational symmetry of the conductor. This symmetry breaking due to
film inhomogeneity produces signals, that resemble the anisotropic
magnetoresistance and is experimentally seen as a "saw-tooth"-shaped transverse
resistivity. This artifact can persist over many repeats of the switching
experiment and is not easily separable from the magnetic contribution. We
discuss the origin of the artifact, elucidate the role of the film
crystallinity, and propose approaches how to separate the resistive
contribution from the magnetic contribution.
