Antiferromagnets with broken time-reversal symmetry (TRS) have launched a new direction in spintronics research, combining the advantageous dynamical properties of conventional antiferromagnets with the controllability typically associated with ferromagnets. However, antiferromagnetic domains are notoriously challenging to image in real space. X-ray magnetic circular dichroism (XMCD) offers a route to overcome this difficulty: XMCD contrast may be finite in TRS-breaking antiferromagnets with an appropriate magnetic space group. Here, we exploit this to image the cluster octupole domains in a focused ion beam-fabricated device of the noncollinear antiferromagnet ${\mathrm{Mn}}_3\mathrm{Sn}$. Using scanning transmission x-ray microscopy, we spatially resolve the weak preedge XMCD contrast (of 0.2%), achieving a contrast resolution better than 0.02%. We observe hysteretic switching of the ferroic cluster octupole order through both the XMCD contrast and the corresponding anomalous Hall effect within the same device. These results confirm the bulk nature of this contrast and establish XMCD-based microscopy as a powerful real-space imaging method for TRS-breaking antiferromagnets, including altermagnets, enabling future studies of their dynamics, switching, and symmetry-tunable phenomena.

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• Magnetic order
• Magnetism
• Focused ion beam
• X-ray imaging