Quantum Sensing of Nanoscale Magnetic Domains and Spin dynamics in Noncollinear Antiferromagnet Mn₃Sn

Noncollinear antiferromagnets with novel magnetic order, vanishingly small net magnetization, and exotic spin properties hold enormous promise for developing next-generation, spintronic technologies. A major ongoing research focus of this community is to explore, control, and harness unconventional magnetic phases of this emergent material system in order to deliver state-of-the-art functionalities for modern microelectronic applications. Here we report direct imaging of magnetic domains of polycrystalline Mn₃Sn films, a prototypical noncollinear chiral antiferromagnet, using nitrogen-vacancy-based single-spin scanning microscopy. Nanoscale evolution of local stray field patterns of Mn₃Sn samples are systematically investigated in response to external driving forces, revealing the characteristic “heterogeneous” magnetic switching behaviors in polycrystalline textured Mn₃Sn films. Our results contribute to a comprehensive understanding of inhomogeneous magnetic orders of noncollinear antiferromagnets, highlighting the potential of nitrogen-vacancy centers to investigate microscopic spin behaviors in a broad range of emergent condensed matter systems.