Defect-engineered chiral bubble domains and topological Hall effect in the Kagome ferromagnet Co3+xSn2-xS2

Chiral spin textures such as skyrmions and bubble domains are typically stabilized by intrinsic Dzyaloshinskii–Moriya interaction (DMI) in non-centrosymmetric magnets, making their realization in centrosymmetric crystals a longstanding challenge. Here, we show that controlled non-stoichiometry in the Kagome ferromagnet Co _3 + x ​Sn _2 − x S ₂ ​ ​ provides a defect-based route to DMI and topological spin textures. Density-functional-theory calculations reveal that out-of-plane Co/Sn anti-site defects locally break inversion and mirror symmetries, generating a sizable DMI (~ 0.38 meV), whereas pristine and in-plane anti-site configurations yield negligible DMI. Magnetization measurements on non-stoichiometric single crystals show bow-tie-shaped hysteresis and metamagnetic-like transitions, signaling intermediate non-collinear states. Magnetic-force microscopy (MFM) on x  = 0.075 directly visualizes bubble-like domains with micrometer-scale chiral domain walls, appearing only within a narrow magnetic-field window. In the same field range, Hall measurements uncover a pronounced topological Hall contribution whose magnitude and width are strongly sensitive to the magnetic-field sweep rate, demonstrating their dynamic, non-equilibrium nature. Our results establish a direct microscopic link between anti-site–induced local symmetry breaking, DMI, and emergent topological Hall transport in a centrosymmetric Kagome metal, identifying defect engineering as a powerful strategy to create and tune chiral spin textures for field- and history-controllable spintronic functionalities.