Ultrafast time-resolved observation of non-thermal current-induced switching in an antiferromagnetic Weyl semimetal

Antiferromagnets have gained a growing interest for next-generation spintronic applications. Among them, the antiferromagnetic Weyl semimetal Mn₃Sn stands out because of its electrical and magnetic properties driven by its non-collinear spin structure at room temperature. Despite research progress on the current-induced switching of the magnetic octupole in Mn₃Sn, the ultrafast switching inherent to the antiferromagnet remains to be resolved, and the underlying mechanism is yet elusive. Here we measure the spatiotemporally resolved current-induced switching dynamics in polycrystalline Mn₃Sn films using ultrafast magneto-optical Kerr effect imaging, with current pulses as short as 140 ps. Our results directly reveal two distinct switching regimes depending on the intensity and duration of the current pulse: a non-thermal process that does not require the transient melting of antiferromagnetic order, and a temperature-assisted process that relies on heating above the magnetic ordering temperature. Our work highlights the potential of Mn₃Sn towards ultrafast magnetic recording devices.