  Charge ordered kagome lattices have been demonstrated to be intriguing
platforms for studying the intertwining of topology, correlation, and
magnetism. The recently discovered charge ordered kagome material ScV_6Sn_6
does not feature a magnetic groundstate or excitations, thus it is often
regarded as a conventional paramagnet. Here, using advanced muon-spin rotation
spectroscopy, we uncover an unexpected hidden magnetism of the charge order. We
observe a striking enhancement of the internal field width sensed by the muon
ensemble, which takes place within the charge ordered state. More remarkably,
the muon spin relaxation rate below the charge ordering temperature is
substantially enhanced by applying an external magnetic field. Taken together
with the hidden magnetism found in AV_3Sb_5 (A = K, Rb, Cs) and FeGe kagome
systems, our results suggest ubiqitous time-reversal symmetry-breaking in
charge ordered kagome lattices.
