  Magnetism in two-dimensional materials reveals phenomena distinct from bulk
magnetic crystals, with sensitivity to charge doping and electric fields in
monolayer and bilayer van der Waals magnet CrI3. Within the class of layered
magnets, semiconducting CrSBr stands out by featuring stability under ambient
conditions, correlating excitons with magnetic order and thus providing strong
magnon-exciton coupling, and exhibiting peculiar magneto-optics of
exciton-polaritons. Here, we demonstrate that both exciton and magnetic
transitions in bilayer and trilayer CrSBr are sensitive to voltage-controlled
field-effect charging, exhibiting bound exciton-charge complexes and
doping-induced metamagnetic transitions. Moreover, we demonstrate how these
unique properties enable optical probes of local magnetic order, visualizing
magnetic domains of competing phases across metamagnetic transitions induced by
magnetic field or electrostatic doping. Our work identifies few-layer CrSBr as
a rich platform for exploring collaborative effects of charge, optical
excitations, and magnetism.
