Manipulating carrier density through gate effects, both in electrostatic charge storage and electrochemical intercalation mode, offers powerful control over material properties, although commonly restricted to ultrathin films or van der Waals materials. Here we demonstrate the application of gate-driven carrier modulation in the microdevice of magnetic Weyl semimetal ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$, fabricated from a bulk single crystal via focused ion beam (FIB). We discover a gated phase of ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ featuring electron doping exceeding $5\times {10}^{21}\mathrm{c}{\mathrm{m}}^{-3}$, resulting in the Fermi energy shift of 200 meV. The carrier density dependent anomalous Hall conductivity shows fair agreement with density functional theory (DFT) calculation, which also predicts intercalated ${\mathrm{Li}}^{+}$ ion stabilization within the anion layer while maintaining the kagome-lattice intact. This likely explains the observed rigid band behavior and constant Curie temperature, contrasting with magnetic site substitution experiments. Our findings suggest ionic gating on FIB devices broadens the scope of gate tuning in quantum materials.

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• Doping effects
• Electrochemistry
• Magnetotransport
• Devices
• Weyl semimetal
• Focused ion beam