[en] We report that the ferromagnetic resonance (FMR) response of the CoFeB/HfO₂ heterostructures is stabilized and reversibly manipulated by ionic gel. Ionic gel with excellent flexibility is used as a medium to form an electric field. When a 4 V gate voltage is applied, the resonance field H _r and peak-to-peak linewidth ΔH _pp at different angles are regulated. When θ = 20°, the H _r is regulated up to 82 Oe. When θ = 70°, ΔH _pp is tuned up to 75 Oe. When the gate voltage is repeatedly applied, the FMR spectra can be freely switched between the initial state and the gated state. Our study provides an effective method to manipulate the damping of the magnetic film stably and reversibly. (paper)