Skin-effect-mediated magnetoionic control of charge transport in thick layers

In the rapidly developing area of magnetoionics (MI), which combines electrochemistry and magnetism, changes in the surface chemistry of magnetic materials in response to gate voltages cause dramatic modifications in the magnetic characteristics, resulting in low power-consuming charge transport tuning. Due to the surficial character, only magnetic thin films have been addressed for the MI effect’s role in controlling charge transfer. Here, we show how it can be used to regulate the transit of charges in bulk magnetic materials. This is accomplished by combining high-permeability magnetic materials with a high-frequency passing current, allowing the skin effect and the MI effect to control the magnetic materials’ impedance due to the impedance’s high sensitivity to magnetic permeability. Our in-situ impedance measurement and magneto-optical characterization show the role of redox reactions at the surface in controlling impedance in magnetic materials. This research paves the way for using the MI effect in high-permeability bulk magnetic materials.