The Topological Hall Effect in CoGd Films Controlled by Hydrogen Migration under Gate Voltage

Abstract

AbstractThe topological Hall effect (THE) presents hump signals in the Hall resistance versus magnetic field hysteresis loop, showing promise for future spintronics due to its robust chiral magnetic textures. Here, it is shown that solid‐state protonic gating can control possible topological magnetic structures in CoGd thin films. Injecting H+ leads to sizable hump signals in the film. Magneto‐optical Kerr microscopy shows that induced hump signals in transporting measurements do not scale with magnetization, supporting topological magnetism. Successive hydrogen ion extraction completely erases the effect. Thus, topological magnetism manipulations are reversible, nonvolatile, and effective. Ab inito calculations and effective chiral spin models demonstrate that hydrogen injection remarkably enhances the Dzyaloshinskii–Moriya interaction over fourfold, stabilizing chiral structures contributing to the large THE. These findings reveal the vital role of hydrogen ions in topological magnetism and suggest that amorphous ferrimagnetic CoGd thin films are outstanding platforms for realizing controllable topological spintronics at room temperature.