Reversible manipulation of the topological Hall effect by hydrogen

We demonstrate that the topological Hall effect (THE) in a $\mathrm{Pd}/{\mathrm{Tm}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ (TmIG) bilayer can be delicately manipulated by ${\mathrm{H}}_{2}$ with a maximum $100%$ tunability in the reversible manner. This phenomenon originates from the variation of the Dzyaloshinskii-Moriya interaction (DMI) at the Pd/TmIG interface, which can be effectively tuned by the absorption/desorption of ${\mathrm{H}}_{2}$ in Pd. Furthermore, we show that the THE in a Pd/W/TmIG trilayer barely changes by applying ${\mathrm{H}}_{2}$ even the W layer is only 1-nm-thick, which indicates that the DMI generated by the W/TmIG interface is responsible for the THE, and the change in the net spin accumulation at the W/TmIG interface has no effect on the THE. Finally, we show that the Cu/TmIG interface can generate sufficient interfacial DMI to induce THE, even Cu is a light metal with weak spin-orbit coupling. Our study provides a simple approach to delicately manipulate the THE in spintronic devices and paves a practical way for developing more sensitive hydrogen sensors based on the spintronic technology.