Reversible Control of Ferrimagnetic Skyrmion Generation and Motion via Hydrogen Migration Under Electric Field.

Abstract

Skyrmions, chiral magnetic textures distinguished by their small dimensions and structural stability, are promising information carriers for advanced spintronic devices. Among various skyrmions, ferrimagnetic skyrmions exhibit a reduced skyrmion Hall angle, which makes them particularly suitable for practical applications. In this study, we demonstrate that ionic liquid gating can effectively tune the density, diameter, and magnetic field range of the skyrmion stability in ferrimagnetic Gd/Co-based heterostructures by more than one order of magnitude at room temperature. Such significant changes are related to the electric-field driven hydrogen ions migration: a positive gate voltage (V_G) drives H⁺ migration into Pt and Gd layers, reducing the perpendicular magnetic anisotropy and resultant skyrmion equilibrium and nucleation energy, whereas a negative V_G produces the opposite effect. Furthermore, the H⁺ accumulation at positive V_G suppresses the current-driven skyrmion motion owing to the decrease in the Dzyaloshinskii-Moriya interaction constant. The obtained results reveal that the electric-field driven ion migration is a powerful tool for manipulating both the static and dynamic performance characteristics of ferrimagnetic skyrmions, which can advance the development of high-efficiency skyrmion-based spintronic devices with logic operations and neuromorphic computing functionalities.