Electrical Manipulation of Magnon Diffusion Length in Pt/YIG Three-Terminal Devices

Magnons transport spin angular momentum without involving charge current, offering the potential for energy-efficient spintronic devices. While the generation, manipulation, and detection of magnons, key elements for magnonic devices, have been demonstrated in various systems, electrical control of the magnon diffusion length (λ_m) has not been reported. In this work, we demonstrate electrical control of λ_m in three-terminal Pt/YIG devices, where injector-to-detector distance and modulator widths are systematically varied. We observe that λ_m can be effectively tuned by the modulation current, with strong dependence on the injection current (<i>I</i>_inj). At low <i>I</i>_inj, λ_m increases from 0.84 to 1.8 μm under a modulation current density of 5.5 × 10⁷ A/cm². Remarkably, the modulation efficiency improves at higher <i>I</i>_inj, attributed to the overpopulation of subthermal magnons and their increased sensitivity to current-induced spin-orbit torque. Our findings highlight the potential of the electrical manipulation of λ_m, paving the way for the development of practical magnonic devices.