Electrically induced strong modulation of magnons transport in ultrathin magnetic insulator films

Magnon transport through a magnetic insulator can be controlled by current-biased heavy-metal gates that modulate the magnon conductivity via the magnon density. Here, we report nonlinear modulation effects in 10$,$nm thick yttrium iron garnet (YIG) films. The modulation efficiency is larger than 40%/mA. The spin transport signal at high DC current density (2.2$times 10^{11},$A/m$^{2}$) saturates for a 400$,$nm wide Pt gate, which indicates that even at high current levels a magnetic instability cannot be reached in spite of the high magnetic quality of the films.