Complementary magnon transistors by comb-shaped gating currents

Complementary magnon transistors (CMTs) are desired to effectively regulate the transport of coherent spin waves. Here, using comb-shaped gating electrodes with a variable duty ratio (δ) and a gating current flowing through them, we were able to decrease or even increase the transmission of spin waves in a wide frequency range complimentarily. The reduction or amplification degree at opposite gating currents depends on δ. We further found that interference between spin waves transmitted through the gated and ungated regions was responsible for the gate tunability at low δ; at high δ, the inhomogeneous temperature and magnetic fields introduced by the gating currents can nontrivially deflect spin waves and leads to an opposite gate tunability. Realization of the CMT based on a dc gating current may pave the way toward coherent magnon devices and circuits, spin-wave processing, or lensing applications.