Modulation of magnon spin transport in a magnetic gate transistor

We demonstrate a modulation of up to $18%$ in the magnon spin transport in a magnetic insulator $({\text{Y}}₃{\text{Fe}}₅{\text{O}}₁₂$, YIG) using a common ferromagnetic metal (permalloy, Py) as a magnetic control gate. A Py electrode, placed between two Pt injector and detector electrodes, acts as a magnetic gate in our prototypical magnon transistor device. By manipulating the magnetization direction of Py with respect to that of YIG, the transmission of magnons through the $\mathrm{Py}\ensuremath{\mid}\mathrm{YIG}$ interface can be controlled, resulting in a modulation of the nonequilibrium magnon density in the YIG channel between the Pt injector and detector electrodes. This study opens up the possibility of using the magnetic gating effect for magnon-based spin logic applications.