Control of non-local magnon spin transport via magnon drift currents*

A key research focus in the field of magnonics are electrically generated and detected magnon spin currents in heterostructures consisting of a magnetic insulator and a heavy metal. Careful device design enables the investigation of spin transport via magnon diffusion [1]. However, the absence of the magnon equivalent of an electric force is an obstacle for realizing the full potential of pure spin currents. In this work, we report the controlled generation of magnon drift currents in heterostructures of yttrium iron garnet and platinum. Relying on the electrical injection and detection of incoherent magnons, we find magnon drift currents that stem from the odd contribution of the interfacial Dzyaloshinskii-Moriya interaction to the magnon dispersion. By changing the orientation of the magnetic field, we can control the magnon drift, where a maximum change of the magnon propagation length by up to ±6% relative to diffusion can be achieved. We find good agreement between experiments and an extended spin transport theory which includes a finite drift velocity resulting from any inversion asymmetric interaction [2].

[1] Cornelissen et al., Nature Physics 11, 1022-1026 (2015).

[2] Schlitz et al., Physical Review Letters 126, 257201 (2021).