Richard SCHLITZ (Magnetism and Interface Physics, ETH Zürich, Switzerland)
Résumé : Magnons are quantized excitations of the magnetization texture in ordered magnets. As such they also allow to transport spin information. In this seminar, I will introduce a new paradigm in the field of magnonics, which is the study of electrically generated and detected magnon spin currents in heterostructures consisting of a magnetic insulator and a heavy metal. In such structures the spin transport via magnon diffusion can be inferred by static electrical transport measurements . Within this paradigm, a broad range of devices allowing spin information transport and logic operations—analogous to electronic devices—have already been implemented [2,3]. However, to realize the full potential of this branch of magnonics the lack of understanding of the involved magnon manifold as well as the absence of the magnon equivalent to an electric force are significant obstacles. I will first revisit the key features of non-local spin transport using heterostructures of yttrium iron garnet and platinum as a prototypical example system. I will introduce a recent collaborative effort to identify the exact nature of the magnons contributing to the nonlocal spin transport [4,5]. Finally, results on the controlled generation of magnon drift currents will be presented, where we revealed magnon drift currents that stem from the odd contribution of the interfacial Dzyaloshinskii-Moriya interaction to the magnon dispersion. We find good agreement between experiments and an extended spin transport theory which includes a finite drift velocity resulting from any inversion asymmetric interaction . This establishes that an effective magnon force can be implemented using the Dzyaloshinskii- Moriya interaction.
 Cornelissen et al., Nature Physics 11, 1022-1026 (2015).
 Ganzhorn et al., Applied Physics Letters 109, 022405 (2016).
 Wimmer et al., Physical Review Letters 123, 257201 (2019)
 Kohno et al., arXiv, 2210.08304 (2022).
 Kohno et al., arXiv, 2210.08283 (2022).
 Schlitz et al., Physical Review Letters 126, 257201 (2021)
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"Metallomesogens with complex architectures"