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Nanoimaging of Ultrashort Magnon Emission by Ferromagnetic Grating Couplers at GHz Frequencies

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Baumgaertl Korbinian, Gräfe Joachim, Che Ping, Mucchietto Andrea, Förster Johannes, Träger Nick, Bechtel Michael, Weigand Markus, Schütz Gisela, Grundler Dirk,
Project Discovery and Nanoengineering of Novel Skyrmion-hosting Materials
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Original article (peer-reviewed)

Journal Nano Letters
Volume (Issue) 20(10)
Page(s) 7281 - 7286
Title of proceedings Nano Letters
DOI 10.1021/acs.nanolett.0c02645

Open Access

Type of Open Access Publisher (Gold Open Access)


On-chip signal processing at microwave frequencies is key for modern mobile communication. When one aims at small footprints, low power consumption, reprogrammable filters, and delay lines, magnons in low-damping ferrimagnets offer great promise. Ferromagnetic grating couplers have been reported to be specifically useful as microwave-to-magnon transducers. However, their interconversion efficiency is unknown and real-space measurements of the emitted magnon wavelengths have not yet been accomplished. Here, we image with subwavelength spatial resolution the magnon emission process into ferrimagnetic yttrium iron garnet (YIG) at frequencies up to 8 GHz. We evidence propagating magnons of a wavelength of 98.7 nm underneath the gratings, which enter the YIG without a phase jump. Counterintuitively, the magnons exhibit an even increased amplitude in YIG, which is unexpected and due to a further wavelength conversion process. Our results are of key importance for magnonic components, which efficiently control microwave signals on the nanoscale.