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arXiv · 2207.02798

Filtering and imaging of frequency-degenerate spin waves using nanopositioning of a single-spin sensor

Brecht G. Simon·Samer Kurdi·Joris J. Carmiggelt·Michael Borst·Allard Katan·Toeno van der Sar
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Abstract

Nitrogen-vacancy (NV) magnetometry is a new technique for imaging spin waves in magnetic materials. It detects spin waves by their microwave magnetic stray fields, which decay evanescently on the scale of the spin-wavelength. Here, we use nanoscale control of a single-NV sensor as a wavelength filter to characterize frequency-degenerate spin waves excited by a microstrip in a thin-film magnetic insulator. With the NV-probe in contact with the magnet, we observe an incoherent mixture of thermal and microwave-driven spin waves. By retracting the tip, we progressively suppress the small-wavelength modes until a single coherent mode emerges from the mixture. In-contact scans at low drive power surprisingly show occupation of the entire iso-frequency contour of the two-dimensional spin-wave dispersion despite our one-dimensional microstrip geometry. Our distance-tunable filter sheds light on the spin-wave band occupation under microwave excitation and opens opportunities for imaging magnon condensates and other coherent spin-wave modes.

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Brecht G. Simon, Samer Kurdi, Joris J. Carmiggelt, Michael Borst, Allard Katan, Toeno van der Sar. 2022-07-06. Filtering and imaging of frequency-degenerate spin waves using nanopositioning of a single-spin sensor. https://doi.org/10.1021/acs.nanolett.2c02791

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