SPICE Workshop on Quantum Functionalities of Nanomagnets, June 17th - 19th 2025
Samuel Mañas-Valero
Spin-waves in magnetic films with micrometer-scale wavelengths at gigahertz frequencies, are promising for wave-based information devices with new functionalities. Realizing this promise requires accurate control of both the static magnetization and the spin-wave spectrum in microfabricated magnetic structures [1].
In this talk, I will introduce spin-wave sensing using spins in diamond. [2] In particular, we harness the magnetic anisotropy in a permalloy magnetic half-plane to control the magnetic texture and excite spin-waves with highly field-tunable wavelengths. Via diamond magnetometry [2], we image both the static magnetic field generated by the magnetic texture and the dynamic fields generated by the spin-waves near the film edge [fig. 1a-b]. This enables us to determine the magnetic anisotropy, the magnetization curling length, and to correlate these with the spatially varying spin-wavelengths. Rotating the magnetic bias field, we trigger the non-reciprocal nucleation of a domain wall that strongly modulates the spin-wave transport near the film edge.
Our results demonstrate how tuning the balance between the anisotropy and the magnetic bias field enables spin-wave control near magnetic edges, while highlighting the power of simultaneous static and dynamic imaging for studying the interplay between spin-waves and spin textures.
Figure 1. a) Overview of the NV magnetometry setup. A scanning tip with a single Nitrogen-Vacancy (NV) centre scans across a permalloy film, which is located next to a gold stripline. The inset shows the NV centre. b) 2D spatial map of spin-waves in the Damon-Eshbach configuration. The upper panel indicates the averaged contrast along the Y-axis.
SMV thanks the Kavli Institute of Nanoscience Delft via a Kavli Synergy Fellowship.
[2] F. Casola et al., Nat. Rev. Mater. 3 17088 (2018)