Dresden 2020 – scientific programme

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MA: Fachverband Magnetismus

MA 42: Posters Magnetism I

MA 42.14: Poster

Wednesday, March 18, 2020, 15:00–18:00, P3

Non-linear spin-wave generation at low magnetic bias fields — •Rouven Dreyer, Chris Körner, Niklas Liebing, and Georg Woltersdorf — Martin Luther University Halle-Wittenberg, Institute of Physics, Von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany

For small magnetic stiffnesses the non-linear spin-wave excitations are not adequately described by Suhl instability processes [1]. It was shown that in this regime spin waves at fractional multiples of the pump frequency (such as 3/2 ω) are excited [1]. Here we demonstrate the 3/2 ω non-linear spin-wave (NLSW) generation in Ni₈₀Fe₂₀ microstructures using different scanning magneto-optical microscopy approaches. A special version time-resolved Kerr microscopy [2] allows for phase-resolved imaging and provides access to the wave vectors of parametrically excited NLSW at 3/2 ω above the threshold rf-field. The threshold behavior of this type of non-linearities is compared with results from a NV-center photoluminescence microscope using the same sample. Since the NV-center is very small signal averaging in the area of the laser spot is avoided, therefore a lack of phase stability in space and time does not reduce the signal and the NV-centers can be utilized to investigate the NLSW excitation for large wave vectors close to the threshold condition. Our results are further supported by micro-focussed Brillouin light scattering (µ-BLS) experiments performed on the same samples. [1] H. G. Bauer et al., Nat. Commun. 6:8274 (2015) [2] R. Dreyer et al., arXiv:1803.04943 (2018)