Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Magnetism Poster A

MA 15.41: Poster

Dienstag, 2. April 2019, 10:00–13:00, Poster E

Investigation of non-linear spin-wave excitation at low magnetic bias field — •Lea Apel, Rouven Dreyer, and Georg Woltersdorf — Institutte of Physics, Martin-Luther-Universität Halle-Wittenberg

Recently, it was demonstrated that the Suhl instability processes describing parametric spin wave excitations are not an adequate model at low magnetic bias fields [1]. In the low field regime a novel instability process dominates the response at high excitation amplitudes. This process leads to critical spin-wave modes which can be parametrically driven at half integer multiplies of excitation frequency.

Here we use micro-focus Brillouin light scattering (μBLS) to study the formation of 3/2 ω and 5/2 ω non-linear spin-wave excitations and the corresponding threshold rf-amplitudes for this parametric process in Permalloy microstructures. Simultaneously we detect the spatial dependence of the uniform mode as well as the parametrically excited spin waves. Overall we find agreement with the critical behavior prediction in [1] at small magnetic bias fields. Our results are supported by magneto-optical microscopy expriments which map the spin waves in a phase resolved fashion.

[1]H.G. Bauer et al., Nat. Commun. 6, 8274(2015)