Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 67: Poster 4

MA 67.1: Poster

Friday, March 24, 2017, 09:30–13:00, P2-OG3

Microwave excitation and optical detection of spin wave beams in NiFe films — •Helmut Körner, Johannes Stigloher, and Christian Back — Institut für Experimentelle und Angewandte Physik, Uni Regensburg, Germany

Only recently, Gruszecki et al. [1] presented an approach enabling the generation of narrow spin wave (SW) beams in thin homogenous nanosized ferromagnetic films by microwave current. Using micromagnetic simulations they showed that the desired beam-type behaviour can be achieved with the aid of a properly designed coplanar waveguide transducer generating a non-uniform microwave magnetic field. The resulting SW beams propagate over distances of several micrometers. Moreover, they state that their approach can be generalized to different magnetization configurations, e.g. forward-volume or Damon-Eshbach (DE) geometry, respectively, and yield multiple SW beams of different width at the same frequency.

Here, we present the results of an experimental study on SW beams propagating in the DE geometry in a 50 nm thick NiFe film by imaging these beams using time-resolved scanning Kerr microscopy (TR-MOKE). We show that it is possible to excite and image (multiple) SWs beams of varying width at the same frequency by carefully tuning the amplitude of the externally applied magnetic field. The shape of the SW beams is inherently determined by the anisotropic nature of the DE SW dispersion for small wave numbers and is also affected by the shape of the coplanar waveguide.

[1] P. Gruszecki et. al., Sci. Rep. 6, 22367 (2016)