Berlin 2018 – scientific programme

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MA: Fachverband Magnetismus

MA 23: Non-ultrafast magnetization dynamics

MA 23.2: Talk

Wednesday, March 14, 2018, 09:45–10:00, H 0112

Local spin-wave dispersion and damping in thin yttrium iron garnet films — •Rouven Dreyer¹, Niklas Liebing¹, Eric R. J. Edwards^1,2, and Georg Woltersdorf¹ — ¹Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale), Germany — ²National Institute of Standards and Technology Boulder, CO, U.S.A.

By time-resolved magneto-optic imaging we investigate the spin-wave dispersion and spin-wave damping in yttrium iron garnet thin film samples with a thickness of 200 nm. Using the inhomogeneous magnetic field generated by a coplanar waveguide spin waves are excited at a fixed frequency while the wavelength is tuned by the external magnetic field. By imaging the excited spin waves with a scanning time-resolved MOKE setup and mapping their dispersion we identify a method to determine the damping of the homogeneous mode locally. Furthermore we find that in the vicinity of avoided crossings in the spin-wave dispersion the group velocity of excited spin waves is close to zero. Here we are able to extract the Gilbert damping parameter for localized spin waves. The obtained values are in good agreement with the results for the uniform mode. In comparison to inductive FMR measurements we find narrower linewidths for the uniform mode due to the local character of our measurements.