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MA: Fachverband Magnetismus
MA 48: Magnetization / Demagnetization Dynamics IV
MA 48.9: Vortrag
Donnerstag, 19. März 2015, 17:00–17:15, EB 301
A scenario for dynamic magnonic spin-wave traps — Frederik Busse1, •Maria Mansurova1, Benjamin Lenk1, Marvin von der Ehe2, and Markus Münzenberg2 — 1I. Physikalisches Institut, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Institut für Physik, Greifswald University, Felix-Hausdorff-Straße 6, 17489 Greifswald, Germany
This work contributes to the understanding of spin waves behavior in periodically structured magnetic materials [1,2] subject to a heat gradient. We use an all-optical approach to both excite and detect spin waves using short (femtosecond) pulses. The femosecond laser pulse is used twofold: It allows generating spin-waves locally, and as we demonstrate in this work, the same pulse can be used to create defined thermal gradient in a periodic array of antidots. The saturation magnetization varies as a function of temperature due to the spatial thermal profile induced by the femtosecond pump pulse that persists for up to one nanosecond. We consistently observe a shift of 0.5 GHz of the excited spin waves towards higher frequencies as we perform spatially-resolved measurements. Moreover, no spin waves are detected outside the excitation spot. This is explained by considering that a temperature gradient imposes additional scattering as spin waves are continuously reflected when entering a colder region with higher saturation magnetization and can be used as a dynamic trap for the femtosecond laser driven spin-wave excitations.
[1] H. Ulrichs, et al. Applied Physics Letters 97, 092506 (2010)
[2] B. Lenk, et al. Physics Reports 507, 107 (2011)