Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Caloric effects in ferromagnetic materials
MA 35.5: Vortrag
Mittwoch, 3. April 2019, 16:00–16:15, H52
Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films — •Timo B. Noack1, Halyna Yu. Musiienko-Shmarova1, Thomas Langner1, Frank Heussner1, Viktor Lauer1, Björn Heinz1, Dmytro A. Bozhko1, Vitaliy I. Vasyuchka1, Anna Pomyalov2, Victor L’vov2, Burkard Hillebrands1, and Alexander A. Serga1 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, Kaiserslautern, Germany — 2Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
We study the transient behavior of the spin current generated by the Longitudinal Spin Seebeck Effect (LSSE) in a set of platinum-coated Yttrium Iron Garnet (YIG) films of different thicknesses. The LSSE is induced by means of pulsed microwave heating of the Pt layer and the spin currents are measured electrically using the inverse spin Hall effect. We demonstrate that the time evolution of the LSSE is determined by the evolution of the thermal gradient triggering the flux of thermal magnons in the vicinity of the YIG/Pt interface. These magnons move ballistically within the YIG film with constant group velocity. The ballistic flight of the magnons with energies above 20 K is a result of their almost linear dispersion law, similar to that of acoustic phonons. By fitting the time-dependent LSSE signal for different film thicknesses varying by almost an order of magnitude, we found that the effective propagation length is practically independent of the YIG film thickness.