Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena
MA 48.3: Vortrag
Donnerstag, 23. März 2017, 10:00–10:15, HSZ 101
Parametric excitation of magnons in YIG films from cryogenic to above room temperatures — •Laura Mihalceanu1, Vitaliy I. Vasyuchka1, Dmytro A. Bozhko1,2, Thomas Langner1, Burkard Hillebrands1, and Alexander A. Serga1 — 1Fachbereich Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, Germany — 2Graduate School Materials Science in Mainz, Germany
Parameric pumping is a powerful tool to study fundamental properties of magnetization dynamics since it allows for the efficient excitation of magnons in a wide range of wavenumbers. By this, the efficient magnon injection into the spin system of yttrium iron garnet (YIG) films enabled the observation of such prominent phenomena as magnon Bose-Einstein condensates (BECs) and magnon supercurrents. Since until now all related experiments have been performed under normal ambient conditions, moving to cryogenic temperatures is of high interest, as a temperature decrease is expected to increase both the density and the lifetime of a magnon BEC significantly. The elongated BEC lifetime will allow to investigate the BEC’s dynamics at long time scales and will help to reveal, e.g., such relatively slow effects as Josephson oscillations. As a first step toward low-temperature magnon BECs, we study the parametric excitation of dipolar and exchange magnons in the temperature range from 40 K to 340 K. We address the impact of temperature on the saturation magnetization and reveal the behavior of the magnon relaxation parameter on the wide temperature scale. =-1
The work is supported by the DFG within the SFB/TR 49.