Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 5: Spincaloric Transport

MA 5.7: Vortrag

Montag, 14. März 2011, 12:30–12:45, HSZ 04

Magnon mediated heat transport — •Vitaliy I. Vasyuchka, Alexander A. Serga, Andrii V. Chumak, and Burkard Hillebrands — FB Physik and Landesforschungszentrum OPTIMAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany

We report on measurements of heat transport mediated by a coherent magnon current in a magnetic medium. We used long-wavelength dipolar-dominated spin waves propagating along the magnetization direction in a tangentially magnetized yttrium iron garnet film. The temperature distribution in the film was visualized by means of an infrared thermography technique with a thermal sensitivity of 0.1 ^∘C and a spatial resolution of 200 µm. A bias magnetic field of 1780 Oe was chosen to allow the effective excitation and propagation of magnons with wavevectors of the order of 100 rad/cm at 7 GHz frequency. In the presence of travelling magnons excited by applying a continuous microwave signal power of 100 mW, a strong heating of the sample (up to 23 ^∘C) was observed around the input antenna. This heat is caused by the transfer of energy from the magnon system into the phonons. Detuning of the bias field to 1700 Oe when no magnons could be excited at the given frequency resulted in the disappearance of the observed heating effect. Comparing the obtained temperature distribution along the film with the heat profile created by a DC current in the antenna the efficiency of the travelling magnons in the process of heat transport was estimated.