Magnon-drag thermopile

M. V. COSTACHE; G. BRIDOUX; I. NEUMANN; S. O. VALENZUELA

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Conferencia; 19th International Conference on Magnetism; 2012

Thermoelectric effects in spintronics are gathering increasing attention as a means of controlling spininformation by using heat flow. Thermal magnons (spin-wave quanta) are expected to play a majorrole, however, the coupling between electrons and magnons in ferromagnetic metals remains poorlyunderstood. We demonstrate a conceptually new device that enables us to gather information on magnonelectronscattering and magnon-drag effects. The device resembles a thermopile formed by a largenumber of pairs of ferromagnetic wires placed between a hot and a cold source and connected thermallyin parallel and electrically in series. By controlling the relative orientation of the magnetization in pairsof wires, the magnon drag can be studied independently of the electron and phonon drag thermoelectriceffects. Measurements as a function of temperature reveal the effect on magnon drag following a variationof magnon and phonon populations. These results demonstrate the feasibility of directly convertingmagnon dynamics of nanomagnets into an electrical signal and could pave the way to novel thermoelectricdevices for energy harvesting.