Magnon-drag thermopile

TL;DR

This paper introduces a novel device that enables detailed study of magnon-electron interactions and magnon-drag effects in thermoelectric spintronics, providing insights into heat and spin transport at the nanoscale.

Contribution

A new thermopile-based device is demonstrated to independently analyze magnon-drag effects, advancing understanding of electron-magnon interactions in thermoelectric spintronics.

Findings

Magnon-drag effects vary with temperature, reflecting changes in magnon and phonon populations.

The device can isolate magnon-drag from electron and phonon-drag effects.

Results improve understanding of thermal spin transport mechanisms.

Abstract

Thermoelectric effects in spintronics are gathering increasing attention as a means of managing heat in nanoscale structures and of controlling spin information by using heat flow. Thermal magnons (spin-wave quanta) are expected to play a major role, however, little is known about the underlying physical mechanisms involved. The reason is the lack of information about magnon interactions and of reliable methods to obtain it, in particular for electrical conductors because of the intricate influence of electrons. Here, we demonstrate a conceptually new device that allows us to gather information on magnon-electron scattering and magnon-drag effects. The device resembles a thermopile formed by a large number of pairs of ferromagnetic wires placed between a hot and a cold source and connected thermally in parallel and electrically in series. By controlling the relative orientation of the magnetization in pairs of wires, the magnon-drag can be studied independently of the electron and phonon-drag thermoelectric effects. Measurements as a function of temperature reveal the effect on magnon drag following a variation of magnon and phonon populations. This information is crucial to understand the physics of electron-magnon interactions, magnon dynamics and thermal spin transport.