Spin caloritronic nano-oscillator

TL;DR

This paper demonstrates that thermal gradients from ohmic heating can induce coherent magnetization oscillations and generate tunable microwave signals in YIG/Pt nanowires, advancing spin caloritronic device applications.

Contribution

It introduces a novel method of using heat-driven spin currents to excite magnetization auto-oscillations and produce microwave signals in nanoscale bilayer structures.

Findings

Thermal gradients can excite auto-oscillations of magnetization.

Ohmic heating injects pure spin current into YIG layer.

Generation of tunable microwave radiation from heat-driven dynamics.

Abstract

Energy loss due to ohmic heating is a major bottleneck limiting down-scaling and speed of nano-electronic devices, and harvesting ohmic heat for signal processing is a major challenge in modern electronics. Here we demonstrate that thermal gradients arising from ohmic heating can be utilized for excitation of coherent auto-oscillations of magnetization and for generation of tunable microwave signals. The heat-driven dynamics is observed in $\mathrm{Y_{3}Fe_{5}O_{12}/Pt}$ bilayer nanowires where ohmic heating of the Pt layer results in injection of pure spin current into the $\mathrm{Y_{3}Fe_{5}O_{12}}$ layer. This leads to excitation of auto-oscillations of the $\mathrm{Y_{3}Fe_{5}O_{12}}$ magnetization and generation of coherent microwave radiation. Our work paves the way towards spin caloritronic devices for microwave and magnonic applications.