Spin caloritronic nano-oscillator

TLDR

Energy loss from ohmic heating limits the scaling and speed of nano‑electronic devices, and efficiently harvesting this heat for signal processing remains a major challenge. The study demonstrates that thermal gradients produced by ohmic heating can excite coherent auto‑oscillations of magnetization and generate tunable microwave signals. This effect is realized in Y₃Fe₅O₁₂/Pt bilayer nanowires, where ohmic heating of the Pt layer injects pure spin current into the Y₃Fe₅O₁₂ layer, driving the dynamics. The result is excitation of auto‑oscillations in the Y₃Fe₅O₁₂ magnetization and coherent microwave radiation, paving the way for spin caloritronic microwave and magnonic devices.

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.