Exchange magnon induced resistance asymmetry in permalloy spin-Hall oscillators

TL;DR

This paper studies how exchange magnons affect resistance asymmetry in permalloy spin-Hall oscillators, revealing their significant role in device operation through experimental and theoretical analysis.

Contribution

It introduces a model linking exchange magnons to resistance changes, advancing understanding of spin-Hall oscillator dynamics.

Findings

Resistance asymmetry linked to exchange magnons

Model accurately explains resistance reduction

Exchange magnons significantly impact oscillator performance

Abstract

We investigate magnetization dynamics in a spin-Hall oscillator using a direct current measurement as well as conventional microwave spectrum analysis. When the current applies an anti-damping spin-transfer torque, we observe a change in resistance which we ascribe to the excitation of incoherent exchange magnons. A simple model is developed based on the reduction of the effective saturation magnetization, quantitatively explaining the data. The observed phenomena highlight the importance of exchange magnons on the operation of spin-Hall oscillators.