The Discrete Noise of Magnons

TL;DR

This paper investigates the fundamental noise characteristics of magnonic devices, revealing that their low-frequency noise is dominated by random telegraph signals rather than 1/f noise, with noise levels increasing at nonlinear dissipation thresholds.

Contribution

It provides the first detailed analysis of low-frequency noise in magnonic devices, highlighting the dominance of telegraph signal noise and its dependence on power levels, contrasting with electronic device noise.

Findings

Low-frequency noise in magnonic devices is dominated by telegraph signals.

Noise level increases sharply at the onset of nonlinear dissipation.

Magnonic noise characteristics differ fundamentally from electronic counterparts.

Abstract

Magnonics is a rapidly developing subfield of spintronics, which deals with devices and circuits that utilize spin currents carried by magnons - quanta of spin waves. Magnon current, i.e. spin waves, can be used for information processing, sensing, and other applications. A possibility of using the amplitude and phase of magnons for sending signals via electrical insulators creates conditions for avoiding Ohmic losses, and achieving ultra-low power dissipation. Most of the envisioned magnonic logic devices are based on spin wave interference, where the minimum energy per operation is limited by the noise level. The sensitivity and selectivity of magnonic sensors is also limited by the low frequency noise. However, the fundamental question "do magnons make noise?" has not been answered yet. It is not known how noisy magnonic devices are compared to their electronic counterparts. Here we show that the low-frequency noise of magnonic devices is dominated by the random telegraph signal noise rather than 1/f noise - a striking contrast to electronic devices (f is a frequency). We found that the noise level of surface magnons depends strongly on the power level, increasing sharply at the on-set of nonlinear dissipation. The presence of the random telegraph signal noise indicates that the current fluctuations involve random discrete macro events. We anticipate that our results will help in developing the next generation of magnonic devices for information processing and sensing.