Noise properties of a resonance-type spin-torque microwave detector

TL;DR

This paper investigates the noise characteristics of a resonance-type spin-torque microwave detector, identifying two operational regimes influenced by different noise sources, and provides a formalism for optimizing its noise performance.

Contribution

It introduces a formalism to analyze noise effects in a resonance-type spin-torque microwave detector, distinguishing two operational regimes and guiding noise optimization.

Findings

In high-frequency regime, SNR is proportional to input power.

In low-frequency regime, SNR is proportional to the square root of input power.

Performance limited by Johnson-Nyquist noise or magnetic noise depending on regime.

Abstract

We analyze performance of a resonance-type spin-torque microwave detector (STMD) in the presence of noise and reveal two distinct regimes of STMD operation. In the first (high-frequency) regime the minimum detectable microwave power $P_{\rm min}$ is limited by the low-frequency Johnson-Nyquist noise and the signal-to-noise ratio (SNR) of STMD is proportional to the input microwave power $P_{\rm RF}$. In the second (low-frequency) regime $P_{\rm min}$ is limited by the magnetic noise, and the SNR is proportional to $\sqrt{P_{\rm RF}}$. The developed formalism can be used for the optimization of the practical noise-handling parameters of a STMD.