Weak Magnetic Sensing via Floquet Driving in an Active Cavity Magnon Coupled System

TL;DR

This paper presents a room-temperature, PCB-implemented active cavity magnon system with Floquet modulation for highly sensitive weak magnetic field detection, achieving a 121 pT/b7Hz limit.

Contribution

It introduces a miniaturized, room-temperature magnetic sensor using Floquet driving in an active cavity magnon system with electrically tunable gain.

Findings

Achieved a magnetic field detection limit of 121 pT/b7Hz.

Enhanced quality factor and signal strength via electrically tunable gain.

Demonstrated effective weak magnetic field sensing at room temperature.

Abstract

While significant advancements have been made in weak magnetic field detection, conventional high-sensitivity techniques are often limited by requirements for cryogenic operation or bulky setups. In this work, we develop a sensitive alternating magnetic field sensor based on a coupled system of an active microwave cavity and yttrium iron garnet (YIG), with the components implemented on printed circuit boards (PCBs). By introducing electrically tunable gain to compensate for cavity losses, we substantially improve both the quality factor and the signal intensity. Under the coupled system, Floquet modulation is induced by the alternating magnetic field, allowing for weak field detection by driving a specific hybrid mode and measuring the resulting Floquet sidebands. This miniaturized device operates at room temperature, achieving a detection limit of 121 pT/\sqrt{Hz}.