High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry

TL;DR

This paper proposes a theoretical method to significantly enhance the sensitivity of NV magnetometers for detecting single nuclear spins at room temperature by using ferromagnetic resonance, enabling nanoscale NMR on biological samples.

Contribution

It introduces a novel setup with ferromagnetic resonance to amplify weak magnetic signals, achieving four orders of magnitude sensitivity improvement over current magnetometers.

Findings

Sensitivity improved by four orders of magnitude.

Single nuclear spin detection at 30 nm distance within one second.

Room temperature operation enables biological applications.

Abstract

We demonstrate theoretically that by placing a ferromagnetic particle between a nitrogen-vacancy (NV) magnetometer and a target spin, the magnetometer sensitivity is increased dramatically. Specifically, using materials and techniques already experimentally available, we find that by taking advantage of the ferromagnetic resonance the minimum magnetic moment that can be measured is smaller by four orders of magnitude in comparison to current state-of-the-art magnetometers. As such, our proposed setup is sensitive enough to detect a single nuclear spin at a distance of $30$~nm from the surface within less than one second of data acquisition at room temperature. Our proposal opens the door for nanoscale NMR on biological material under ambient conditions.