The role of exchange interaction in nitrogen vacancy centre-based magnetometry

TL;DR

This paper explores how exchange interactions between nitrogen vacancy centers in diamond and a ferromagnetic heterostructure can significantly influence magnetometry, especially at sub-nanometer distances, opening avenues for advanced spintronic applications.

Contribution

It introduces a multilayer device design and highlights the importance of exchange interactions in NVC-based magnetometry at very close proximities, a factor often overlooked.

Findings

Exchange energy can surpass magnetostatic energy at 1-2 nm proximity.

Exchange interactions increase exponentially as the distance decreases below 1 nm.

Potential for spintronic applications beyond magnetometry, such as detecting spin-Hall effects.

Abstract

We propose a multilayer device comprising of a thin-film-based ferromagnetic hetero-structure (FMH) deposited on a diamond layer doped with nitrogen vacancy centers (NVC's). We find that when the NVC's are in close proximity (1-2 nm) with the FMH, the exchange energy is comparable to, and may even surpass the magnetostatic interaction energy. This calls for the need to consider and utilize both effects in magnetometry based on NVC's in diamond. As the distance between the FMH and NVC is decreased to the sub-nanometer scale, the exponential increase in the exchange energy suggests spintronic applications of NVC beyond magnetometry, such as detection of spin-Hall effect or spin currents.