High-pressure magnetic transition in iron observed via diamond quantum sensing

TL;DR

This paper demonstrates high-pressure magnetic measurements in iron using diamond quantum sensors with NV centers, revealing a magnetic transition at pressures up to 30 GPa.

Contribution

The work introduces a novel method of using NV center ensembles on diamond anvils for magnetometry under high pressure, enabling direct observation of iron's magnetic transition.

Findings

Detected magnetic transition in iron at high pressure.

Achieved magnetic imaging up to 30 GPa.

Demonstrated the feasibility of diamond quantum sensing under extreme conditions.

Abstract

Diamond quantum sensors offer high precision and spatial resolution as magnetic probes, making them promising for a wide range of applications. While diamond anvil cells (DACs) can generate extremely high pressures, techniques for magnetometry under such conditions remain limited. By fabricating an ensemble of NV centers directly on the anvil diamond surface, we enable precise magnetic measurements under high pressure. In this work, we employ this NV ensemble to image the stray magnetic field of iron up to 30 GPa, enabling the observation of the magnetic transition ($\alpha$-$\varepsilon$ transition) in iron.