Magnetometry and Stress Tomography in Diamond Anvil Cells using Nitrogen Vacancy Centers

The Nitrogen Vacancy (NV) center in diamond has emerged as a promising candidate for the nanoscale sensing of temperature, strain, electric and magnetic fields. The integration of NV-based sensing into diamond anvil cells (DAC), a workhorse of high pressure science, offers a means not only for making spatially resolved measurements of relevant sample properties but also for monitoring the stress distribution in the diamond anvil itself. Compared to conventional high pressure probes, key advantages of NV sensing include diffraction limited spatial resolution (~ 1 um) and versatility, thus enabling exploration of novel phases of matter and the transitions between them, with pressure as a tuning parameter. Additionally, imaging the stress distribution inside DACs can provide insight into the mechanical failure of anvils and inform improvements in anvil design. We describe two main results: 1) we generate a layer of NVs near the tip of the diamond anvil and use DC magnetometry to study pressure-driven magnetic phase transitions and 2) using a carefully applied bias magnetic field we map the tensorial stress distribution within the diamond anvil itself.