All-diamond scanning probes for high-performance and robust nanoscale magnetometry

Nitrogen-vacancy (NV) centers in diamonds have emerged as a powerful platform for quantum sensing, enabling highly sensitive and quantitative measurements of magnetic fields both at room and cryogenic temperatures. To achieve nanoscale imaging resolution, scanning NV microscopy has been proposed and developed over the past decade to locally probe stray magnetic fields. This has enabled the revealing of nanoscale domains in multiferroics¹ and antiferromagnets², and even the imaging of a single electron spins³. More recently, such technology is being broadly explored as commercial products started to appear in the market.

At the core of this technology is an all-diamond scanning probe hosting a single NV center within a few tenths of nanometers from the tip apex⁴. In this work, the latest advancements in the fabrication and design of diamond scanning probes will be presented, including high resolution measurements with out-of-plane NV centers⁵, as well as measurements under high (>200 mT) bias fields using in-plane NV centers embedded into diamond probes. We also show that the speed and precision of scanning NV magnetometers can be improved by a factor of 6 by coupling the NV center to parabola-shaped scanning tips⁶. These developments will enable more robust, user-friendly, and reliable magnetometry measurements of a variety of materials at the nanoscale.

References:

¹ Nature 549, no. 7671 (2017): 252-256.

² Nano letters 19, no. 3 (2019): 1682-1687.

³ Nature Physics 9, no. 4 (2013): 215-219.

⁴ Nature nanotechnology 7, no. 5 (2012): 320-324.

⁵ Applied Physics Letters 115, no. 19 (2019): 192401.

⁶ Physical Review Applied 14, no. 6 (2020): 064007.