Nanoscale magnetic imaging of single spins using NV centers in diamond

P. Maletinsky* (1), M. S. Grinolds* (2), S. Hong* (2), M. D. Lukin (2), R. L. Walsworth (2), A. Yacoby (2)

(*) equally contributing
(1) Department of Physics, University of Basel, Switzerland
(2) Department of Physics, Harvard University, Cambridge, USA

The study of magnetism has led to numerous fundamental discoveries and technological advances over the last decades. Today, the exploration of novel magnetic phenomena and materials is partly hindered by the difficulty to detect weak magnetic fields with nanometer spatial resolution. Recently, the Nitrogen-Vacancy (NV) center in diamond has been identified as an efficient nanoscale magnetic field sensor, which could relax these limitations and enable magnetic imaging with a unique combination of high field sensitivity and spatial resolution [1,2].
Here, we present our recent experimental achievements in such NV-based nanoscale magnetic field imaging. In particular, we will describe our approach to scanning probe magnetometry, which consists of using an all-diamond scanning-probe tip, containing a single NV-center, for magnetic field sensing [3]. Our scannable NV centers achieve magnetic sensitivities <50nT/sqrt(Hz) and imaging resolutions <25nm as determined by imaging domains of a magnetic memory medium.
To further demonstrate the unprecedented performance of our NV magnetometer, we present an experiment where we applied our apparatus to magnetic imaging of the dipole field of a single electron spin under ambient conditions. Achieving this ultimate performance goal for a nanoscale magnetometer has been an outstanding challenge for decades and will enable numerous applications in nanosciences and technology in the future.

[1] G. Balasubramanian et al., Nature 455, 648 (2008).
[2] J. Maze et al., Nature 455, 644 (2008).
[3] P. Maletinsky, et al., Nature Nanotechnology 7, 320 (2012).