Nanoscale Nuclear Magnetic Resonance with a Nitrogen-Vacancy Spin Sensor

Nanoscale NMR with Diamond Defects Although nuclear magnetic resonance (NMR) methods can be used for spatial imaging, the low sensitivity of detectors limits the minimum sample size. Two reports now describe the use of near-surface nitrogen-vacancy (NV) defects in diamond for detecting nanotesla magnetic fields from very small volumes of material (see the Perspective by Hemmer ). The spin of the defect can be detected by changes in its fluorescence, which allows proton NMR of organic samples only a few nanometers thick on the diamond surface. Mamin et al. (p. 557 ) used a combination of electron spin echoes and pulsed NMR manipulation of the proton spins to detect the very weak fields. Staudacher et al. (p.…