Interaction of nitrogen-vacancy centers in diamond with a dense ensemble of carbon-13

The nitrogen-vacancy center in diamond attracts a lot of attention in sensing applications, mainly for temperature, magnetic field, and rotation measurements. Nuclear spins of carbon-13 surrounding the nitrogen-vacancy center can be used as a memory or sensing element. In the current work, a diamond plate with a relatively large concentration of carbon-13 was synthesized and examined. The spectrum of optically detected magnetic resonance was recorded and analyzed in a magnetic field range of 5-200 G. A strain-independent measurement technique of carbon-13 isotope concentration based on the analysis of magnetic resonance spectra was developed. Additionally, narrow features in the spectrum were detected and understood.