Effect of Longitudinal Electron Spin Relaxation on Transverse Nuclear Spin Relaxation in a Nitrogen-Vacancy Center in Diamond

Nitrogen-vacancy (NV) color centers in diamond serve as a unique platform for various types of quantum sensors, including a nuclear magnetic resonance gyroscope. The fundamental sensitivity limit of a quantum sensor is closely related to the free precession dephasing time T_2n^* of the nuclear spin. The dependence of T_2n^* and transverse relaxation time T_2n on the magnetic field at room temperature in the field range from 2 to 8 G is investigated, demonstrating that T_2n^* and T_2n are not limited by the longitudinal relaxation time T_1e of the electron spin projection.