Angle dependence of $^{15}$N nuclear spin dynamics in diamond NV centers

We report on the dynamics of the Rabi oscillation and the Larmor precession of $^{15}$N nuclear spin using nonselective short microwave pulses for initialization of $^{15}$N nuclear spins. We observe the Larmor precession of $^{15}$N nuclear spin depending on the angle between the applied magnetic field and the axis of the nitrogen vacancy center. We propose to utilize the change of the Larmor frequency of the nuclear spins to detect static magnetic fields at high sensitivity. Our results may contribute to enhancing the sensitivity of dc magnetic fields and devising novel protocols using $^{15}$N nuclear spin in nitrogen vacancy centers in diamonds.