We present an experimental study of the longitudinal electron-spin relaxation of ensembles of negatively charged nitrogen-vacancy (NV−) centers in diamond. The measurements were performed with samples having different NV− concentrations and at different temperatures and magnetic fields. We found that the relaxation rate $T_{1}^{-1}$ increases when transition frequencies in NV− centers with different orientations become degenerate and interpret this as cross-relaxation caused by dipole-dipole interaction.

中文翻译：

---

金刚石中氮-空位团簇的纵向自旋弛豫

我们提出了对钻石中带负电荷的氮空位（NV-）中心的合奏进行纵向电子自旋弛豫的实验研究。使用具有不同NV-浓度且在不同温度和磁场下的样品进行测量。我们发现，当具有不同方向的NV−中心的跃迁频率退化时，弛豫率$ T_ {1} ^ {-1} $会增加，并将其解释为由偶极-偶极相互作用引起的交叉松弛。