Kavtanyuk Vladimir Vladimirovich, Lee Changjae, Jeong Keunhong, Shim Jeong Hyun
Quantum Magnetic Sensing Group, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
School of Biomedical Engineering, Korea University, Seoul, 02842, Republic of Korea.
Sci Rep. 2025 Mar 29;15(1):10896. doi: 10.1038/s41598-025-95675-7.
Optically polarizable nitrogen-vacancy (NV) centers in diamond enable hyperpolarization of C nuclear spins at a low magnetic field and room temperature. However, it remains a challenge to achieve a high level of polarization, comparable to that of conventional dynamic nuclear polarization. In this paper, we demonstrate that a C polarization of 5%, equivalent to an enhancement ratio of over [Formula: see text], can be attained at less than 10 mT. We used a high-purity diamond with an initial nitrogen concentration below 1 ppm, which resulted in a storage time exceeding 100 min. Aligning the magnetic field along [100] increased the number of NV spins involved in polarization transfer by a factor of four. For this orientation, a comprehensive optimization of the magnetic field intensity and microwave (MW) sweep parameters has been performed. The optimum MW sweep width suggests that polarization transfer occurs primarily to the bulk C spins through the integrated solid effect, followed by nuclear spin diffusion.
金刚石中的光学可极化氮空位（NV）中心能够在低磁场和室温下实现碳核自旋的超极化。然而，要实现与传统动态核极化相当的高水平极化仍然是一个挑战。在本文中，我们证明在小于10 mT的磁场下可以实现5%的碳极化，这相当于增强比超过[公式：见原文]。我们使用了初始氮浓度低于1 ppm的高纯度金刚石，其存储时间超过100分钟。将磁场沿[100]方向排列使参与极化转移的NV自旋数量增加了四倍。对于这个方向，已经对磁场强度和微波（MW）扫描参数进行了全面优化。最佳的MW扫描宽度表明，极化转移主要通过积分固体效应发生到体相碳自旋，随后是核自旋扩散。
