Abstract
Pulsed ESR experiments are reported for ensembles of negatively-charged nitrogen-vacancy centers (NV−) in diamonds at X-band magnetic fields (280–400mT) and low temperatures (2–70K). The NV− centers in synthetic type IIa diamonds (nitrogen impurity concentration <1 ppm) are prepared with bulk concentrations of 2 ⋅ 1013 cm−3 to 4 ⋅ 1014 cm−3 by high-energy electron irradiation and subsequent annealing. We find that a proper post-radiation anneal (1000°C for 60min) is critically important to repair the radiation damage and to recover long electron spin coherence times for NV−s. After the annealing, spin coherence times of T2=0.74ms at 5K are achieved, being only limited by 13C nuclear spectral diffusion in natural abundance diamonds. By measuring the temperature dependence of T2 in the under-annealed diamonds (900°C) we directly extract the density (1014−16 cm−3) and activation energy (2.5meV) of unannealed defects responsible for the faster NV− decoherence. At X-band magnetic fields, strong electron spin echo envelope modulation (ESEEM) is observed originating from the central 14N nucleus, and we extract accurate 14N nuclear hypefine and quadrupole tensors. In addition, the ESEEM effects from two proximal 13C sites (second-nearest neighbor and fourth-nearest neighbor) are resolved and the respective 13C hyperfine coupling constants are extracted.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.