Ultrahigh nitrogen-vacancy center concentration in diamond

Kollarics, S.; Simón, F.; Bojtor, András; Koltai, K.; Klujber, G.; Szieberth, M.; Márkus, B. G.; Beke, D.L.; Gali, Ádám; Amirari, D.; Berry, R. Stephen; Boucher, S.; Gavryushkin, D.; Jeschke, Gunnar; Cleveland, J. P.; Takahashi, Susumu; Szirmai, Péter; Forró, Lászlø; Emmanouilidou, Eve; Singh, Rajeev; Holczer, K.

doi:10.1016/j.carbon.2021.12.032

Cited by 14 publications

(13 citation statements)

References 46 publications

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“…There are typically at least an order of magnitude more P1 centers in a diamond crystal than NV centers, 34 though the best efficiencies for converting P1 to NV centers can reach up to 20–25%. 35 , 36 As a consequence, most 13 C nuclear spins in diamond are much closer to a P1 center than an NV center, making the P1 centers potentially more efficient polarization sources. At high magnetic fields, DNP via P1 centers can produce a significant increase in nuclear spin polarization at cryogenic temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…The P1 center is a spin-1/2 substitutional nitrogen impurity in the diamond lattice that also exhibits long coherence and relaxation times, − though it is not optically active. There are typically at least an order of magnitude more P1 centers in a diamond crystal than NV centers, though the best efficiencies for converting P1 to NV centers can reach up to 20–25%. , As a consequence, most 13 C nuclear spins in diamond are much closer to a P1 center than an NV center, making the P1 centers potentially more efficient polarization sources. At high magnetic fields, DNP via P1 centers can produce a significant increase in nuclear spin polarization at cryogenic temperatures. ,− Bretschneider et al have also reported a room temperature 13 C DNP enhancement of 130 at 9.4 T under 8 kHz MAS conditions with 10 W of microwave power at 263 GHz .…”

Section: Introductionmentioning

confidence: 99%

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Large Room Temperature Bulk DNP of ¹³C via P1 Centers in Diamond

et al. 2022

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We use microwave-induced dynamic nuclear polarization (DNP) of the substitutional nitrogen defects (P1 centers) in diamond to hyperpolarize bulk 13 C nuclei in both single crystal and powder samples at room temperature at 3.34 T. The large (>100-fold) enhancements demonstrated correspond to a greater than 10 000-fold improvement in terms of signal averaging of the 1% abundant 13 C spins. The DNP was performed using low-power solid state sources under static (nonspinning) conditions. The DNP spectrum (DNP enhancement as a function of microwave frequency) of diamond powder shows features that broadly correlate with the EPR spectrum. A well-defined negative Overhauser peak and two solid effect peaks are observed for the central ( m I = 0) manifold of the 14 N spins. Previous low temperature measurements in diamond had measured a positive Overhauser enhancement in this manifold. Frequency-chirped millimeter-wave excitation of the electron spins is seen to significantly improve the enhancements for the two outer nuclear spin manifolds ( m I = ±1) and to blur some of the sharper features associated with the central manifold. The outer lines are best fit using a combination of the cross effect and the truncated cross effect, which is known to mimic features of an Overhauser effect. Similar features are also observed in experiments on single crystal samples. The observation of all of these mechanisms in a single material system under the same experimental conditions is likely due to the significant heterogeneity of the high pressure, high temperature (HPHT) type Ib diamond samples used. Large room temperature DNP enhancements at fields above a few tesla enable spectroscopic studies with better chemical shift resolution under ambient conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large Room Temperature Bulk DNP of ¹³C via P1 Centers in Diamond

et al. 2022

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“…For DC magnetic measurement [10] and AC magnetic measurement [11], the concentration of NV centers in diamond is one of the most relevant parameters [12]. In general, diamonds contain a certain concentration of natural NV centers which is sufficient for some applications [13], but most uses require much higher concentrations than those provided naturally [14][15]. Therefore, evaluating NV centers concentration plays an important role for NV centers in different scientific applications [16].…”

Section: Introductionmentioning

confidence: 99%

A Method of Evaluating NV centers Concentration by UV–Vis Transmittance Spectra

Zhang,

Zhang

et al. 2023

J. Phys.: Conf. Ser.

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The ultraviolet-visible (UV-Vis) spectrum was not generally considered an available method for measuring the concentration of negatively charged nitrogen-vacancy (NV-, NV center). In this study, we propose the idea of evaluating the concentration of NV center by the slope of the UV-Vis spectrum. To establish this new method we synthesized diamonds with different NV center concentrations by the chemical vapor deposition (CVD) method. We then measured the zero-phonon line (ZPL) intensity of PL spectra at 637 nm and estimated the concentration of the NV centers as a baseline for comparison to our new UV-Vis method. The UV-Vis transmission spectra were then measured and transformed to relative absorption coefficient spectra. Slopes of the transformed UV-Vis spectra between 400 nm and 800 nm were calculated and compared with the ZPL intensities. The results show a strong positive correlation between the slopes of the absorption spectra and the ZPL intensities of PL spectra at 637 nm. Therefore, this paper demonstrates the feasibility of estimating the concentration of the NV centers from measuring the transmission UV-Vis spectrum.

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“…Recently, a creation yield close to 1/100 has for example been reported for specific growth conditions on a [111] orientation [30]. High energy electron or neutron irradiation may also be used to introduce additional vacancies in the diamonds and thus convert part of the nitrogen in the sample into useful NV centres [25,31]. After annealing, yields up to 20 % have been reached.…”

Section: Introductionmentioning

confidence: 99%