Room temperature DNP of diamond powder using frequency modulation

Shimon, Daphna; Cantwell, Kelly A.; Joseph, Linta; Ramanathan, Chandrasekhar

doi:10.1016/j.ssnmr.2022.101833

Cited by 4 publications

(4 citation statements)

References 31 publications

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“…Based on previous findings at lower magnetic fields, , we wished to examine the efficiency of 13 C hyperpolarization at 6.9 and 13.8 T and investigate which mechanisms are involved. In particular, we wanted to confirm that the strong on-resonance DNP effect assigned to OE/tCE at 3.3 T is still present at higher magnetic fields.…”

Section: Resultsmentioning

confidence: 99%

“…P1 centers are spin S = 1 2 paramagnetic centers with long coherence times at room temperature, and have been studied by EPR spectroscopy for decades. − They can serve as a very efficient source of 13 C hyperpolarization in dynamic nuclear polarization (DNP) experiments. Recently, a detailed analysis of DNP mechanisms in a powder of HPHT microdiamonds was carried out by decomposing the DNP spectra acquired at 3.3 T. , One of the most intriguing outcomes of this analysis was the significant DNP enhancement on-resonance with the P1 EPR transitions. Such on-resonance DNP is either due to the Overhauser effect (OE) or due to the recently proposed truncated cross-effect (tCE) .…”

Section: Introductionmentioning

confidence: 99%

“…Based on previous findings at lower magnetic fields, 22,23 we wished to examine the efficiency of 13 C hyperpolarization at 6.9 and 13.8 T and investigate which mechanisms are involved.…”

Section: ■ Introductionmentioning

confidence: 99%

“… 28 It is therefore unclear which species give rise to this effect. Shimon et al hypothesized the presence of P1 center clusters, 21 , 22 but a proof is yet to be provided. The existence of such clusters has also been proposed by Nunn et al based on continuous-wave (CW) EPR power saturation.…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen Substitutions Aggregation and Clustering in Diamonds as Revealed by High-Field Electron Paramagnetic Resonance

Nir-Arad,

Shlomi,

Manukovsky

et al. 2023

J. Am. Chem. Soc.

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Diamonds have been shown to be an excellent platform for quantum computing and quantum sensing applications. These applications are enabled by the presence of defects in the lattice, which are also known as color centers. The most common nitrogen-based defect in synthetic diamonds is the paramagnetic nitrogen substitution (P1) center. While the majority of quantum applications rely on nitrogen-vacancy (NV) centers, the properties of the latter are heavily influenced by the presence and the spatial distribution of the P1 centers. Hence, understanding the spatial distribution and mutual interactions of P1 centers is crucial for the successful development of diamond-based quantum devices. Unlike NV centers, P1 centers do not have a spin-dependent optical signature, and their spin-related properties, therefore, have to be detected and characterized using magnetic resonance methods. We show that using high-field (6.9 and 13.8 T) pulsed electron paramagnetic resonance (EPR) and dynamic nuclear polarization (DNP) experiments, we can distinguish and quantify three distinct populations of P1 centers: isolated P1 centers, weakly interacting ones, and exchange-coupled ones that are clustered together. While such clustering was suggested before, these clusters were never detected directly and unambiguously. Moreover, by using electron−electron double resonance (ELDOR) pump−probe experiments, we demonstrate that the latter clustered population does not exist in isolation but coexists with the more weakly interacting P1 centers throughout the diamond lattice. Its presence thus strongly affects the quantum properties of the diamond. We also show that the existence of this population can explain recent hyperpolarization results in type Ib high-pressure, high-temperature (HPHT) diamonds. We propose a combination of high-field pulsed EPR, ELDOR, and DNP as a tool for probing the aggregation state and interactions among different populations of nitrogen substitution centers.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Based on previous findings at lower magnetic fields, 22,23 we wished to examine the efficiency of 13 C hyperpolarization at 6.9 and 13.8 T and investigate which mechanisms are involved.…”

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nitrogen Substitutions Aggregation and Clustering in Diamonds as Revealed by High-Field Electron Paramagnetic Resonance

Nir-Arad,

Shlomi,

Manukovsky

et al. 2023

J. Am. Chem. Soc.

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Dynamic Nuclear Polarization with P1 Centers in Diamond

Palani,

Mardini,

Quan

et al. 2024

J. Phys. Chem. Lett.

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Substitutional nitrogen impurities within the diamond lattice, known as P1 centers, have unpaired electrons that can mediate microwave driven dynamic nuclear polarization (DNP). In this paper we explore DNP of the bulk 13 C spins in micrometer-sized P1 diamond particles and demonstrate a 550fold DNP enhancement of the bulk 13 C spins at room temperature in a 9 T magnetic field or 250 GHz for g ≈ 2 electrons. We study the DNP mechanisms, exploring their dependence on sample spinning frequency and microwave irradiation frequency using both continuous wave and frequency swept microwave irradiation, and discuss the results alongside recent DNP studies in the literature. Even with a modest microwave irradiation power of 160 mW from our frequency swept solid-state microwave source, we achieve a significant 13 C signal enhancement, ε = 270 at room temperature. The enhancements were found to increase with the magic angle spinning (MAS) frequency, ω r /2π, and the results provide mechanistic insights into how different electron populations contribute to the observed DNP efficiency. These findings are inherently interesting and of practical importance in view of the recently reported diamond rotors fabricated from P1 high-pressure, high-temperature (HPHT) diamond.

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Hyperpolarisation techniques

Equbal,

Mewis

2023

Nuclear Magnetic Resonance

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This chapter focuses on the literature published in 2022, covering hyperpolarisation techniques associated with NMR. The literature reviewed relates to the hyperpolarisation techniques of dynamic nuclear polarisation (DNP), spin-exchange optical pumping (SEOP), parahydrogen induced polarisation (PHIP) and signal amplification by reversible exchange (SABRE). In addition to reviewing studies that have been conducted using these techniques, a number of reports are discussed that relate to advances in associated hardware and instrumentation.

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Room temperature DNP of diamond powder using frequency modulation

Cited by 4 publications

References 31 publications

Nitrogen Substitutions Aggregation and Clustering in Diamonds as Revealed by High-Field Electron Paramagnetic Resonance

Nitrogen Substitutions Aggregation and Clustering in Diamonds as Revealed by High-Field Electron Paramagnetic Resonance

Dynamic Nuclear Polarization with P1 Centers in Diamond

Hyperpolarisation techniques

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