CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si35.svg"><mml:msub><mml:mi>B</mml:mi><mml:mn>1</mml:mn></mml:msub></mml:math> evaluation in EPR and DNP enhanced NMR spectroscopies

Rakvin, Boris; Carić, Dejana; Kveder, Marina

doi:10.1016/j.jmro.2022.100039

Cited by 2 publications

(12 citation statements)

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“…The spectra were recorded by employing Bruker ER 4118X-MD5 microwave cavity with 200 mW source of microwave radiation. The cavity conversion constant for converting microwave power into 𝐵 1 field was obtained earlier [10]. Magnetic field modulation with magnetic modulation frequency of (𝜔 𝑟𝑓 2𝜋 ⁄ = 100 kHz) and small modulation amplitude (1µT, corresponding to 𝜔 2 2𝜋 ⁄ ~27 kHz in frequency units) was applied for all monitored EPR spectra.…”

Section: Methodsmentioning

confidence: 99%

“…It was shown that for the first harmonic of phasesensitive detection spectrum detected 90 o out-of-phase with respect of the modulation frequency (out-of-phase spectrum) shows inversion of MS lines while passing Rabi resonance condition (𝜔 1 = 𝜔 𝑟𝑓 ) during the saturation process [12]. The detection of this effect in the close vicinity of Rabi resonance enables the estimation of 𝐵 1 ≈ 3.6 µT for applied magnetic field modulation frequency of (𝜔 𝑟𝑓 2𝜋 ⁄ = 100 kHz) [10].…”

Section: Introductionmentioning

confidence: 98%

“…Determination of the intensity of the microwave (MW) magnetic field (𝐵 1 ) in spectroscopic techniques such as electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) in combination with the method of dynamic nuclear polarization (DNP) is one of the important parameters for further application of these techniques. In a continuous wave (CW) EPR spectroscopy the intensity of 𝐵 1 traditionally can be determined by applying several methods [1][2][3][4][5][6][7][8][9][10][11]. Recently, two methods [9,10] have been proposed for 𝐵 1 calibration using P1 (Ns 0 ) nitrogen centers in commercial high pressure high temperature (HPHT) diamond as a suitable calibration standard in EPR spectroscopy as well as in non-resonant structures such as DNP-enhanced NMR.…”

Section: Introductionmentioning

confidence: 99%

“…In a continuous wave (CW) EPR spectroscopy the intensity of 𝐵 1 traditionally can be determined by applying several methods [1][2][3][4][5][6][7][8][9][10][11]. Recently, two methods [9,10] have been proposed for 𝐵 1 calibration using P1 (Ns 0 ) nitrogen centers in commercial high pressure high temperature (HPHT) diamond as a suitable calibration standard in EPR spectroscopy as well as in non-resonant structures such as DNP-enhanced NMR. For the later techniques it is important to note that one should chose as a standard the sample with long spin-spin (𝑇 2 ) and spin-lattice (𝑇 1 ) relaxation times as is expected for P1 (Ns 0 ) centers even at room temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…The origin of different relaxation times was related to electron-electron spin diffusion mechanism and electron-electron dipolar coupling which contribute to the line broadening. The most recent method [10] proposed HPHT type-IIa diamond crystal containing low concentration of P1 (Ns 0 ) centers ([Ns 0 ] <1ppm)…”

Section: Introductionmentioning

confidence: 99%

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Study of microwave magnetic field saturation properties of an inhomogeneous CW-EPR line in the vicinity of Rabi resonance: Possible application for B 1 estimation

Rakvin,

Jurec

2024

Preprint

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The spectrum of continuous wave electron paramagnetic resonance (CW-EPR) was analyzed with respect to the shape of the line under microwave (MW) power saturation (\({P}_{MW}\sim{B}_{1}^{1/2};{B}_{1 }\)is intensity of MW magnetic field). The used \({B}_{1 }\) increases until the Rabi frequency \(({\omega }_{1}=\gamma {B}_{1}\), \(\gamma\)is the electron gyromagnetic ratio) approaches the radiofrequency \(\left({\omega }_{rf}\right)\) used as the magnetic modulation frequency. The possible effect of Rabi resonance \(\left({\omega }_{1}={\omega }_{rf}\right)\), on spin packets system can be detected under the condition of “weak modulation near the Rabi resonance” (\({\omega }_{2}\ll {\omega }_{1}\approx {\omega }_{rf})\) where \({\omega }_{2}\) is modulation amplitude of radiofrequency field expressed in frequency units. Inhomogeneously broadened, CW-EPR, lines of the P1 (Ns0) nitrogen centers (30ppm>[Ns0] <200ppm) in diamond crystal and E’ defect in irradiated vitreous SiO2 with long spin relaxation times (\({T}_{1}\) and \({T}_{2}\)ranged in the interval from around 2ms to 1 µs at room temperatures) were selected for saturation study. Spectra were recorded using magnetic field modulation \(({\omega }_{rf}/2\pi =100\) kHz) with modulation amplitude\(({\omega }_{2}/2\pi =27 \text{k}\text{H}\text{z})\) as the first harmonic for two phase-sensitive detections, detection in-phase with respect to the modulation frequency and detection 90o out-of-phase with respect of the modulation frequency. The resulting changed in inhomogeneous spectral lines of P1 and E’ centers detected near Rabi resonance in the saturation process shows that both samples can be used as a standard for estimation \({B}_{1}\) value.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%