Electron paramagnetic resonance in gamma-ray, electron and neutron flux irradiated sapphire

Zhang, Hailang; Zhang, M.F.; Hu, Zhaosheng; Han, Jiecai; Guo, Huaixin; Xu, Chao

doi:10.1016/j.nimb.2012.09.011

Cited by 5 publications

(5 citation statements)

References 24 publications

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“…The octahedral configuration has a predicted EFG in reasonable agreement with the observed ν Q , but the remaining discrepancy (∼ 12%) is substantially larger than for the 27 Al in pure α-Al 2 O 3 (without Li). DFT predictions of EFG tensors commonly overestimate the experimental values [32] with a lattice dynamic reduction being the primary candidate for the lower experimental ν Q .…”

Section: Resultssupporting

confidence: 63%

“…Radiation damage is known to produce paramagnetic defects in sapphire. The primary EPR signal is attributed to the F + color center with an electron trapped at an oxygen vacancy [27]. However, there is no missing amplitude evident in high field (see below), so if there is a paramagnetic fraction, it is not fast relaxing.…”

Section: Resultsmentioning

confidence: 99%

“…[14]. To further assess the reliability of the calculations, the same code and crystal structure was used to calculate C Q for stable 27 Al in pure α-Al 2 O 3 , yielding 2.305 MHz, in very good agreement with a recent experimental determination of 2.30(4) MHz [18]. Additional validation of the computational setup including the choice of the exchange-correlation functional and the numerical parameters can be found in the Supplemental Material (SM) [19].…”

Section: Calculationsmentioning

confidence: 99%

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The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

MacFarlane

Shenton²,

Salman³

et al. 2023

J. Phys.: Conf. Ser.

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We present high (> 2 T) magnetic field βNMR measurements of 8Li+ implanted in single crystals of sapphire, a commonly used backing material for other samples. From the well-resolved quadrupolar splitting, we extract the electric field gradient (EFG) at the implanted 8Li+ site. Comparison with supercell density functional theory calculations of the EFG allows us to identify the octahedral interstitial site as the most likely candidate. In contrast to the zero field βNQR spectra, where multiple singals are detected, only a single site is evident at high field. We discuss possible explanations for this discrepancy. The spin lattice relaxation is extremely slow (1/T 1 < 0.02 s−1 ) over a broad temperature range from 4 to 300 K, demonstrating that cross relaxation with the 27Al nuclear spins is quenched in such high magnetic fields.

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Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

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The Site and High Field βNMR Properties of ⁸Li⁺ Implanted in α-Al₂O₃

MacFarlane

Shenton²,

Salman³

et al. 2023

J. Phys.: Conf. Ser.

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“…G-factor of resonance absorption line at the magnetic field induction of 3363 G is equal to 1.97. In a number of papers, the EPR-signal with g=1.96-2.01 in alumina is associated with absorption of singly ionized oxygen vacancies [6]. The spectrum of single-crystal sample in addition to the main absorption line at the magnetic field 3492 G contained absorption lines at 2000 G and 5500 G, related to chromium ion impurities [7].…”

Section: Advances In Engineering Research Volume 110mentioning

confidence: 99%

Luminescent and Dosimetric Properties of Ultrafine Alumina Ceramics with Anion Defects

Ananchenko¹,

Кортов²,

Konev³

et al. 2017

Proceedings of the 3rd Annual International Conference on Advanced Material Engineering (AME 2017)

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Abstract. Ultrafine oxygen-deficient alumina ceramics was obtained by high-temperature annealing of nanopowder compacts in a vacuum in a strong reducing medium. The spectra of pulsed cathodoluminescence, photoluminescence, electron paramagnetic resonance and thermoluminescence of the synthesized ceramics and anion-defective Al2O3 single crystals were measured. Dose dependences of the thermoluminescence intensity on a dose of β-radiation were found.

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“…Its properties can be modified by point defects or extended defects produced by different type particle irradiation, such as electron, neutron and ion [4][5][6][7][8]. Due to its versatility [9,10], ion implantation or irradiation is the most favorable method used to modify the optical properties of sapphire.…”

Section: Introductionmentioning

confidence: 99%