Review of some experiments in the 50 year saga of the E′ center and suggestions for future research

Weeks, R. A.; Magruder, R.H.; Stesmans, André

doi:10.1016/j.jnoncrysol.2007.06.080

Cited by 42 publications

(28 citation statements)

References 48 publications

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“…That assignment did fit in naturally with the theoretically calculated E 1 ' model (Weeks et al, 2008) depicting the defect in crystalline a quartz as the O 3 ≡Si.+Si≡O 3 unit when in the paramagnetic state. The E' precursor is seen as a diamagnetic O 3 ≡SiH paramagnetic center which upon hole trapping releases a mobile proton leading to the formation of a paramagnetic O 3 ≡Si≡E' defect, as detected by ESR.…”

Section: Introductionsupporting

confidence: 67%

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Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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The thermal properties such as Gibbs free energy, activation energy, entropy and enthalpy have been evaluated from the absolute number of spins of E 1 ' in gamma-ray-irradiated and as-is amethysts. It is for the first time to calculate the above properties for E 1 ' in amethyst. The Gibbs free energy of E 1 ' increases with the decrease of temperature from 296 K to 90 K. The activation energy and pre-exponential coefficients of E 1 ' have been evaluated from the logarithmic number of spins and the reciprocal of temperature plot. The Curie temperature and Curie constant of E 1 ' have been evaluated from the reciprocal of magnetic susceptibility and temperature plot. The exchange field, exchange integral and exchange interaction energy have been evaluated from the Curie temperature.

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Section: Introductionsupporting

confidence: 67%

“…Agnello et al (2002) have suggested that there are two structures for the E' center and a new variety of E' center was reported in 2006. The E' center concentration in natural crystals and silica is used to measure the age of geological specimens (Weeks et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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“…Numerous studies have focused on the oxygen vacancies created during irradiation [1,[14][15][16]. Indeed, it is well-known that the oxygen vacancies present in quartz after ionization or electronic radiations can trap electrons, forming the so-called E center, a color center that modifies the optical properties of quartz [17]. This has been used to assess, by optical techniques, the level of damage and the threshold displacement energy (E d ) [1,14], a critical quantity commonly used to estimate radiation damage [18].…”

Section: Introductionmentioning

confidence: 99%

Nature of radiation-induced defects in quartz

Wang

Pignatelli

et al. 2015

The Journal of Chemical Physics

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Although quartz (α-form) is a mineral used in numerous applications wherein radiation exposure is an issue, the nature of the atomistic defects formed during radiation-induced damage have not been fully clarified. Especially, the extent of oxygen vacancy formation is still debated, which is an issue of primary importance as optical techniques based on charged oxygen vacancies have been utilized to assess the level of radiation damage in quartz. In this paper, molecular dynamics (MD) simulations are applied to study the effects of ballistic impacts on the atomic network of quartz. We show that the defects that are formed mainly consist of over-coordinated Si and O, as well as Si-O connectivity defects, e.g., small Si-O rings and edge-sharing Si tetrahedra. Oxygen vacancies, on the contrary, are found in relatively low abundance, suggesting that characterizations based on E centers do not adequately capture radiation-induced structural damage in quartz. Finally, we evaluate the dependence on the incident energy, of the amount of each type of the point defects formed, and quantify unambiguously the threshold displacement energies for both O and Si atoms. These results provide a comprehensive basis to assess the nature and extent of radiation damage in quartz.

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“…For the implementation of SSTFM, Payne et al [9] suggested to use a crystalline silicon (c-Si) scanning probe tip with an amorphous silicondioxide (SiO 2 ) film in which a single E' center [14][15][16][17] would be used as probe spin, located at the apex. E' centers exhibit positive correlation energies and are therefore paramagnetic, a property that allows them to be studied with electron paramagnetic resonance (EPR) spectroscopy [18,19].…”

Section: Introductionmentioning

confidence: 99%

“…Few studies have focused on the dynamic properties of this spin s = 1/2 system, but those that have show that E' centers exhibit remarkably long longitudinal (T 1 ) spin relaxation times over large temperature ranges [17,[20][21][22][23]. At room temperature, T 1 times on the order of hundreds of microseconds have been reported [22].…”

Section: Introductionmentioning

confidence: 99%

Spin-Relaxation Dynamics ofE′Centers at High Density inSiO2Thin Films for Single-Spin Tunneling Force Microscopy

et al. 2015

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The suitability of the spin-dynamics of paramagnetic silicon dangling bonds (E' centers) in high E'-density amorphous silicon dioxide (SiO2) as probe spins for single-spin tunneling force microscopy (SSTFM) is studied. SSTFM is a spin-selection rule based scanning-probe single-spin readout concept. Following the synthesis of SiO2 thin films on (111) oriented crystalline silicon substrates with room-temperature stable densities of [E ] > 5×10 18 cm −3 throughout the 60nm thin film, pulsed electron paramagnetic resonance spectroscopy was conducted on the E' centers at temperatures between T = 5K and T = 70K. The measurements revealed that the spin coherence (the transverse spin-relaxation time T2) of these centers is significantly shortened compared to low-E' density SiO2 films and within error margins not dependent on temperature. In contrast, the spin-flip times (the longitudinal relaxation times T1) are dependent on the temperature but with much weaker dependence than low-density SiO2, with greatest deviations from low-density SiO2 seen for T = 5K. These results, discussed in the context of the spin-relaxation dynamics of dangling bond states of other silicon-based disordered solids, indicate the suitability of E' centers in high-density SiO2 as probe spins for SSTFM.

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Review of some experiments in the 50 year saga of the E′ center and suggestions for future research

Cited by 42 publications

References 48 publications

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Nature of radiation-induced defects in quartz

Spin-Relaxation Dynamics ofE′Centers at High Density inSiO2Thin Films for Single-Spin Tunneling Force Microscopy

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