EPR study of crystalline and vitreous forms of the Li2OAl2O3SiO2 system

Grunin, V. S.; Ioffe, V. A.; Yanchevskaya, I.S.; Zonn, Z.N.

doi:10.1016/0022-3093(74)90094-5

Cited by 8 publications

(2 citation statements)

References 2 publications

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“…For samples C and D, we used g⊥ = (gxx + gyy)/2 and A⊥ = (Axx + Ayy)/2. octahedral symmetry around V 4+ ion is improved in the second EPR signal [28].…”

Section: H G βH S G β H S H S a I S A I S I Smentioning

confidence: 91%

“…In these glasses, the V 4+ ion appears almost exclusively as a vanadyl form, VO 2+ [25][26][27]. EPR has been successfully employed in glass research because the VO 2+ EPR spectra is easily observable until room temperature and the spin-Hamiltonian parameters, such as the g-tensor and the hyperfine coupling A-tensor are sensitive to the local environment around a paramagnetic species and the changes in the coordination geometry and ligand binding resulting from, for example, thermal treatments of glasses [28][29][30]. X-band and Q-band CW EPR spectra of V 2 O 5 -doped SbPO 4 -GeO 2 glasses and samples heat treated at temperatures between glass transition and onset of crystallization were reported here.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and structural characterization of a new SbPO4-GeO2 glass system

Montesso

Manzani

Donoso

et al. 2018

Journal of Non-Crystalline Solids

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This work presents the production and characterization of a new prolific binary glass system based on SbPO 4-GeO 2. The dependence of GeO 2 content on thermal, structural and optical properties were investigated by means of thermal analysis, Raman, UV-Vis-NIR, infrared, M-lines and EPR spectroscopy. Glass transition temperatures remain constant around 410°C when GeO 2 content is increased, indicating that GeO 4 units are not responsible for increasing the connectivity of PO 4 units. Thermal stability linearly increases as a function of GeO 2 content, reaching a value around 400°C for glass containing 90 mol% of GeO 2. Raman spectroscopy was used to evaluate the glass structural changes when GeO 2 is incorporated from 30 to 90 mol% indicating a gradual change from a phosphate to a germanate glass skeleton. The optical window extends from 350 nm at UV region, up to 2.7 μm in the middle-infrared region limited by the multiphonon cutoff due to the strong OH absorption. M-lines technique shows that increasing GeO 2 content decreases the refractive index, mainly because the lower concentration of higher polarizable antimony atoms. EPR spectra of heat treated V 2 O 5 doped glasses, at different temperatures above the glass transition temperature, shows the characteristic eight-line hyperfine splitting spectrum. The spin Hamiltonian parameters obtained from the simulated spectra indicates that the paramagnetic tetravalent vanadium ions in the glasses exist as vanadyl form VO 2+ , located in axially distorted octahedral sites. For glasses treated at higher temperatures a second VO 2+ component appears in the EPR spectra and the analysis of the spin-Hamiltonian parameters suggests that these vanadyl ions are in more tetragonal distorted octahedral sites than those in the glass.

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“…For samples C and D, we used g⊥ = (gxx + gyy)/2 and A⊥ = (Axx + Ayy)/2. octahedral symmetry around V 4+ ion is improved in the second EPR signal [28].…”

Section: H G βH S G β H S H S a I S A I S I Smentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Synthesis and structural characterization of a new SbPO4-GeO2 glass system

Montesso

Manzani

Donoso

et al. 2018

Journal of Non-Crystalline Solids

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Coloured Synthetic zircon crystals. Flux growth and EPR of V4+ impurity centres

Ball

Wanklyn

1976

Phys. Stat. Sol. (a)

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The growth of blue and green zircon (ZrSiO4) crystals from fluxes consisting of (PbO + V2O5) and (3 Bi2O3 + V2O5), respectively, is reported. Vanadium is found in the crystals and EPR experiments show that it occurs, at least in part, as V4+ in sites of tetragonal symmetry. EPR is observed at X‐and Q‐band frequencies at temperatures of 20 and 4.2 K. The hyperfine constants are anisotropic and A‖ shows a marked temperature dependence. The spin Hamiltonian parameters at 20 K are g⊥ = 1.8930 ± 0.0008, A‖ = (81.6 ± 0.2) × X 10−4 cm−1, g⊥ = 1.9699 ± 0.0008, A‖ = (28.9 ± 0.2) × 10−4 cm−1. At 4.2 K: A‖ = (84.1 ± 0.2) × 10−4 cm−1.

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