On the Paramagnetic Impurity Concentration of Silicate Glasses from Low-Temperature Physics

Bonfanti, Silvia; Jug, Giancarlo

doi:10.1007/s10909-015-1311-0

Cited by 10 publications

(22 citation statements)

References 33 publications

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“…Though unrecognized by the experimentalists, the heat capacity measured in some multi-component silicate glasses (pure, mono-component silica does not display such effect) has shown a strong dependence on the applied magnetic field. Such dependence was the first to be explained by the present approach [1,42]. The total TS heat capacity is easily evaluated for this model (ETM) and obtained from the above calculated DOS…”

Section: The Magnetic Field Dependent Specific Heatmentioning

confidence: 81%

“…3) and the resulting number of coherently tunneling particles making up each ATS diminishes with diminishing temperature. We have conducted an analysis of the paramagnetic magnetization of samples of Duran, BAS and BK7 glass reported in the literature as a function of temperature using the idea of the cell model and ATS tunneling in the interstices with a temperature-dependent N (T ) [42]. We have obtained in this way good fits to the data and an estimate of the Fe impurity concentrations that are in agreement with the concentrations extracted from the low-temperature C p data (Tables 1 and 3).…”

Section: Some Conclusion From the Magnetic Effects: Estimate Of Cellmentioning

confidence: 99%

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The Polycluster Theory for the Structure of Glasses: Evidence from Low Temperature Physics

Jug

2017

Springer Proceedings in Physics

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The problems of the intermediate-range atomic structure of glasses and of the mechanism for the glass transition are approached from the low-temperature end in terms of a scenario for the atomic organization that justifies the use of an extended tunneling model. The latter is crucial for the explanation of the magnetic and compositional effects discovered in non-metallic glasses in the Kelvin and milli-Kelvin temperature range. The model relies on the existence of multi-welled local potentials for the effective tunneling particles that are a manifestation of a non-homogeneous atomic structure deriving from the established dynamical heterogeneities that characterize the supercooled liquid state. It is shown that the extended tunneling model can successfully explain a range of experiments at low temperatures, but the proposed non-homogeneous atomic structure scenario is then tested in the light of available high resolution electron microscopy imaging of the structure of some glasses and of the behaviour near the glass transition.

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Section: The Magnetic Field Dependent Specific Heatmentioning

confidence: 81%

Section: Some Conclusion From the Magnetic Effects: Estimate Of Cellmentioning

confidence: 99%

The Polycluster Theory for the Structure of Glasses: Evidence from Low Temperature Physics

Jug

2017

Springer Proceedings in Physics

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“…22 and the extracted parameters in Table 11. We recall how we convert the Fe-concentrations thus obtained to atomic ppm concentrations (ppma), using the formula [50]:…”

Section: Bas Glassmentioning

confidence: 99%

Realistic tunnelling states for the magnetic effects in non-metallic real glasses

Jug

Bonfanti

Kob

2015

Philosophical Magazine

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The discovery of magnetic and compositional effects in the low temperature properties of multicomponent glasses has prompted the need to extend the standard two-level systems (2LSs) tunneling model. A possible extension [1] assumes that a subset of tunneling quasi-particles is moving in a threewelled potential (TWP) associated with the ubiquitous inhomogeneities of the disordered atomic structure of the glass. We show that within an alternative, cellular description of the intermediate-range atomic structure of glasses the tunneling TWP can be fully justified. We then review how the experimentally discovered magnetic effects can be explained within the approach where only localized atomistic tunneling 2LSs and quasi-particles tunneling in TWPs are allowed. We discuss the origin of the magnetic effects in the heat capacity, dielectric constant (real and imaginaryi parts), polarization echo and SQUID magnetization in several glassy systems. We conclude by commenting on a strategy to reveal the mentioned tunneling states (2LSs and TWPs) by means of atomistic computer simulations and discuss the microscopic nature of the tunneling states in the context of the potential energy landscape of glass-forming systems.arXiv:1508.02424v1 [cond-mat.dis-nn] 10 Aug 2015 1 IntroductionThe physics of glasses, especially at low temperatures, continues to attract considerable interest. At low temperatures glasses are believed to be characterized by low-energy excitations going under the name of tunneling systems, or states (TSs) which are normally described in terms of double-welled potentials (DWPs) and two-level systems (2LSs) with energy asymmetry and tunneling barrier uniformly distributed in the amorphous solid [2,3]. Little is still known about the nature of the TSs, but the general consensus is still that the intermediate-range atomic structure of glasses is well described by Zachariasen's 1932 continuous random network model [4,5] (thus, homogeneously disordered like for a liquid) and the 2LSs arise out of two slightly similar, localized atomic configurations. With this characterization the 2LSs have been employed in the 1970s and 80s to explain with some success the anomalies in the properties of glasses at low temperatures. Recently, the field has been witnessing a renaissance since the discovery that there are unexpected magnetic effects in insulating glasses [6,7,8,9] and that the TSs are responsible for the decoherence of phase qubits made of superconducting Josephson-junctions [10,11,12,13,14]. The 2LSs are thought to be ubiquitous in the junction's tunneling barrier which, though very thin, is considered to be amorphous and described by Zachariasen-Warren's model [4,5]. On the other hand, the low-temperature glasses have also been studied as a paradigm where to conduct research on the physics of aging so common to many disordered systems out of equilibrium [15,16]. In this context, the relevant degrees of freedom have also been described in terms of 2LSs, with some success [17]. Yet, deviations from the behaviour pred...

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“…Diamagnetic susceptibility is a comprehensive description of a magnetic moment for a free atom having atomic angular moment, electron spin, and diamagnetic response. Diamagnetic behavior is the change in the orbital angular momentum induced by an external magnetic field, and therefore, all materials exhibit a diamagnetic response [ 44 ]. Diamagnetic susceptibility is a property of all atoms in molecules and is proportional to the number of electrons and to the square of the radius of the orbit of a closed shell.…”

Section: Resultsmentioning

confidence: 99%

Ta2O5 Nanocrystals Strengthened Mechanical, Magnetic, and Radiation Shielding Properties of Heavy Metal Oxide Glass

2021

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In this study, for the first time, diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the structural, mechanical, magnetic, and radiation shielding of heavy metal oxide glasses. Transparent Ta2O5 nanocrystal-doped heavy metal oxide glasses were obtained, and the embedded Ta2O5 nanocrystals had sizes ranging from 20 to 30 nm. The structural analysis of the Ta2O5 nanocrystal displays the transformation from hexagonal to orthorhombic Ta2O5. Structures of doped glasses were studied through X-ray diffraction and infrared and Raman spectra, which reveal that Ta2O5 exists in highly doped glass as TaO6 octahedral units, acting as a network modifier. Ta5+ ions strengthened the network connectivity of 1–5% Ta2O5-doped glasses, but Ta5+ acted as a network modifier in a 10% doped sample and changed the frame coordination units of the glass. All Ta2O5-doped glasses exhibited improved Vicker’s hardness, magnetization (9.53 × 10−6 emu/mol), and radiation shielding behaviors (RPE% = 96–98.8%, MAC = 32.012 cm2/g, MFP = 5.02 cm, HVL = 0.0035–3.322 cm, and Zeff = 30.5) due to the increase in density and polarizability of the Ta2O5 nanocrystals.

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On the Paramagnetic Impurity Concentration of Silicate Glasses from Low-Temperature Physics

Cited by 10 publications

References 33 publications

The Polycluster Theory for the Structure of Glasses: Evidence from Low Temperature Physics

The Polycluster Theory for the Structure of Glasses: Evidence from Low Temperature Physics

Realistic tunnelling states for the magnetic effects in non-metallic real glasses

Ta2O5 Nanocrystals Strengthened Mechanical, Magnetic, and Radiation Shielding Properties of Heavy Metal Oxide Glass

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