Structure and Dynamics of CaAl2O4 from Liquid to Glass: A High-Temperature 27Al NMR Time-Resolved Study

Massiot, Dominique; Trumeau, Dominique; Touzo, Bruno; Farnan, Ian; Rifflet, Jean-Claude; Douy, André; Coutures, Jean-Pierre

doi:10.1021/j100044a038

Cited by 72 publications

(79 citation statements)

References 4 publications

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“…. The area under the first peak gives an Al 3+ coordination number of 4.4±0.5 in good agreement with the NMR [30] and neutron scattering [24] measurements. The second Gaussian gives a Ca-O coordination number of 5.5±0.5.…”

Section: Structure Of Liquid Caal 2 Osupporting

confidence: 85%

Short- and intermediate-range order in levitated liquid aluminates

Hennet

Pozdnyakova

Cristiglio

et al. 2007

J. Phys.: Condens. Matter

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Abstract.We have used the aerodynamic levitation technique combined with CO 2 laser heating to study the structures of liquid CaAl 2 O 4 and MgAl 2 O 4 with x-ray and neutron diffraction. We determined the structure factors and corresponding pair correlation functions describing the short-and intermediate-range order in the liquids. The combination of the two scattering techniques makes it possible to derive information not accessible with a single measurement. In the case of the glass-forming liquid CaAl 2 O 4 we have made sequential measurements during free cooling to study the structural evolution during supercooling from the stable liquid phase to the cold glass below T g .

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Section: Structure Of Liquid Caal 2 Osupporting

confidence: 85%

Short- and intermediate-range order in levitated liquid aluminates

Hennet

Pozdnyakova

Cristiglio

et al. 2007

J. Phys.: Condens. Matter

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“…A way to limit the effect of the sample holder is to suppress it, by putting the sample (somewhat spherical) in equilibrium on a gas flow (Figure 2.12). This so-called aerodynamic levitation device was already instrumented on different spectroscopic tools [45,46]. It works well on solids as on liquids (a droplet in levitation), allows to control atmosphere via the choice of the sustaining gas, and is particularly interesting for glass-forming liquids as heterogeneous nucleation due to contact with the crucible is strongly limited.…”

Section: High-temperature Instrumentationmentioning

confidence: 99%

Optical Spectroscopy Methods and High‐Pressure–High‐Temperature Studies

Polian

Simon

Pagès³

2010

Thermodynamic Properties of Solids

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This chapter aims to show how optical spectroscopies contribute to the study of vibrational properties under extreme conditions. Now, what do we mean by extreme conditions? We can take it in the other way and mention that ambient conditions have nothing more special as to permit life on earth -that is already not bad! From the point of view of physics, no particular property occurs at ambient conditions. On the contrary, most of the matter in the universe is under extreme pressure (P) and temperature (T), as it is in planets, stars, and more exotic objects. Studies at high pressure and high temperature are hence only the study of matter in its normal conditions. The reason why geoscientists are much interested in such studies is self-explanatory, but other fields are widely studied. The application of high pressure and high temperature enables to explore the repulsive part of the potential energy (fundamental physics), to provoke phase transformations thereby leading to new structures eventually metastable at ambient conditions (materials sciences), to orient chemical reactions in requested directions (chemistry), and even to crystallize proteins, that otherwise would not happen by using other techniques (biology). Another interest to work under variable conditions is that, obviously, more insight is given into the considered phenomenon, in that the pressure and/or temperature derivatives of the phenomenon become available, thus offering a more complete picture to achieve optimum understanding and/or modeling.There are mainly five experimental methods to probe the vibrational properties of matter: optical spectroscopies (of main interest here), ultrasonics (US), inelastic neutron scattering (INS, cf. Chapter 3), more recently inelastic X-ray scattering (IXS, cf. Chapter 4) -that was made possible due to the introduction of third generation synchrotron radiation facilities -and picosecond (PS) acoustics.INS and IXS are used to determine the dispersion of vibration modes, that is, acoustical as well as optical ones, over the whole Brillouin zone (BZ). The most stringent limitations are the needed sources (national-size ones, i.e., a nuclear reactor for INS and a monochromatized X-ray beam as delivered by a synchrotron for IXS), and a limitation to small momentum transfer (q < 0.1q BZB , where q is the magnitude of the wavevector and BZB is the BZ boundary). An additional limitation for INS is

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“…Firstly, there is a reorganisation on quenching that leads to a reduction in the Al-O coordination number from 4.20(4) to 4.04(3), corresponding to a removal of the AlO 5 polyhedra and threefold-coordinated oxygen atoms that are present in the liquid, and the establishment of a network of corner-sharing AlO 4 tetrahedra in the glass. The liquid state coordination number of 4.20(4) compares to an estimate of 4.16 from high-temperature 27 Al NMR experiments, based on the temperature dependence of the chemical shift [19]. Secondly, edge-sharing Ca-centred polyhedra occur in the liquid, and there is an enhancement of these connections in the glass (Figure 3(b)).…”

Section: Structure Of Liquid and Glassy Calcium Aluminatesmentioning

confidence: 73%

Recent advances in identifying the structure of liquid and glassy oxide and chalcogenide materials under extreme conditions: a joint approach using diffraction and atomistic simulation

Kohara

Salmon

2016

Advances in Physics: X

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The advent of advanced instrumentation and measurement protocols makes it increasingly feasible to use X-ray and neutron diffraction methods to investigate the structure of liquid and glassy materials under extreme conditions of high-temperatures and/or high-pressures. In particular, a combination of diffraction and modern simulation techniques is allowing for an understanding of the structure of these disordered materials at both the atomistic and electronic levels. In this article, we highlight some of the recent work in solving the structure of liquid and glassy oxide and chalcogenide materials under extreme conditions. We consider, in turn, the use of aerodynamic levitation with laser heating to investigate the structure of high-temperature oxide melts and to fabricate novel glassy materials by container-less processing; the use of high-pressure methods in the gigapascal regime to investigate the mechanisms of network collapse for glassy network structures; and the simultaneous application of highpressures and high-temperatures to explore the structure of disordered materials. Finally, we consider the use of other quantum-beam diffraction-based techniques for probing the order hidden in the correlation functions that describe the structure of disordered matter.

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Structure and Dynamics of CaAl2O4 from Liquid to Glass: A High-Temperature 27Al NMR Time-Resolved Study

Cited by 72 publications

References 4 publications

Short- and intermediate-range order in levitated liquid aluminates

Short- and intermediate-range order in levitated liquid aluminates

Optical Spectroscopy Methods and High‐Pressure–High‐Temperature Studies

Recent advances in identifying the structure of liquid and glassy oxide and chalcogenide materials under extreme conditions: a joint approach using diffraction and atomistic simulation

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