High-temperature phase transitions and elasticity of silica polymorphs |
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| Authors: | Dmitry L Lakshtanov Stanislav V Sinogeikin Jay D Bass |
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| Institution: | (1) Department of Geology, University of Illinois at Urbana-Champaign, 1301 W Green St., Urbana, IL 61801, USA |
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| Abstract: | The single-crystal acoustic velocities of α- and β-quartz were measured by Brillouin spectroscopy to a maximum temperature
>1,500°C at room pressure. From these velocities, the single-crystal elastic moduli were calculated up to 1,050°C, exceeding
the temperature range of previous measurements by 350°C for the elastic moduli and by 710°C for acoustic velocities. The ordinary
refractive index (n
o) of α- and β-quartz was measured from room temperature to 800°C. In the temperature interval from ∼950 to 1,000°C a subtle
change in the temperature derivative of the longitudinal acoustic velocity was observed in platelet geometry for all measured
directions. The high-temperature acoustic velocity data may indicate the presence of a second phase, presumably β-cristobalite,
that nucleates below 1,000°C.
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| Keywords: | Quartz Cristobalite Elastic constants High temperature Phase transitions Brillouin scattering |
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