Brillouin-Scattering Study of Sound Velocity of Quartz at α-ß Transition
It is well known that quartz (SiO2) undergoes the first-order phase transition at 573°C from the lower temperature trigonal (α) phase to the higher-temperature hexagonal (ß) phase accompanying an anomaly in the velocity of a particular acoustic phonon. But the mechanism of the transition has not been fully understood. In this paper we propose a mechanism of the transition based on the elastic constants derived from Brillouin scattering. The measurements were carried out at temperatures up to 700°C with emphasis on the propagation direction dependence in three principal planes as well as their temperature dependence.
KeywordsSound Velocity High Temperature Phase Acoustic Phonon Principal Plane Phonon Velocity
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