An anomaly in the β phase near the α-β transition of quartz

Abstract

2014 Des mesures détaillées de dilatation thermique, de module d'élasticité et de biréfringence, en phase 03B2, près de la transition (1er ordre) 03B1-03B2 du quartz révèlent une anomalie qui suggère l'existence d'une transition du 2e ordre à une température légèrement supérieure à celle de la transition 03B1-03B2. Abstract. 2014 Detailed measurements of thermal expansion, elastic compliance and birefringence in the 03B2 phase of quartz around the 03B1-03B2 first order transition show an anomaly which suggests the existence of a second order transition slightly above the usual 03B1-03B2 transition.

α-β Transition in Quartz: Temperature and Pressure Dependence of the Thermodynamic Quantities for β-Quartz and β-Cristobalite as Piezoelectric Materials

“…Measurements of the heat capacity [9,10,25], dielectric constant [26] and thermal expansion [2] have been conducted for the a-b transition in quartz. Spectroscopic techniques such as the Raman scattering [29,31,32], infrared [30], light scattering [11,27] X-ray and neutron diffraction [9,10,22,33,36,37] have been used to investigate the a and b structures in quartz.…”

Dynamics of the ?-? phase transitions in quartz and cristobalite as observed by in-situ high temperature 29Si and 17O NMR

“…Since it was first observed by La Chatelier (1889), the c~-fi phase transition in quartz has been intensively studied using a wide variety of techniques. There has been a renewed interest in the phase transition, and in particular its mechanism and dynamics, since the discovery of the incommensurate phase (INC) in quartz by Bachheimer (1980). It is now known that the "classic" second-order e-fi phase transition in quartz is actually two transitions: the first-order c~-INC transition, and the second order INC-//transition, separated by about 1.8 ~ C (Hatta et al 1985).…”

Optical studies of the incommensurate phase of quartz

“…In the first measurements either by birefringence (Bachheimer, 1980) or by neutron scattering (Dolino et al, 1983) the transition at 7;. appeared to be rather continuous.…”

“…As presented in this The cc-p transition of quartz at 849 K was discovered one century ago by Le Chatelier (1889) who also performed the first optical studies of this transition by measuring the optical activity (Le Chatelier, 1890) and the birefringence (Mallard and Le Chatelier, 1890). However, it was only 90 years later that Bachheimer (1980) observed a change of slope in the thermal expansion and in the birefringence at a temperature 7;: (1.4 K above the transition temperature upon cooling) showing the existence of a new phase. The inc character of this phase was soon confirmed by the observation of satellite peaks by neutron diffraction (Dolino et al, 1983) and by X-ray diffraction (Gouhara et al, 1983) as previously predicted in the theoretical work of Aslanyan and Levanyuk (1979).…”