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

Abstract

Temperature and pressure dependencies of the thermal expansivity (αp), isothermal compressibility (κT) and the specific heat (Cp − Cv) are studied for piezoelectric materials, in particular, for β-quartz. By analyzing the temperature (at 1 atm) and pressure (at 848 K) dependence of the observed volume V from the literature, the thermodynamic functions (αp, κT and Cp − Cv) are obtained and the Pippard relations (Cp − Cv vs. Vαp and αp vs. κT) close to the transition from the β-quartz to the β-cristobalite are examined.