α-β inversion in quartz from low frequency electrical impedance spectroscopy

The alpha-beta phase transformation in quartz has been studied in the pressure range from 0.5 to 2.5 GPa by the use of the low frequency electrical impedance spectroscopy. The electrical conductivity data obtained at low frequencies exhibit a different slope on an Arrhenius plot ln(sigma(LFD)(*)T) vs. 1/T above and below T-c where T is the absolute and T-c is the inversion temperature. The point where the slope changes, coincide with the T-c i.e. the temperature point of alpha-beta inversion in quartz. The obtained inversion temperature T-c from this method compares well with the previous measurements of T-c using DTA and laser interferometry. The low frequency dispersion data in insulating materials with the ionic conductivity due to impurities may be a useful method for characterization of structural displacive phase transitions in quartz-like structures. (C) 2004 Elsevier Ltd. All rights reserved.