Analysis of the IR-Raman Modes and the Heat Capacity Near the α-Inc-β Transitions in Quartz


YURTSEVEN H. H. , Günay E. , Karacali H., Ateş S.

Ferroelectrics, vol.577, no.1, pp.125-142, 2021 (Journal Indexed in SCI Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 577 Issue: 1
  • Publication Date: 2021
  • Doi Number: 10.1080/00150193.2021.1916356
  • Title of Journal : Ferroelectrics
  • Page Numbers: pp.125-142

Abstract

© 2021 Taylor & Francis Group, LLC.This study gives our analysis for the temperature dependence of the infrared frequency and the integrated intensity of the 695 cm−1 mode near the α–β transition at 847.5 K and the temperature dependence of the Raman scattering cross section of the 355 cm−1 mode near the β-INC (incommensurate) transition which occurs within a small temperature (∼1.3 K) interval in relation to the order parameter in quartz. Both analyses are performed according to a power–law formula for the order parameter (Formula presented.) with the critical index (Formula presented.) using the experimental data from the literature. We also analyze the temperature dependence of the heat capacity (Formula presented.) according to the renormalization–group expression including first-order corrections to scaling term close to the α-INC-β transitions in quartz by using the literature data. From our analyses, values of the critical exponent (Formula presented.) for the frequency and the integrated intensity of the 695 cm−1 infrared mode and for the Raman scattering cross section of the 355 cm−1 mode as a measure of the order parameter, are extracted. From the analysis of (Formula presented.) the values of the critical exponent (Formula presented.) are also extracted. Additionally, by means of scaling relations the critical exponent (Formula presented.) of the isothermal compressibility (Formula presented.) and the renormalized components ((Formula presented.) and (Formula presented.)) are predicted for the α-INC-β transitions in quartz. Our analyses given here indicate that weakly first-order transition occurs from the α phase to the incommensurate (INC) phase, which changes to the nearly second-order transition to the β phase with increasing temperature in quartz, as also observed experimentally.