Critical behavior of the disorder-induced Raman modes close to the lambda-phase transition in NH4Cl


Yurtseven H., Kayisoglu D.

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol.58, no.8, pp.1823-1830, 2002 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 8
  • Publication Date: 2002
  • Doi Number: 10.1016/s1386-1425(01)00632-1
  • Title of Journal : SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
  • Page Numbers: pp.1823-1830

Abstract

This study gives our analysis of the disorder-induced Raman modes of v(7) (93 cm(-1)) and v. (144 cm(-1)) close to the lambda-phase transition (P = 0) in the NH4Cl crystal. We describe the critical behavior of the frequency shifts for those modes by a power-law formula and using our Raman data we obtain the value of 0.1 for the critical exponent which can also describe the critical behavior of the thermal expansivity and the specific heat of NH4Cl Close to its A-phase transition (T-lambda = 242.9 K). (C) 2002 Elsevier Science B.V. All rights reserved.