Specific heat calculated from the Raman frequency shifts close to the gimel-phase transition in NH4Br

Yurtseven H., Yanik A.

HIGH TEMPERATURES-HIGH PRESSURES, no.3, pp.321-327, 2003 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2003
  • Doi Number: 10.1068/htjr070
  • Journal Name: HIGH TEMPERATURES-HIGH PRESSURES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.321-327
  • Middle East Technical University Affiliated: Yes

Abstract

We calculated the specific heat C-VI close to the lambda-phase transition in NH4Br on the basis of predictions of the Ising model. We have used our observed Raman frequencies of the nu(5) (134 cm(-1)) lattice mode to extract the critical exponent for the specific heat. The C-VI values calculated by us with this exponent value agree with the measured C-P data reported in the literature. This agreement is particularly good above T-lambda. This indicates that the observed behaviour of NH4Br can be satisfactorily explained close to the lambda-phase transition in this crystal.