Analysis of the Specific Heat for the Transitions of the Phases I-II-III-IV in (N(CH3)(4))(2)CUCl4 Crystal

YURTSEVEN H. H., Yardimci I.

HIGH TEMPERATURE MATERIALS AND PROCESSES, vol.27, no.3, pp.135-140, 2008 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 3
  • Publication Date: 2008
  • Journal Name: HIGH TEMPERATURE MATERIALS AND PROCESSES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.135-140
  • Middle East Technical University Affiliated: Yes

Abstract

The temperature dependence of the specific heat C-p is analyzed here using the experimental data according to a power-law formula with the critical exponent a for the transitions of commensurate (I), incommensurate (II) and the ferroelastic (III and IV) phases in (N(CH3)(4))(2)CUCl4 crystal. From our analysis, we extract the value of a approximate to 0 above and below T-c for the successive phase transitions of which is expected from the mean field theory (alpha =0 discontinuity), XY model (alpha =0 log) and the two dimensional Ising model (alpha =0 log). This indicates that the transitions between commensurate and incommensurate phases and also between incommensurate and ferroelastic (III) phases in TMATC-Cu are of a second order type.