Order-disorder phase transition in NH4AlF4


Yurtseven H., Yanik A.

JOURNAL OF PHASE EQUILIBRIA, vol.23, no.6, pp.502-505, 2002 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 6
  • Publication Date: 2002
  • Doi Number: 10.1361/105497102770331190
  • Title of Journal : JOURNAL OF PHASE EQUILIBRIA
  • Page Numbers: pp.502-505

Abstract

In this study we calculate the specific heat C-VI for NH4AlF4 due to the nearest-neighbor interactions between the NH4+ tetrahedra using an Ising model superimposed on an Einstein and/or Debye model. The specific beat C-VI calculated using a power-law formula is in good agreement with the observed C-P for the NH4AlF4 system. This is an indication that NH4AlF4 undergoes a weak first-order or a nearly second-order phase transition as predicted by our model.