Specific heat of NH4Br and NH4BrxCl1-x crystals close to the antiferroelectric transition
JOURNAL OF APPLIED PHYSICS, vol.98, no.9, 2005 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 98 Issue: 9
- Publication Date: 2005
- Doi Number: 10.1063/1.1989427
- Journal Name: JOURNAL OF APPLIED PHYSICS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Middle East Technical University Affiliated: Yes
Abstract
We calculate the specific heat C-VI of NH4Br and mixed crystals of NH4BrxCl1-x using the Ising model for the transition between the disordered (D) and antiferro- (AF) electric phases in these crystalline systems. Our C-VI values, which we calculated for x(Br)=1, 0.26, and 0.51 are in good agreement, both below and above T-C, with the observed C-P data from the literature. Our value of congruent to 0.1 (T < T-C and T>T-C) for the critical exponent of the specific heat agrees with the value of 0.125 predicted by a three-dimensional Ising model.