Authors: Hamit YURTSEVEN, Selami SALİHOĞLU, Aytekin TÜBLEK
Abstract: For NH_4Br, there exist three phases; the disordered \beta, antiferro--ordered \gamma and ferro--ordered \delta phases. In this study, we expand the free energy in powers of the order parameter to obtain the phase diagram for NH_4Br. This expansion has been made around the triple and the tricritical point for NH_4Br. Our phase line equations have then been fitted to the experimental data. This gives that our calculated phase diagrams describe adequately the observed behavior of NH_4Br.