
The general-spin Blume–Capel model: A study of the multicritical behavior using effective-field theory
2013; Elsevier BV; Volume: 393; Linguagem: Inglês
10.1016/j.physa.2013.09.003
ISSN1873-2119
AutoresEmanuel Costabile, J. Roberto Viana, J. Ricardo de Sousa, J. A. Plascak,
Tópico(s)Advanced Thermodynamics and Statistical Mechanics
ResumoThe general-spin Blume–Capel model is studied by using an effective-field theory with correlation. An expression for the free energy within the effective-field theory is proposed, and the complete phase diagram is constructed in the temperature and single-ion anisotropy plane. The first-order transition lines are obtained by Maxwell construction (comparison between free energies). Beyond first-order transitions at low temperatures, the results show second-order transitions and tricritical points, as well as a variety of double critical endpoints. The existence of the tricritical point and the number of critical endpoints strongly depend on the value of the spin.
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