Phase diagrams of the spin-5/2 Blume–Capel model.

We have used the Curie–Weiss mean-field approximation to study the effects of the random single-ion anisotropy and random magnetic field in the phase diagram and thermodynamic properties of the spin-5/2 Blume–Capel model. The phase diagrams have been presented in the temperature T ∕ J versus strength random single-ion anisotropy D ∕ J and strength random magnetic field h ∕ J planes. The magnetization dependence was plotted as a function of temperature and the strength single-ion anisotropy. These diagrams showed that the different phase transition types, first-or second-order between the ferromagnetic and paramagnetic phases, are dependent on the random parameters. Therefore, within these conditions, the model presents tricritical behavior. • Several phase diagrams were obtained for the spin-5/2 Blume–Capel model. • The influence of the random single-ion anisotropy and magnetic field was examined for the system. • First- and second-order phase transition lines were found. • The tricritical behavior was examined. [ABSTRACT FROM AUTHOR]