Phase diagram and tricritical behavior of an Ising metamagnet model in a trimodal random field

The phase diagram of an Ising metamagnet in a random magnetic field is studied by using mean-field equations from Bogoliubov's variational principle. The trimodal probability distribution is applied. The phase diagram in the t-h plane presents continuous and first-order transition lines. The phase transition lines, together with the critical points, were obtained for several random field values.