Random crystal-field effects in a mixed spin-1/2 and spin-2 ferrimagnetic Ising system

Abstract

The magnetic properties of a mixed spin ferrimagnetic system σ = 1/2 and S = 2 at the sites of a square lattice with a random crystal field are studied by the mean field approximation. The ground state of the system is determined and the total magnetization is plotted according to the model parameters. Different behaviors for the thermal dependence of the magnetization are highlighted. In particular, one sees the appearance of one or two compensating points and many types of phase diagrams with first and second order phase transition lines as well as isolated critical and tricritical points.