Phase diagrams of the spin-2 Ising model in the presence of a quenched diluted crystal field distribution

Abstract

We have investigated the random crystal field effects on the phase diagrams of the spin-2 Blume—Capel model for a honeycomb lattice using the effective-field theory with correlations. To do so, the thermal variations of magnetization are studied via calculating the phase diagrams of the model. We have found that the model displays both second-order and first-order phase transitions in addition to the tricritical and isolated points. Reentrant behavior is also observed for some appropriate values of certain system parameters. Besides the usual ground-state phases of the spin-2 model including ±2, ±1, and 0, we have also observed the phases ±3/2 and ±1/2, which are unusual for the spin-2 case.