Critical behaviors of bond and crystal field dilution Blume-Emery-Griffiths model

The critical behavior of the spin-1 bond and crystal field dilution Blume-Emery-Griffiths model have been investigated on simple-cubic lattice within the framework of the effective field theory. In particular, both bond dilution and random crystal field are considered at the same time. The interplay between bond and crystal field dilution constructs rich and interesting phase diagrams. Significant distinctions are exhibited. When positive ratio a changes in a certain range, there exist double tricritical points in phase-transition lines in T-D plane. Moreover, this first-order phase transition is enlarged with increasing of ratio a at a fixed crystal field dilution concentration, while this first-order phase transition will shrink when bond dilution concentration is fixed. In addition, we observe that there exist two bond percolation thresholds for negative crystal field and alpha > 0 in T-P plane. (c) 2006 Elsevier B.V. All rights reserved.