The diluted mixed-spin transverse Ising system with longitudinal crystal field interactions

The diluted mixed-spin transverse Ising system consisting of spin-1/2 and s pin-1 with crystal held interactions is studied by the use of an effective field method within the framework of a single-site cluster theory. The stat e equations are derived using a probability distribution method based on th e use of Van der Waerden identities. The complete phase diagrams are invest igated in the case of the honeycomb lattice. Ln particular, the influence o f the crystal field interactions and the concentration of magnetic sites ar e examined in detail. We find that the system exhibits a variety of interes ting features, especially near the percolation threshold. (C) 2000 Elsevier Science B.V. All rights reserved.