The transverse mixed spin Ising model in a longitudinal random field

Abstract

The transverse mixed spin Ising system consisting of spin-1/2 and spin-1 with a longitudinal random field is studied within the finite cluster approximation based on single-site cluster theory. The equations are derived using a probability distribution method based on the use of Van der Waerden identities. In the absence of the transverse field, the complete phase diagram in the case of simple cubic lattice is investigated and exhibits interesting behaviours, where the longitudinal field is bimodally and trimodally distributed. The influence of the transverse field on these behaviours are also examined.