The phase diagram and paramagnetic susceptibility of the spin 32 Blume-Capel model are investigated within the statistical accuracy of the Bethe-Peierls approximation (or the correlated effective field treatment). In particular, the inverse paramagnetic susceptibility may show an outstanding...

The magnetic properties of a decorated Ising system with a random field at the decorated atom are investigated by the use of the effective-field theory with correlations. In particular, the phase diagram and magnetization curve of the decorated ferrimagnetic honeycomb lattice are examined...

The phase diagram of magnetic thin films with decorated surfaces is studied by the use of the decoupling approximation within the framework of the differential operator technique in Ising systems. The formulation is at first discussed for the semi-infinite spin-12 Ising ferromagnetic system with...

The magnetic properties (phase diagram, magnetization curve, spin correlation functions, internal energy and magnetic specific heat) of a decorated ferrimagnetic square lattice composed of three magnetic atoms are investigated on the basis of the differential technique. The system can show many...

A method that applies to a wide class of the random-field Ising models is used to investigate the influence of random-field on the critical phenomena. The 3D random-field Ising models with nearest-neighbour interactions exhibit tricritical behavior. The obtained results express rather large...

A new correlated effective-field theory of spin-one Ising systems, namely the Blume-Capel and Blume-Emery-Griffiths models, is developed, using exact Ising spin identities, the Honmura-Kaneyoshi differential operator technique and the concept of correlated effective field. In particular, the...

Surface phase diagrams of a spin-one monolayer on a semi-infinite spin-12 ferromagnet are investigated by using a version of the effective-field theory. In particular, the effects of the surface biquadratic exchange interaction on the surface phase diagram are discussed. Some characteristic...

The phase diagrams of the semi-infinite Ising ferromagnet with decorated magnetic (spin-S) and nonmagnetic atoms on the surface are investigated within the framework of the effective-field theory. In particular, the critical properties of the special point in the surface phase diagram are...

A new effective-field theory for the Blume-Capel model with a high spin value S is developed by making use of exact spin identities and taking advantage of the differential operator technique. The general formulation for evaluating the transition line and the tricritical point is derived. In...

A new type of effective-field theory that has recently been used with success for many applications concerning the two-state transverse Ising model (spin-12 TIM), is herein extended to the spin-1 TIM. The method, which can explicitly and systematically include correlation effects, is illustrated...