Using a generalization of the VLP technique to spin-phonon systems the effect of spin-phonon interactions on the magnetic excitations of an S=1 Heisenberg ferromagnet having both exchange and single-ion anisotropy is studied. The calculations are carried out using a semi-invariant expansion of...

The magnetization of an anisotropic cubic spin-one Ising model with single-ion anisotropy is studied using a linear chain approximation. In particular, for several ratios, η, between the interchain and intrachain exchange interactions the critical temperatures of the second and first order...

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 theoretical study of the spin 2 Ising ferromagnet with site dilution in a transverse field is presented using an effective field method within the framework of a single site cluster theory. The effective field equations are derived using a probability distribution method based on the use of...

The quenched site-diluted spin-52 Blume-Capel model is studied using a new technique in effective field theory that employs a probability distribution within the framework of single-site cluster theory based on the use of exact Ising spin identities. The probability distribution, derived with...

A theoretical study of the transverse Ising model with arbitrary spin is presented using an extension of an effective field theory that has recently been inroduced for studying general spin S Ising models. In the theory, the effective field equations are derived using a probability distribution...

The effective field equations for diluted spin S Ising models are derived using a probability distribution method based on the use of generalized Van der Waerden identities. The approach is employed within the framework of a single-site cluster theory based on the use of exact Ising spin...

The present paper deals with the statistical mechanics of an asymmetrical Ising mounted on the Bethe lattice. An asymmetrical Ising model is defined by assuming the spin variable of the usual Ising Hamiltonian to take up the eigenvalues 1, − λ, where λ is an asymmetry parameter. It is shown...

The critical behaviour of the generalized Ising model is studied using the power series coherent anomaly method. We work with the eleven-terms susceptibility series of Oitmaa and Enting. Taking the inverse of this series and studying the coherent anomalies we arrived at the results for Curie...

The zero-field high temperature static susceptibility series of the spin-S nearest-neighbour Ising model on simple cubic (SC), body-centred cubic (BCC) and face-centred cubic (FCC) lattices is thoroughly analysed by means of a power series coherent anomaly method (CAM). Our analysis revealed...