Effect of uniaxial single-ion anisotropy upon magnetic properties of a mixed spin-1/2 and spin-S (S⩾1) Ising model on a bathroom tile (4–8) lattice is examined within the framework of an exact star-triangle mapping transformation. Particular attention is focused on the phase diagrams...

The possibility of a diffuse interface of an Ising model on a Cayley tree with four nearest neighbors is illustrated using the unstable solution of the one-phase problem. The pinning of the domain wall is caused by a weakening influence from this solution in favor of the bulk one.

A mixed-spin Ising model on a decorated Bethe lattice is rigorously solved by combining the decoration–iteration transformation with the method of exact recursion relations. Exact results for critical lines, compensation temperatures, total and sublattice magnetizations are obtained from a...

We develop a transfer matrix method to compute exactly the spin–spin correlation functions for Bethe lattice Ising model and Blume–Emery–Griffiths (BEG) model in the external magnetic field h and for any temperature T. The correlation length ξ(T,h) obtained from the spin–spin...

Within the framework of the effective-field theory with correlations, the ferromagnetism of spin-32 Ising model with a transverse crystal field on honeycomb and square and simple cubic lattices is studied. Tricritical phenomena have been observed for the square and simple cubic lattices, but...

The ferromagnetic spin-1 Ising model with a transverse crystal field is studied within the framework of the effective field theory on honeycomb, square and cubic lattices. We have investigated the effect of the transverse crystal field on the magnetization and quadrupolar moments, and phase...

We study the phase diagram for the Ising model on a Cayley tree of arbitrary order k with competing nearest-neighbor interactions J1, prolonged next-nearest-neighbor interactions Jp, and one-level k-tuple neighbor interaction Jo. The phase diagram is studied for several ranges of the competing...

The spin-1/2 Ising model on a square lattice, with fluctuating bond interactions between nearest neighbors and in the presence of a random magnetic field, is investigated within the framework of the effective field theory based on the use of the differential operator relation. The random field...

We study the phase diagrams for the Ising model on a Cayley tree-like lattice, called Triangular Chandelier, with competing nearest-neighbour interactions J1, prolonged next-nearest-neighbour interactions Jp and one-level next-nearest-neighbour quadruple interactions Jl1. The phase diagrams...

The Ising model in the presence of a random field is investigated within the mean field approximation based on Landau expansion. The random field is drawn from the asymmetric and anisotropic bimodal probability distribution P(hi)=pδ(hi−h0)+qδ(hi+λ∗h0), where the site probabilities p,q...