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 role of thermal fluctuations of shape (undulations) in reducing the effective rigidity of membranes is reviewed. The consequences of this effect on vesicle size distribution and on the structure of microemulsions, as well as on other physical phenomena, are sketched.

When DNA molecules are heated they undergo a denaturation transition by which the two strands of the molecule are separated and become unbound. Experimental studies strongly indicate that the denaturation transition is first order. The main theoretical approach to study this transition,...

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...

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...

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...

Exact expressions for the Curie temperature, magnetization, quadrupolar moment and the susceptibility of a spin-one Ising model on a Bethe lattice are derived. Biquadratic exchange and single-ion anisotropy are included, in addition to the bilinear exchange interactions. The variation of the...

The layer longitudinal magnetizations, their average, and both the longitudinal and the transverse susceptibilities of a diluted transverse spin-12 Ising film are studied within the framework of the effective field theory. The results show that the surface layer longitudinal magnetization can be...