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...

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 trimodal probability distribution P(hi)=pδ(hi−h0)+qδ(hi+h0)+rδ(hi), where the probabilities p,q,r take on values within the...

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 bimodal probability distribution P(h)=pδ(h−h0)+(1−p)δ(h+h0), where the probability p assumes any value within the interval...

Properties of semi-infinite (S=1) Heisenberg ferromagnet with biquadratic exchange were studied in terms of surface exchange (ε=IS/I) and biquadratic coupling (a). It was shown that a strict correlation exists, depending on ε, between the type of surface spin waves (acoustic or optical) and...

Data compressors available in the web have been used to determine magnetic phases for two-dimensional (2D) systems [E. Vogel, G. Saravia, F. Bachmann, B. Fierro, J. Fischer, Phase transitions in Edwards-Anderson model by means of information theory, Physica A 388 2009 4075–4082]. In the...

The Ising model in a transverse field, which involves quantum tunneling in double potential wells, has been used for many years to describe ferroelectric phase transitions. An alternative model previously published takes into account the effect of a non-negligible zero-point energy in the double...

The specific Gibbs free energy has been calculated for the infinite range Ising model with fixed and finite interaction strength. The model shows a temperature driven first-order phase transition that differs from the infinite ranged Ising model with weak coupling. In the temperature-field phase...

In this work we study an axial next-nearest neighbor Ising (ANNNI) model with spin 1 and crystal-field anisotropy. We discuss its properties and construct its phases diagrams within the mean-field approximation. In particular, we show that modulated phases with zero magnetization planes, or...

Phase transitions of the mixed spin- 1/2 and spin-S (S≥1/2) Ising model on a three-dimensional (3D) decorated lattice with a layered magnetic structure are investigated within the framework of a precise mapping relationship to the simple spin- 1/2 Ising model on a tetragonal lattice. This...

In their comment to the paper “Theory of the evaporation/condensation transition of equilibrium droplets in finite volumes” [Physica A 319 (2003) 99], Biskup et al. claim that in finite systems at fixed density “the physical significance of the conjugate thermodynamic variable is of...