Thermodynamic properties of the exactly solvable transverse Ising model on decorated planar lattices

The generalized mapping transformation technique is used to obtain the exact solution for the transverse Ising model on decorated planar lattices. Within this scheme, the basic thermodynamic quantities are calculated for different planar lattices with arbitrary spins of decorating atoms. The particular attention has been paid to the investigation of the transverse-field effects on magnetic properties of the system under investigation. The most interesting numerical results for the phase diagrams, compensation temperatures and several thermodynamic quantities are discussed in detail for the ferrimagnetic version of the model.Comment: 9 pages, 13 figures, submitted to Journal of Magnetism and Magnetic Material

Monte Carlo Study of a Spin-3/2 Blume-Emery-Griffiths Model on a Honeycomb Lattice

We study the phase diagram of the spin-3/2 Blume-Emery-Griffiths model on a honeycomb lattice by Monte Carlo simulations in order to verify the presence of some peculiar features predicted by the effective field theory (EFT) with correlations. The locations of the order-disorder phase boundaries are estimated from thermal variations of the magnetic susceptibility curves. It is found that for positive values of the biquadratic interactions the critical boundary shows a discontinuous character as a function of the single-ion anisotropy strength, in line with the EFT expectations. However, for negative values of the biquadratic interactions the step-like variation of the critical frontier predicted by EFT was not reproduced.Comment: Submitted to conference proceedings CSMAG1

On the Ising-Heisenberg model with the doubly decorated network structure I

Using an exact mapping transformation method, magnetic properties of a spin-1/2 and spin-1 doubly decorated Ising-Heisenberg model are investigated in detail. By assuming that both interaction parameters are ferromagnetic, we found in addition to an usual ferromagnetic phase another two phases with a nontrivial long-range order.Comment: 3 pages, 2 figures, to be presented at conference ICM 200