Mixed-spin Ising model and compensation temperature

Abstract

We presented a study of the magnetic properties of a mixed-spin Ising ferrimagnetic model on a hexagonal lattice. The lattice is formed by alternate layers of spins $\ensuremath{\sigma}=1/2$ and $S=1.$ For this spin arrangement, any spin at one lattice site has two nearest-neighbor spins on the same sublattice, and four on the other sublattice. The intersublattice interaction is antiferromagnetic. The compensation point is a special point that appears below the critical temperature, for which the sublattice magnetizations cancel each other. We employed mean-field calculations and Monte Carlo simulations to find the compensation point of the model. The role of the different interactions in the Hamiltonian is explored. When the intrasublattice interaction for the $\ensuremath{\sigma}$ spins exceeds a minimum value, which depends on the other parameters of the Hamiltonian, a compensation point is possible. We have also shown that the phase diagram in the plane magnitude of $S\ensuremath{-}S$ exchange interactions versus crystal-field intensity exhibits a very narrow region of compensation points.