Ferrimagnetism and compensation temperature in spin-1/2 Ising trilayers

Abstract

The mean-field and effective-field approximations are applied in the study of magnetic and thermodynamic properties of a spin-1/2 Ising system containing three layers, each of which is composed exclusively of one out of two possible types of atoms, A or B. The A-A and B-B bonds are ferromagnetic while the A-B bonds are antiferromagnetic. The occurrence of a compensation phenomenon is verified and the compensation and critical temperatures are obtained as functions of the Hamiltonian parameters. We present phase diagrams dividing the parameter space in regions where the compensation phenomenon is present or absent and a detailed discussion about the influence of each parameter on the overall behavior of the system is made. * ianlopezdiaz@gmail.com † nsbranco@fisica.ufsc.br 2

Compensation temperature in spin-1∕2 Ising trilayers: A Monte Carlo study

“…Nonetheless, the quantitative results are significantly different in all cases. Namely, in the same way the EFA values for the critical temperatures are consistently lower than those for the MFA [53], the same is true for the MC estimates, which are lower than both the EFA and MFA ones.…”

“…Our MC calculations can be compared to the EFA and MFA results reported in Ref. 53 for the same model. For instance, the qualitative behavior displayed in our Fig.…”

“…5(b) in Ref. 53) ones. Nonetheless, the quantitative results are significantly different in all cases.…”

“…Among the few examples found in the literature, we mention an alternating spin-1/2, -1, and -3/2 Ising three-layered superlattice which was studied both in a mean-field approach [50] and through MC simulations [51]. We also cite a spin-1/2 Ising hexagonal lattice trilayer analyzed within the EFA [52] and a spin-1/2 Ising square lattice trilayer analyzed within both the MFA and the EFA [53].…”

“…This model has already been analyzed in Ref. 53 within the MFA and EFA approaches, however, although mean-field-like approximations usually provide a fast and qualitatively right solution for most models, they do not always describe the actual physical behavior of some low-dimensional systems (see Ref. 54 and references therein).…”