Effects of an external magnetic field on a mixed spin-3/2 and spin-5/2 Ising ferrimagnet: A Monte Carlo study

Abstract

The magnetic properties of a ferrimagnetic mixed spin‐3/2 and spin‐5/2 Ising model with two crystal fields, in a longitudinal magnetic field, are studied by Monte Carlo simulations. The role of the different interactions in the Hamiltonian is explored. We investigate the thermal variations of the total magnetization and present phase diagrams. Depending on the region of the parameter space, we find some interesting phenomena such as compensation temperatures, and discontinuities in the magnetizations. We find that when an external field is present, the discontinuities are due to a simultaneous reversal of the spins of the sublattices. They signal the change between two different antiferromagnetic orderings, and are basically due to a competition between the different interactions in the Hamiltonian. We plot the dependence of the temperature at which the new phase occurs, for the different parameters in the Hamiltonian. Our results differ radically from earlier results obtained by other authors based on mean field theories. We find compensation temperatures at some particular combinations of parameters. Mean field theory predicts a wide range of parameters where the system presents even several compensation temperatures; in most of these regions we found none. In contrast with the mean field analysis that only looks at the total magnetizations, our study includes an analysis of the behavior of the sublattice magnetizations.

Mixed Spin‐(3/2,7/2) Ising‐Type Ferrimagnet: Monte Carlo–Mean Field Treatment

“…This abrupt change in the magnetization has been observed in other ferrimagnetic models in the presence of external fields. [56,[81][82][83] In Figure 12 for T > T c the magnetization goes to zero since h 0 ¼ 0 and all the jM T j curves in Figure 13 have the same saturation value as they should. The discontinuity in the magnetization at T k is due to a sudden simultaneous reversal of the spins of both sublattices as shown in Figure 14 where we plot the sublattice magnetizations.…”

Random-anisotropy mixed-spin Ising on a triangular lattice

“…There are a lot of studies carried out with different combinations of spins, such as exact solutions [8][9][10][11] for the simplest combination spin-1/2 and 1. Moreover, the mixed-spin Ising model has been studied by different approaches such as mean-field approximation [12][13][14][15][16][17], effective-field theory [18][19][20][21], renormalization group [22], numerical Monte Carlo simulations [23][24][25][26][27].…”

Monte Carlo Simulation of a Mixed Spin‐1/2 and Spin‐3/2 Ising Ferrimagnetic System with Site Dilution

“…Mixed Ising models constitute a useful tool to explore a rich variety of phenomena such as critical behavior, [ 18,19 ] compensation temperatures, [ 20–22 ] hysteresis loops, [ 23,24 ] reentrant behavior, [ 25,26 ] remanent magnetization, [ 27 ] superparamagnetism, [ 28 ] etc. [ 29,30 ] There are many theoretical works that have contributed to the magnetic characterization of various mixed models and lattice structures, such as spin systems (2, 5/2), [ 31,32 ] (3/2, 5/2), [ 33,34 ] (1/2, 5/2), [ 35 ] (2, 3/2), [ 36 ] (1/2, 1), [ 37–39 ] (1, 3/2), [ 40 ] and (1, 2), [ 41 ] to just mention a few. The most common techniques to study these models are mean and effective field theories and numerical simulations based on Monte Carlo techniques.…”