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

Abstract

Mean field and Monte Carlo simulations techniques are applied to study the behavior of a mixed Ising spin model in a square lattice where spins 7/2 are located in alternating sites with spins 3/2. There is an antiferromagnetic interaction between nearest neighbors, ferromagnetic interactions between next-nearest neighbors, crystal fields, and a magnetic external field. The role of the different interactions in the magnetic behavior of the system is explored. It is found that depending on the combination of parameters in the Hamiltonian this system presents multiple hysteresis loops, exchange bias, compensation temperatures, and discontinuous magnetizations. The results are compared with previous studies that do not include the ferromagnetic next-nearest neighbor interactions and found that they can have a strong effect in the magnetic behavior of the system.

Hysteresis and Double‐Spin Compensation Behaviors in a Ferro‐Ferrimagnetic Model of High Half‐Integer Spins

“…Comparing our results with the ref. [14], it can be seen that for ferromagnetic exchange interactions and positive anisotropies ( and ), with , the authors did not find compensation points. They found only one point for and (see Figure 12 [ 14 ] ).…”

“…[14], it can be seen that for ferromagnetic exchange interactions and positive anisotropies ( and ), with , the authors did not find compensation points. They found only one point for and (see Figure 12 [ 14 ] ). Despite studying the same spin configuration, in this investigation, we obtained different results, considering antiferromagnetic couplings to second neighbors in the B sublattice () and negative single‐ion anisotropy in the A sublattice ().…”

“…Through Monte Carlo (MC) simulations, the effects of the parameters are reflected in the phase diagrams of the magnetization and susceptibility of the system and are framed in the behavior of multiple hysteresis cycles, double‐spin compensation temperature (), and discontinuities (). It should be noted that this paper can be considered to be a continuation of the work done by De La Espriella et al [ 14 ] on the same spin configuration, but now applying antiferromagnetic couplings of next‐nearest neighbors in the B sublattice of spins. In other words, we consider this research to be a complement to the referenced study in ref.…”

“…[ 29 ] Recently, De La Espriella et al, using mean‐field and MC theories, found that the model also experiences discontinuities in the magnetization. [ 14 ]…”

Efectos de anisotropía de ion simple sobre un sistema ferrimagnético de espines enteros

“…Aparentemente el análisis termomagnético de un sistema de espines enteros, como el ferrimagneto tipo Ising con redes de momentos magnéticos 𝑆 = 1 y 𝜎 = 2, pareciera que no tiene importancia porque aún no se ha reportado en la literatura, hasta donde conocemos, ningún compuesto o material que contenga este tipo de espines o esté estructurado con ellos. Pero este trabajo se justifica por la variedad de fenómenos físicos que hemos hallado en este modelo, por ejemplo puntos de compensación (Tcomp), es decir temperaturas por debajo de la temperatura crítica (Tc) a la cual la magnetización total es cero, pero el sistema permanece ordenado (De La Espriella et al, 2019;De la Espriella et al, 2021;Kageyama et al,2003); transiciones discontinuas y continuas, las primeras muy útiles en las grabaciones magneto-ópticas y de gran interés práctico en el almacenamiento de datos magnéticos y su manipulación (Ostler et al, 2012;Barker et al, 2013) y las segundas, eficientes en la determinación de la transición de la fase ferrimagnética a la fase paramagnética, cuando el material se halla totalmente desordenado (De La Espriella et al, 2021). Además, los resultados teóricos obtenidos podrían servir como base de futuras investigaciones experimentales sobre compuestos con la configuración espintrónica 𝑆 = 1 y 𝜎 = 2.…”