Ground state phase diagrams for the mixed Ising 3/2 and 5/2 spin model

Ground state phase diagrams for the mixed Ising 2 and 5/2 spin model

“…2, where also are presented the equations of the coexistence lines that separate regions. These results contrast with the obtained results for the spins system (3/2, 5/2), this presents 6 different regions, 3 ferrimagnetics and 3 ferromagnetics [9], drastically altering the topology of the diagram. Table 1 shows the corresponding spin configurations of ground states and energies.…”

“…In a previous work based on ground state phase diagrams with 3/2 and 5/2 spin model, De La Espriella and Buendía argued that, although in [26] the Luttinger and Tisza conjecture is formally proved only for systems with next-nearest neighbors interactions that obey a simple physical symmetry. In the same paper the authors argue that this restriction is too strong and can be relaxed to include isotropic interactions along nearest neighbors and diagonals inside the unit cell as it is the case presented here [9], which coincides with our work. The ground state phase diagrams are generated by calculating the energy of each 2 Â 2 spin configuration, given by:…”

“…Are presented two regions, one ferromagnetic for J 0 1 > and a ferrimagnetic when J 0 1 < , with different spin configurations and the same ground state energy. The structure of the phase diagram is similar to the presented in the ground state phase diagram of the J 1 model studied by De La Espriella and Buendía for the mixed spins (3/2, 5/2) system [9]. Although the configurations of spins are different in both schemes, we note that for J 0 1 < , the phase is ferrimagnetic, while J 0 1 > is ferromagnetic.…”

“…The ground state phase diagrams may have several regions with different values of energy, spin configurations and multiphase points where can more than two phases coexist [9]. Around the multiphase points may emerge abundant critical phenomena, such as first order phase transitions and tricritical points [10,11].…”

Efecto de los Campos Cristalinos en un Ferromagneto de Ising Mixto Bidimensional

“…Estos materiales son una clase especial de magnetos moleculares, interesantes por la relativa facilidad de controlar sus propiedades durante los procesos de síntesis, mediante la selección deseada de fuentes de espín (Buendía y Villarroel, 2007;Ohkoshi y Hashimoto, 2002;Dely et al, 2009 En este trabajo desarrollamos simulaciones de Monte Carlo, técnica confiable en la solución de modelos de Ising mixto (Selke y Oitmaa, 2010;De La Espriella et al, 2012a;De La Espriella et al, 2012b;), para investigar las propiedades magnéticas de un modelo ferromagnético de Ising mixto de espines S i A = 3/2 y σ j B = 5/2, con distintos campos cristalinos. El modelo se ha estudiado por diversos métodos, entre los que se destacan las relaciones de recursión exacta (Yessoufou et al, 2009;Albayrak e Yigit, 2007), teoría de campo medio (Mohamad, 2011;Deviren y Keskin, 2010), Monte Carlo (De La Espriella y Buendía, 2011;De La Espriella y Buendía, 2010, De La Espriella et al, 2012a, teoría de campo efectivo (Zhang et al, 2005). En cada una de estas investigaciones se establece que el sistema presenta una rica variedad de fenómenos multicríticos, entre los que se destacan transiciones de fase de primer y segundo orden, temperaturas de compensación y comportamientos reentrantes.…”