%0 Journal Article
%T The Possibility of Many Compensation Points in a Mixed-Spin Ising Ferrimagnetic System
%A Hadey K. Mohamad
%J ISRN Condensed Matter Physics
%D 2013
%R 10.1155/2013/759450
%X The magnetic properties of a ferrimagnetic mixed spin-3/2 and spin-5/2 Ising model with different anisotropies are investigated by using the mean-field approximation (MFA). In particular, the effect of magnetic anisotropies on the compensation phenomenon, acting on A-atoms and B-ones for the mixed-spin model, has been considered in a zero field. The free energy of a mixed-spin Ising ferrimagnetic system from MFA of the Hamiltonian is calculated. By minimizing the free energy, we obtain the equilibrium magnetizations and the compensation points. The phase diagram of the system in the anisotropy dependence of transition temperature has been discussed as well. Our results of this model predict the existence of many (two or three) compensation points in the ordered system on a simple cubic lattice. 1. Introduction Recently, there has been great interest in stable crystalline room-temperature magnets with spontaneous moments because of their potential device application in thermomagnetic recording, electronic and computer technologies. Besides that, ferrimagnetic ordering plays a crucial role in several novel materials based on molecular compounds [1, 2]. Thus, the study of the Ising model with mixed spins of different magnitudes has attracted considerable attention. Important advance has been directed to the two-sublattice mixed-spin systems with single-ion anisotropies. These systems have been investigated by a variety of techniques, such as exact, mean-field approximation, and effective field theory [3¨C6]. For example, the authors [3] have investigated one constituent having spin-1 and the other constituent having spin-3/2. It has been shown that an outstanding result of this system was discovered experimentally in [3]. The purpose of this work is to investigate a more general mixed-spin Ising model consisting of spin-3/2 and spin-5/2. Our theoretical work may be classified into two types. In the first type, the spin compensation temperature of the system ( ) can be obtained by requiring the total magnetization to be equal to zero for various values of anisotropies though the reduced magnetization of the sublattices forming the system is not equal to zero [3, 7¨C10]. The second class of work is the phase transitions which demand the Landau expansion of the free energy in the order parameter [3, 8, 11]. However, we firstly determine the ground-state phase diagram and study sublattice magnetizations of the mixed-spin ferrimagnetic Ising system with various values of the anisotropies on the basis of the mean-field theory. The basic framework of the theory
%U http://www.hindawi.com/journals/isrn.cmp/2013/759450/