Effects of two different random single-ion anisotropies on the critical properties of a mixed spin-2 and spin-5/2 Ising system

• Published in: Physica A Vol. 450; pp. 180 - 192
• Main Authors: da Cruz Filho, J.S., Tunes, T.M., Godoy, M., de Arruda, A.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2016
• Subjects: Anisotropy; Compensation; Displays; Free energy; Inequalities; Ising model; Mean-field approximation; Order parameters; Phase diagram; Phase diagrams; Random single-ion anisotropies; Phase diagram; Mean-field approximation; Random single-ion anisotropies
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2015.12.096

We have studied the effects of two different random single-ion anisotropies in the phase diagram and on the critical properties of a mixed spin-2 and spin-5/2 Ising ferrimagnetic system. We employed the mean-field theory based on the Bogoliubov inequality for the Gibbs free energy. We have used the Landau expansion of the free energy in the order parameter to describe the phase diagram. We have shown that the phase diagram temperature as function of random single-ion anisotropy displays tricritical behavior. We also investigated the existence and dependence of a compensation temperature on random single-ion anisotropies. The critical and compensation temperatures increase with increasing of the random single-ion anisotropies values. •Several phase diagrams are obtained for the mixed spin-2 and spin-5/2 Ising system under the effects of random single-ion anisotropies.•The mean-field theory based on the Bogoliubov inequality for the Gibbs free energy is examined for the system.•The Landau expansion of the free energy in the order parameter is obtained to describe the phase diagrams.•The tricritical behavior is examined.