The van Hemmen model and effect of random crystalline anisotropy field

• Published in: Journal of magnetism and magnetic materials Vol. 398; pp. 253 - 258
• Main Authors: de Morais, Denes M., Godoy, Mauricio, de Arruda, Alberto S., da Silva, Jonathas N., Ricardo de Sousa, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2016
• Subjects: Anisotropy; Crystal structure; Equations of state; Free energy; Magnetism; Mathematical models; Phase diagram; Phase diagrams; Phase transformations; Random crystalline field; Van Hemmen model; Van Hemmen model; Phase diagram; Random crystalline field
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2015.09.050

In this work, we have presented the generalized phase diagrams of the van Hemmen model for spin S=1 in the presence of an anisotropic term of random crystalline field. In order to study the critical behavior of the phase transitions, we employed a mean-field Curie–Weiss approach, which allows calculation of the free energy and the equations of state of the model. The phase diagrams obtained here displayed tricritical behavior, with second-order phase transition lines separated from the first-order phase transition lines by a tricritical point.
•Several phase diagrams are obtained for the model.•The influence of the random crystalline anisotropy field on the model is investigated.•Three ordered (spin-glass, ferromagnetic and mixed) phases are found.•The tricritical behavior is examined.