Dynamic phase transition in the kinetic spin-5/2 Blume–Emery–Griffiths model in an oscillating external magnetic field

Abstract

Employing a mean-field approach, we study the stationary states of the kinetic spin-5/2 Blume–Emery–Griffiths (BEG) model under the presence of a time-varying (sinusoidal) magnetic field by using the Glauber-type stochastic dynamics. We employ the Glauber transition rates to construct the set of dynamic mean-field equations. We investigate the time variation in average order parameters to find the phases in the system, and the thermal behavior of the dynamic order parameters to characterize the nature (continuous or discontinuous) of the dynamic phase transtions and to the dynamic phase transition temperature. The dynamic phase diagrams are presented in three different planes. The phase diagrams contain the ferromagnetic-5/2, the ferromagnetic-3/2, the ferromagnetic-1/2, the ferroquadrupolar, and disordered fundamental phases. They also include the nine coexisting or mixed phases composed of binary and ternary combinations of fundamental phases that strongly depend on the interaction parameters. The phase diagrams display the critical end point, double critical end point, triple point, quadruple point, and one, two, or three special points and the dynamic tricritical point that depends on the interaction parameters.

Keywords:

• spin-5/2 Blume–Emery–Griffiths model
• oscillating magnetic field
• Glauber-type stochastic dynamics
• dynamic phase transition
• dynamic phase diagram

PACS::

• 05.50.+q
• 05.70.Fh
• 64.60.Ht
• 75.10.Hk

Acknowledgements

This work was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK), grant no. 107T533, and Erciyes University Research Funds, grant no. FBA-06-01.