Thermodynamic properties of a multiferroic antiferromagnetic spin system: The influence of Dzyaloshinskii Moriya interaction

Abstract

In this paper, we address the influence of Dzyaloshinskii Moriya (DM) interaction on the thermodynamic properties of a multiferroic antiferromagnetic spin system using the spin wave theory (SWT) as a diagonalization method which, associated to the statistical physics, helps to evaluate the statistical sum. The basic factors in thermodynamics, such as the Boltzmann entropy and the specific heat capacity at thermal equilibrium, are obtained. Analyzing the numerical results, it follows that the DM interaction is the best candidate that can help to maintain in long time the system in its coherent state. Furthermore, we find that the influence of the DM interaction is more accentuated at low-temperature and that it enables the system to release heat energy. On the other hand, the fact that the specific heat capacity tends to the constant clearly shows that the system obeys the Dulong–Petit law. In addition, our results also show that for high magnetic field (greater than B[Formula: see text]=[Formula: see text]30 Tesla), the magnetic field dependence of both entropy and specific heat shows a peak-like behavior and that the DM interaction raises the corresponding critical magnetic field but lowers the peak amplitude. It follows that the spin-flop transition occurs in the system and that the strong magnetic field withdraw the antiferromagnetic phase. Overall, we find that the DM interaction is a promising candidate for the control of our system.