Magnetic properties of Ising metamagnet in both external longitudinal and transverse fields

作者：Geng Jiajia; Wei Guozhu^*

来源：Journal of Magnetism and Magnetic Materials, 2009, 321(13): 1964-1970.

DOI：10.1016/j.jmmm.2008.12.020

• Transverse field
• Ising metamagnet
• Effective-field theory
• Gibbs free energy
• First-order phase transition

The phase diagrams of a two-sublattice Ising metamagnet at finite temperature in a mixed longitudinal field and a transverse magnetic field are investigated by the use of an effective-field theory (EFT) with correlations. In addition to the second-order transition lines, the first-order transition lines are also presented in the phase diagrams, since the Gibbs free energy can be calculated numerically. The results show that there is no fourth-order critical line in the phase diagrams given by using EFT as found by using mean-field theory (MFT). The tricritical lines and their projection in the t-h(x) plane obtained by using EFT are also quite different from those by using MFT. Only one type of phase diagram is obtained by using EFT while three kinds of phase diagrams are obtained by using MFT, which indicates that only the first kind of phase diagrams obtained by using MFT is reliable. Furthermore, it is shown that the region of first-order transitions increases as the transverse magnetic field h(x) decreases.

• 出版日期2009-7
• 单位东北大学