材料期刊网

The ground-state phase diagrams and the magnetization curves of the spin-3/2 transverse Ising model with longitudinal crystal field D are studied within the framework of mean-field theory (MFT) and effective-field theory (EFT), respectively. A simple calculation method of the internal energy is presented within the framework of EFT. In the ground-state phase diagram given by using EFT, the second-order phase transition line is divided into two segments by the first-order phase transition line: one starts from a critical end point and extends to D -> -infinity; the other one starts from a tricritical point and extends to D -> +infinity, while it does not occur in MFT. Some interesting phenomena of the first-order phase transition from one ordered phase to another one ordered have been found. (c) 2007 Elsevier B.V. All rights reserved.