伊辛自旋梯的磁化平台和热力学性质研究

Study on the Magnetization Plateau and Thermodynamic Properties in Spin Ladder

利用传递矩阵方法严格求解了混自旋S=1和S=3/2组成的伊辛自旋梯,考察了系统的磁化过程及外磁场下各向异性对系统热力学性质的影响.发现系统最近邻为铁磁性交换作用,链间次近邻为反铁磁性作用时,系统的磁化强度在m=1/4和m=3/4处出现磁化平台现象,与量子模型中的磁化平台可能出现的位置一致.系统的磁比热和磁化率曲线中出现了新颖的双峰现象.

To investigate the magnetization and the effect of anisotropy on thermal properties in external magnetic field, the transfer matrix method is used to calculate exactly the solution to the magnetization in Ising spin ladder with S = 1 and S = 3/2 mixed together. It＇s found that if the closest neighboring interaction is ferromagnetic and the next closest interaction between two spin chains is antiferromagnetic, the plateaus of the magnetization rn = 1/4 and m = 3/4 appear in the system, which are consistent with the positions where the magnetization plateaus are lXxssibly appearing in quantum model. Novel dual-peak is observed on the curves of specific heat and susceptibility.