二模磁场中随机晶场作用混合自旋横向Ising模型的临界行为  

The Critical Behaviors of Mixed Spin Transverse Ising Model with the Random Crystal Field in a Bimodal Magnetic Field

作　　者：丁直[1] 晏世雷[1] 

机构地区：[1]苏州大学物理科学与技术学院,江苏苏州215006

出　　处：《常熟理工学院学报》2013年第4期29-34,共6页Journal of Changshu Institute of Technology

基　　金：江苏省高校优势学科建设工程资助项目(YK40000112)

摘　　要：在有效场理论和切断近似的框架内,研究了二模磁场中随机晶场作用的混合自旋横向Ising模型的临界行为.在T-h相图中,晶场浓度对有序相的影响需要将二模磁场分段考虑;大的晶场和适当的晶场浓度有利于二级重入相变现象;但横场对三临界点的作用值得更多研究.在T-D相图中,负晶场比例较大降低有序相,正晶场比例较大增大有序相;强二模磁场和横场都抑制有序相,但强二模磁场有利于三临界点的出现,而横场抑制三临界点.在T-Ω相图中,晶场和晶场浓度对有序相范围有显著影响.Within the framework of the effective field theory （EFT） and cutting approximation, the critical behaviors of mixed spin transverse Ising model with the random crystal field in a bimodal magnetic field are investigated. In T-h space, the effect from crystal field concentration to ordered phase range needs to be considered at different areas of bimodal magnetic field. A big crystal field and appropriate random concentration benefit the second phase reentrance phenomenon. The result shows it needs more discussion about the influence of trans- verse field to the tricritical point. In T-D space, a high proportion of negative crystal field leads to small or- dered phase range while high proportion of positive crystal field brings large ordered phase range. Both a big bi- modal magnetic field and transverse field can depress ordered phase. But a big bimodal magnetic field can in- crease tricritical point temperature while the transverse field suppresses tricritical point. In T-D space, crystal field and crystal field concentration have a marked impact on ordered phase.

关 键 词：混合自旋横向Ising模型 临界行为 随机晶场 二模磁场 

分 类 号：O469[理学—凝聚态物理]