具有Fe_4N结构的混自旋最近邻的Ising模型磁性质  

Magnetic Properties of Mixed Spin Ising Model in Nearest Neighbor Interaction With Fe4N Structure

作　　者：许星光[1] 赵杰[1] 

机构地区：[1]辽宁石油化工大学理学院,辽宁抚顺113001

出　　处：《辽宁石油化工大学学报》2009年第3期81-84,共4页Journal of Liaoning Petrochemical University

基　　金：教育部博士点基金项目(20040145019)

摘　　要：在晶场作用下对具有Fe4N结构的混自旋Ising模型,采用平均场理论,推导出考虑最近邻相互作用下系统的磁矩和自由能的理论公式,重点考察了最近邻格点的相互作用及晶场对系统磁性质的影响,得到了系统的基态相图和有限温度的磁化曲线,观察到系统的相变特征:重入现象及二级相变。研究发现,二级相变是普遍现象,当DA/|J1|、DB/|J1|取得足够大时,系统一定存在二级相变。基态相图中D1与O1及D2与O1、O2的边界线上会发生重入现象。When the crystal field exists, the mixed spin Ising model in nearest neighbor interaction with Fe4N structure was studied within the mean field theory. The theoretic expressions of magnetization and free energy in the nearest neighbor interaction system were deduced. The influences of the nearest interactions and the crystal field on the magnetic properties were mainly explored. The ground-state phase diagram and magnetization curves in finite temperature were obtained. Abundant phase transition characters were observed in the system： reentrantant phenomena, and second-order phase transitions. It is found that second- order phase transitions are general phenomena, and second-order phase transitions must exist in the system when DA/｜J1｜ and DB/｜J1｜ get the adequate large values. On the boundary lines of D1 to O1and D2 to O1,O2 reentrantant phenomena may occur.

关 键 词：平均场理论 混自旋 基态相图 磁化曲线 重入现象 

分 类 号：O414.13[理学—理论物理]