各向异性亚铁磁链的自旋波理论  

Spin-Wave Theory of an Anisotropic Ferrimagnetic Spin Chain

作　　者：彭亮[1] 陈斌[1,2] 

机构地区：[1]上海理工大学理学院,上海200093 [2]杭州师范大学理学院,杭州310018

出　　处：《上海理工大学学报》2015年第4期307-310,316,共5页Journal of University of Shanghai For Science and Technology

摘　　要：利用自旋波理论,对各向异性的亚铁磁链进行研究,得到了低激发能谱,同时计算了该体系的自由能、比热容等热力学量.进一步考虑在外磁场作用下该系统的情况,计算了系统的磁化强度,其磁化强度曲线出现一个平台,此平台随着各向异性因子的增加而逐渐消失.通过对这些物理量的研究,得出各向异性因子在亚铁磁链中起到很重要的作用.对于该体系中准粒子的激发,在两个临界值之间的各向异性因子对其起到一定的抑制作用,而在其它的情况下,这种作用会消失.因此,对于各向异性的亚铁磁链,各向异性因子就像是该系统的开关.By using the spin-wave theory,an anisotropic ferrimagnetic spin chain was studied and its low-lying excitation energy spectrum was obtained.The thermodynamic quantities of the system,such as the free energy,specific heat etc.were calculated.The state of the system in an external magnetic field was considered and the strength of magnetization was investigated.In the presence of external magnetic field,there exists a magnetization plateau of the anisotropic ferrimagnetic spin chain.The plateau disappears with the increase of the anisotropic factor.By studying the physical properties of the system,it concludes that the anisotropic factor plays an important role in the anisotropic ferrimagnetic spin chain.It can restrain the quasi-particle excitation in the system when the value of the anisotropic factor is within two critical points.In other cases,this action will disappear.So,for the ferrimagnetic spin chain,the anisotropic factor plays like a switch.

关 键 词：自旋波理论 各向异性 亚铁磁链 

分 类 号：O482[理学—固体物理]