摘要
近年来,磁性纳米管的物理性质和相关应用得到了人们的广泛关注.利用有效场理论研究了纳米管上双模随机晶场中Blume-Capel模型的磁化强度和相变性质,得到了系统的磁化强度与温度和随机晶场的关系及其相图.结果表明:系统在稀释晶场、交错晶场和同向晶场中会表现出不同的磁学性质和相变行为;稀释晶场和交错晶场会抑制系统的磁化强度,导致其基态饱和值小于1,而同向晶场则不会;随着随机晶场参量的变化,系统存在多个相变温度,并呈现出三临界现象和重入现象.
Recently, the physical properties and applications of the magnetic nanotube have attracted a great deal of theoretical and experimental attention. The magnetization and phase transition of spin-1 Blume-Capel model on a cylindrical Ising nanotube with bimodal random crystal fields are investigated by using the effective field theory. Employing numerical calculations, we obtain the phase diagrams and the magnetization, which depend on the temperature and the parameters of random crystal fields. Our obtained results are as follows.（i） Changing the probability（p） and the ratio of the crystal fields（α）, the bimodal random crystal fields may describe different doped atoms acting on spins. Especially, for p = 0.5,choosing α = 0,-1.0,-0.5 and 0.5, the bimodal random crystal fields can respectively degrade four typical distributions of random crystal fields, i. e., the distribution of diluted crystal fields, the distribution of symmetry staggered crystal fields, the distribution of non-symmetry staggered crystal fields, and the distribution of same-direction crystal field.（ii）The system exhibits different magnetic properties and phase transition behaviors in the diluted, staggered and samedirection crystal field. The diluted and staggered crystal fields may reduce the magnetization of the system, resulting in the ground state saturation value of magnetization, which is less than 1, while the same-direction crystal fields cannot result in a similar behavior.（iii） The system shows several phase transition temperatures, i.e., first-order and secondorder phase transitions and reentrant phenomenon as the parameters of bimodal random crystal fields change. The tricritical point and reentrant phenomenon do exist for certain values of the probability, the negative crystal field and the ratio of the crystal fields in the system. The relevant experiment is needed to verify the above-mentioned theoretical results.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第24期326-333,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11275112
11302118)
教育部博士点专项科研基金(批准号:20123705110004)
山东省自然科学基金(批准号:ZR2011AM018
ZR2013AQ015)资助的课题~~
