磁性粒子Fe(Mn)对FeMnAl合金磁性和热力学性质的贡献  

Contributions of iron and manganese to the global magnetic and thermodynamic properties of disordered FeMnAl alloys

作　　者：高清河[1,2] 杜安[2] 刘锦超[3] 

机构地区：[1]辽宁中医药大学信息工程学院,沈阳110847 [2]东北大学理学院,沈阳110004 [3]四川大学原子与分子物理研究所,成都610065

出　　处：《四川大学学报（自然科学版）》2015年第4期845-849,共5页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金(11104247;11364007)

摘　　要：基于伊辛模型的单自旋反转蒙特卡洛算法,研究了无序Fe0.5Mn0.1Al0.4合金中的铁磁性粒子Fe和反铁磁性粒子Mn对体系的磁性和热力学性质的贡献.首先,检验了晶格大小以及Monte Carlo模拟步数对结果的影响,证实了低温合金阻挫的存在,确定了Fe0.5Mn0.1Al0.4合金的冻结温度以及居里温度;其次,详细研究了铁磁性粒子Fe和反铁磁性粒子Mn对Fe0.5Mn0.1Al0.4合金的磁化强度和磁化率的贡献,发现低温区域磁化强度和磁化率的变化是由反铁磁性粒子Mn决定的,而在高温区域的变化是由铁磁性粒子Fe决定的.最后,通过与Fe0.5Al0.5合金以及Fe0.6-xMnxAl0.4(x=0.05、0.1、0.2、0.3)合金的磁性和热力学性质的比较,发现高温区域磁性粒子Mn可以被看成是Al原子,但正是Mn粒子才使得Fe0.5Mn0.1Al0.4合金在低温区域存在着自旋玻璃态.By means of single spin flip Metropolis dynamics on the basis of a random site-diluted three- dimensionalIsing model with nearest-neighbor interactions, contributions of ferromagnetic particles Fe and antiferromagnetic particles Mn to magnetic properties and thermodynamic properties of the disorder- ed system are researched. Firstly, the effect of the lattice size and Monte Carlo simulation steps on the thermodynamic quantities is checked, the existence of frustration in the low temperature and transition temperature （freezing temperature and Curie temperature ） are confirmed. Secondly, contributions of ferromagnetic particles Fe and antiferromagnetic particles Mn to the magnetization （magnetic suscepti- bility） of the disordered system are researched, suggesting that the antiferromagnetic Mn particle plays a crucial role in determining low-temperature magnetization （magnetic susceptibility）, whereas the high -temperature magnetization （magnetic susceptibility） is contributed mainly by Fe component. In orderto emphasize the role of manganese particles in FeMnA1 system, the thermodynamic properties of theFe0.6-xMnxAl0.4 alloy series, bccFe0.5Al0.5 alloys and Fe0.5Mn0.1Al0.4 alloys are simulated and com- pared on the basis of a Metropolis dynamics. Through the above simulations, we reveal that the antifer- romagnetic Mn particle in the high temperature area can be regarded as nonmagnetic Al particle, but plays a crucial role in determining low-temperature phase transition. In contrast to Mn particle, the high-temperature magnetic properties and thermodynamic properties are determined by Fe contribu- tion.

关 键 词：伊辛模型 蒙特卡洛模拟 磁化强度 磁化率 

分 类 号：O482.5[理学—固体物理]