低磁场下LaFe10.7Co0.9Si1.4合金磁相变行为的标度理论临界参数研究
Critical Parameters of Scaling Theory for Magnetic Phase Transformation Behavior of LaFe10.7Co0.9Si1.4 Alloy under Low Magnetic Field
陈湘 1王晓燏 1何金彦 1黄鑫 1杨若蛟1
作者信息
- 1. 内江师范学院物理与电子信息工程学院,四川 内江 641112
- 折叠
摘要
基于X射线粉末衍射谱,以及等温与等场情况下磁化强度分别随温度与磁场变化的数据,系统地研究了 LaFe10.7Co0.9Si1.4合金的磁性以及磁相变类型.M-T曲线中的近似零热滞、居里温度附近Arrott图的直线性、磁熵变随温度变化图的对称状等,均表明LaFe10.7Co0.9Si1.4合金的磁相变为二级相变.基于 Arrott图,并结合Arrott-Noakes状态方程和Kouvel-Fisher方程,拟合的相变临界参数分别为β=0.4746 与γ=0.9812,β=0.4727和γ=1.0482,二者具有高度的自洽性.另外,根据居里温度附近的等温磁化曲线方法确定了临界指数δ的值,大小为3.1587.这些参数值表明LaFe10.7Co0.9Si1.4合金在相变过程局域磁矩之间的相互作用是长程关联相互作用,属于铁磁-顺磁连续二级相变.另外,通过对不同磁场下合金的磁熵变进行了归一化处理,并结合伦兹函数对归一化曲线进行了拟合,得到了相关拟合系数.
Abstract
Based on X-ray powder diffraction spectrum,isothermal magnetization and equifield temperature change data,the magnetic properties and magnetic phase transition types of LaFe10.7Co0.9Si1.4 alloy were systemati-cally studied in this paper.The approximate zero thermal hysteresis in the M-T curve,the linearity of the arrott diagram near the Curie temperature,and the symmetry of the magnetic entropy change with temperature diagram all show that the magnetic phase transition of LaFe10.7Co0.9Si1.4 alloy is a second-order phase transition.Based on Arrott diagram,combined with Arrott-Noakes state equation and Kouvel Fisher equation,the fitted critical pa-rameters of phase transition are β=0.4746 and γ=0.9812,β=0.4727 andγ=1.0482,the two results have a high degree of self consistency.In addition,the critical index is determined to be 3.1587 by the critical isothermal curve method.These parameter values show that the magnetic interaction of LaFe10.7Co0.9Si1.4 alloy can be de-scribed by the molecular mean field model based on long-range interaction,that is,the critical interaction of second-order magnetic transformation.In addition,the magnetic entropy change of LaFe10.7Co0.9Si1.4 alloy under dif-ferent magnetic fields was normalized,and the normalized curve was fitted using the Lorentz function to obtain the relevant fitting coefficients.
关键词
LaFe10.7Co0.9Si1.4合金/磁相变/标度理论/分子平均场模型Key words
LaFe10.7Co0.9Si1.4 alloy/magnetic phase transition/scaling theory/molecular mean-field model引用本文复制引用
基金项目
四川省科技厅资助项目(2022YFG0267)
国家级大学生创新创业训练计划资助项目(X2022011)
出版年
2024
NETL
NSTL
万方数据