Er_2Fe_(17-x)Si_x合金的分子场理论分析

Molecular Field Theory Analysis of Er_2Fe_(17-x)Si_x Alloys

用两格点分子场理论分析了合金Ｅｒ２Ｆｅ１７－ｘＳｉｘ（ｘ＝０，１，２）的饱和磁化强度随温度的变化关系，得到了分子场系数ｎＥＥ、ｎＥＦ、ｎＦＦ，计算了居里温度，给出了分子场强肽ＨＥｒ（Ｔ）、ＨＦｅ（Ｔ）随温度变化的曲线．结果表明，当ｘ增加时，分子场系数 ｎＦＦ明显增大，分子场强度 ＨＦＥ（Ｔ）亦随之增大，而 ＨＥｒ（Ｔ）在较低温区减小，在较高温区增大，并且ｎＦＦ的增大是居里温度提高的主要原因．

Through the two-sublattice molecular field theory, the temperature dependence of the saturation magnetization of Er2Fe17-xSix alloys has been analysed. The molecular field coefficients nEE, nEF and nFF are obtained and Curie temperatures of the alloys are calculated. And also the curves of the intensity of molecular field HEr (T)and HFe (T)are plotted. The results of analysis have showed that with the increment of x, the molecular field coefficient nFF increase obviously and the increment of HFe(T) follows as well with the decrease of HEr(T) in the range of low temperature and the increase in the range of higher temperature. The increse of nFF is the main cause of the rising of Curie tempera- ture.