Ce_2Fe_(16)Al化合物在居里温度附近的磁性和磁熵变

Magnetic properties and magnetic entropy change of Ce_2Fe_(16)Al near Curie temperature

研究了具有菱方Th2 Zn1 7型结构的Ce2 Fe1 6 Al化合物在居里温度TC 附近的磁性和磁熵变 .实验结果表明 ,在居里温度附近样品的磁特性符合二级相变规律 ,样品的居里温度为 2 75 8K .通过磁化强度与磁场和温度关系的测量 ,计算出临界指数 β=0 44± 0 0 1,γ=1 3 0 ± 0 0 1,δ =3 83 ± 0 0 1,临界指数 β ,γ ,δ基本满足标度率方程γ =β(δ- 1) ,但偏离三维Heisenberg模型的理论值 .Ce2 Fe1 6 Al化合物的磁熵变在居里温度处达到峰值 ,2T外磁场下的最大磁熵变为 1 95J

The magnetic properties and magnetic entropy change near Curie temperature T-C have been investigated for the Ce2Fe16Al compound with a rhombohedral Th2Zn17-type structure. The magnetic behaviour is found to obey the second-order phase transition laws near T-C which is 275.8K. The critical indices beta = 0.44 +/- 0.01, gamma = 1.30 +/- 0.01, delta = 3.83 +/- 0.01 are obtained by calculating the field- and temperature-dependences of magnetization. The critical indices satisfy the scaling law gamma = beta(delta - 1), but these values deviate the three-dimensional Heisenberg model. The maximum entropy change at T-C under a field of 2 T is 1.95J/kgK.