A phenomenological fitting curve for the magnetocaloric effect of materials with a second-order phase transition
A phenomenological fitting curve for the magnetocaloric effect of materials with a second-order phase transition
复制标题
二阶相变材料磁热效应的唯象拟合曲线
DOI：
10.1063/1.2913166
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发表时间：
2008-06-01
影响因子：
3.2
通讯作者：
Franco, V.
中科院分区：
文献类型：
--
作者：
Dong, Q. Y.;Zhang, H. W.;Franco, V.
本文研究了具有二级相变的Gd、La（Fe_（0.92）Co_（0.08））_（11.83）Al_（1.17）、LaFe_（10.8）Si_（2.2）、Mn_5Ge_（2.7）Ga_（0.3）、Nd_2AlFe_（13）Mn_3和TbCo_2多晶样品的磁熵变。一个统一的唯象函数，描述了这些材料的磁熵变。这对磁制冷机的设计具有重要的指导意义。研究了最大熵变随场变化的临界指数的场依赖性。平均场理论所预言的临界指数值2/3仅在中等场值时才能满足。制冷剂容量进行了分析和比较的拟合函数的预测。
The magnetic entropy change of polycrystalline samples Gd, La(Fe0.92Co0.08)11.83Al1.17, LaFe10.8Si2.2, Mn5Ge2.7Ga0.3, Nd2AlFe13Mn3, and TbCo2 with a second-order phase transition has been investigated. A uniform phenomenological function that describes the magnetic entropy change is found for these materials. This could be of great benefit for the design of magnetic refrigerators. The field dependence of the critical exponent for the variation in the maximum entropy change with field is studied. The critical exponent value of 2/3, which is predicted by the mean field theory, is only satisfied for moderate field values. The refrigerant capacity is analyzed and compared to the predictions of the fitting function.