Optimization of La(Fe,Co)13−xSix based compounds for magnetic refrigeration
Optimization of La(Fe,Co)13−xSix based compounds for magnetic refrigeration
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DOI：
10.1088/0953-8984/19/23/236230
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发表时间：
2007-05
期刊：
影响因子：
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通讯作者：
M. Balli;D. Fruchart;D. Gignoux
中科院分区：
文献类型：
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作者：
M. Balli;D. Fruchart;D. Gignoux
通过X射线衍射和磁测量研究了Co对LaFe11.7−xCoxSi1.3(x=0，0.3，0.4，0.5，0.6)和LaFe11.2−xCo0.7+xSi1.1(x=0，0.1，0.2)化合物的磁性、结构和磁热性能的影响。对于LaFe11.7−xCoxSi1.3系列，居里温度Tc随Co含量的增加而增大。当x增加到0.6时，LaFe11.7−xCoxSi1.3合金的相变温度从190K增加到265K，5 T下等温熵变−Δ的峰值从28 J kg−1 K−1下降到15 J kg−1 K−1。同时，随着LaFe11.2−xCo0.7+xSi1.1配方中Co含量从0增加到0.2，5 T下的TC从270 K过渡到294 K，−ΔSmax从16.5 J kg−1 K−1下降到13.5 J kg Ericsson循环。因此，我们选择了一些以LaFe11.7−xCoxSi1.3(x=0.4，0.5，0.6)和LaFe11.2−xCo0.7+xSi1.1(x=0.1和0.2)化合物为基础的合金，以形成工作在240-300K温度范围内的复合材料。计算了各组分的最佳质量比与磁场的关系。在240-300K的温度范围内，复合材料的熵变基本保持不变。
The effect of Co on the magnetic, structural and magnetocaloric properties of the LaFe11.7−xCoxSi1.3 (x = 0, 0.3, 0.4, 0.5, 0.6) and LaFe11.2−xCo0.7+xSi1.1 (x = 0, 0.1, 0.2) compounds was investigated by x-ray diffraction and magnetic measurements. For LaFe11.7−xCoxSi1.3 series, the Curie temperature TC increases with increasing Co content. By varying x up to 0.6, the TC of LaFe11.7−xCoxSi1.3 alloys increases from 190 to 265 K and the peak of the isothermal entropy change −ΔSmax decreases from 28 to 15 J kg−1 K−1 under 5 T. Meanwhile, with Co concentration increasing from 0 to 0.2 in LaFe11.2−xCo0.7+xSi1.1 formula, TC passes from 270 to 294 K and −ΔSmax decreases from 16.5 to 13.5 J kg−1 K−1 under 5 T. Besides, for magnetic refrigeration systems using the Ericsson cycle, the entropy change must remain constant over the refrigeration range. So, we selected some alloys based on LaFe11.7−xCoxSi1.3 (x = 0.4, 0.5, 0.6) and LaFe11.2−xCo0.7+xSi1.1 (x = 0.1 and 0.2) compounds in order to form a composite material working in the 240–300 K temperature range. The optimal mass ratios of the constituents versus magnetic field were calculated. The obtained entropy change of the composite remains approximately constant within the temperature range 240–300 K.