Giant magnetocaloric effect in Gd5(Si2Ge2) alloy with low purity Gd
Giant magnetocaloric effect in Gd5(Si2Ge2) alloy with low purity Gd
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DOI：
10.1590/s1516-14392004000400005
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发表时间：
2004-12
影响因子：
1.7
通讯作者：
Cleber S. Alves;S. Gama;A. A. Coelho-A.;E. Plaza;A. M. Carvalho;L. P. Cardoso;A. Persiano
中科院分区：
文献类型：
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作者：
Cleber S. Alves;S. Gama;A. A. Coelho-A.;E. Plaza;A. M. Carvalho;L. P. Cardoso;A. Persiano
Gd_5（Ge_（1-x）Six），x < 4基合金是~20 - ~290 K范围内磁制冷的潜在候选材料。然而，大规模使用该技术的最大障碍之一是利用高纯Gd金属（99.99wt.（%））来制备GdGeSi合金，因为杂质元素降低了磁热效应（EMC）1的强度。在这项工作中，我们证明了退火的Gd 5Ge 2Si 2可以促进显着的EMC值相比，获得的合金与高纯Gd。此外，铸态合金和退火合金不是双相的，但在其微观结构中具有至少两个结晶相。X射线分析，光学和电子显微镜和磁化测量的结果报告。
Gd5(Ge1-xSix), x < 4 based alloys are potential candidates for magnetic refrigeration in the range ~20 - ~290 K. However, one of the greatest obstacles for the use of that technology in large scale is the utilization of high pure Gd metal (99.99 wt. (%)) to produce the GdGeSi alloys, since the impurity elements decrease the intensity of the magnetocaloric effect (EMC)1. In this work, we prove that annealing of the Gd5Ge2Si2 can promote remarkable values for the EMC in comparison to those obtained for the alloy with high pure Gd. Also, the as cast alloy and the annealed alloy are not monophasic, but have at least two crystalline phases in their microstructure. Results for X-ray analysis, optical and electronic microscopy and magnetization measurements are reported.