摘要
在氩气气氛中用熔炼法制备了Er2-xCexFe17(x=0,0.05,0.08,0.1,0.15,0.2,0.3,0.4)化合物,通过粉末X射线衍射和SQUID磁强计研究了样品的结构、磁性和磁熵变。结果表明,Er2-xCexFe17化合物具有Th2Ni17型六方结构,通过成分微调使其居里温度处在室温附近。Er2-xCexFe17化合物的λ形(-△SM)-T曲线表明其在居里点附近发生的相变属于二级相变,它使化合物可在较宽温区范围内保持较大的磁熵变。当x=0.05-0.15时,Er2-xCexFe17化合物在2.0和5.0 T外场作用下的最大磁熵变达到金属Gd的40-50%,且其化学性质稳定、制冷温区宽、价格低廉,是一类性价比较高、应用潜力较大的新型低场室温磁制冷工质材料。
A series of Er2-xCexFe17 (x =0,0.05,0.08,0.1,0.15,0.2,0.3,0.4) compounds were prepared by arc melting under purified argon atmosphere. Structure, magnetic properties and magnetic entropy changes of Er2-xCexFe17 compounds were investigated by means of X-ray diffraction pattern and SQUID magnetometer. The results show that the crystal structure is Th2Ni17-type hexagonal for Er2-xCexFe17 compounds, and the Curie temperature of Er2-xCexFe17 compounds can be shifted to room temperature around by a small adjustment of composition. The typical λ-shape ( - △SM)-T curves of Er2-xCexFe17 compounds indicate that the phase transition near Curie temperature belongs to a second order one which conduces the compounds with larger magnetic entropy changes in a comparatively wide range of temperature. With the Ce content x between 0.05 and 0.15, the Er2-xCexFe17 compounds have a higher magnetic entropy changes and the maximal values are about 40 - 50% of the highest magnetic entropy changes of pure metal Gd in external field of 2 or 5 T. Er2-xCexFe17 compounds are potential working media for magnetic refrigeration due to their stable chemical properties, wide temperature range for magnetic refrigeration and low cost.
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2006年第4期489-492,497,共5页
Journal of Materials Science and Engineering
基金
广东省自然科学基金资助项目(05300306)
广东省自然科学基金重点资助项目(C013003)
广东省稀土办攻关资助项目(102-B25770)
广东省高教厅重点资助项目(102-B24480)
中国教育部骨干教师计划资助项目(305-D40130)
华南理工大学自然科学基金资助项目(305-E5040360)
华南理工大学"学生研究计划"资助项目(B01-Y13017)
关键词
Er2-xCexFe17金属间化合物
磁熵变
磁制冷
二级相变
Er2-xCexFe17 intermetallic compounds
magnetic entropy change
magnetic refrigeration
second order phase transition