摘要
使用了约80%的廉价铁原料,制备了LaFe11.6Si1.4C0.5间隙化合物。研究表明:该间隙化合物仍保持了LaFe11.6Si1.4的NaZn13立方晶体结构,间隙C原子的引入导致晶格膨胀了约0.35%,居里点提高了约50K;同时,仍然保持大的磁熵变,在0～2T磁场变化下,磁熵变达到Gd的2倍以上,大磁熵变源于磁场诱发的巡游电子变磁相变。该间隙化合物具有大磁熵变。
LaFe 11.6 Si 1.4 C 0.5 interstitial compound was prepared by s olid-solid phase reaction. X-ray diffraction patterns reveal that the lattice constant increases by 0.35% due to the introduction of the interstitial C atoms, while the cubic NaZn 13 -type structure remains unchanged. The Curie temper ature increases from 192 to 243 K due to the obvious lattice expansion. The maxi mal magnetic entropy change |Δ S | keeps very large after carbonization, a nd is about twice as that of Gd under a magnetic field change of 0～2 T, which i s attributed to the field-induced itinerant-electron metamagnetic transition. The large |Δ S | and low cost due to about 80wt% Fe material is used make L aFe 11.4 Si 1.6 C 0.5 promising candidate for magnetic refrigerants in corresponding temperature range.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2003年第4期478-480,共3页
Journal of the Chinese Society of Rare Earths
基金
863项目(2002AA324010)
973项目(G1998061305)
国家自然科学基金项目(59525101)
中科院王宽诚博士后基金资助
关键词
凝聚态物理
NaZn13型间隙碳化物
磁熵变
磁致冷材料
稀土
condensed state physics
NaZn 13 -type inters titial carbides
magnetic entropy change
magnetic refrigerant
rare earths
