Ho(Co_(1-x)Mn_(x))_(2)合金的相变类型调控和磁热效应优化  

Tuning phase transitions and optimization of the magnetocaloric effect in Ho(Co_(1-x)Mn_(x))_(2) alloys

作　　者：徐成成 王立昇 汪浩波 韩志达 XU ChengCheng;WANG LiSheng;WANG HaoBo;HAN ZhiDa(School of Physics and Electronic Engineering,Changshu Institute of Technology,Changshu 215500,China;School of Materials Science and Engineering,China University of Mining and Technology,Xuzhou 221116,China;Jiangsu Laboratory of Advanced Functional Materials,Changshu Institute of Technology,Changshu 215500,China)

机构地区：[1]常熟理工学院电子信息工程学院,常熟215500 [2]中国矿业大学材料科学与工程学院,徐州221116 [3]常熟理工学院江苏省新型功能材料重点建设实验室,常熟215500

出　　处：《中国科学：物理学、力学、天文学》2021年第6期154-160,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:51371004)资助项目。

摘　　要：在磁制冷材料中,由于一级相变和二级相变材料各有其优缺点,将相变调节到一级/二级相变的临界点有望使材料兼具两种材料的优点.我们通过在一级相变HoCo_(2)合金中加入少量Mn,使一级相变逐渐转变为二级相变,并研究了相变类型转变过程中的磁熵变、磁滞的变化.结果表明,当x=0.02时,材料接近一级相变和二级相变的临界点,具有大的磁热效应和很小的磁滞损耗.当x>0.02时,样品的磁相变变为二级相变,磁热效应大大降低.该研究表明,在RCo_(2)基磁制冷材料中,调节相变类型是优化磁热性能的有效方法.In magnetic refrigerants, tuning the materials to the first-order/second-order borderline is expected to equip the material with the advantages of the first-and second-order transitions. In this work, we performed a systematic study on the nature of the phase transition, the magnetic entropy change, and the hysteresis loss in the Mn-doped Ho(Co_(1–x)Mn_(x))_(2) alloys. We found that at x = 0.02, the material was close to the borderline of the first-order/second-order transition and exhibited a large magnetocaloric effect along with a small hysteresis loss. At x>0.02, the phase transition in the sample became a second-order type, and the magnetocaloric effect was greatly reduced. These results indicate that tuning the nature of phase transition in the RCo2-based magnetic material is an effective strategy of optimizing its magnetocaloric performance.

关 键 词：Laves合金 一级相变 二级相变 磁热效应 

分 类 号：O469[理学—凝聚态物理] TB64[理学—电子物理学] TG132.27[理学—物理]