MnCo0.95Cu0.05Ge合金的磁性及其磁热效应  

Magnetic properties and magnetocaloric effects in MnCo_(0.95)Cu_(0.05)Ge alloy

作　　者：高湉[1,2] 齐宁宁[1] 孙超 吴梅 刘永生[1] 徐燕[1] 周桃[1] GAO Tian;QI Ning-ning;SUN Chao;WU Mei;LIU Yong-sheng;XU Yan;ZHOU Tao(Department of Physics,Shanghai University of Electric Power,Shanghai 200090,China;Shanghai Key Laboratory of High Temperature Superconductors,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海电力学院物理系,上海200090 [2]上海市高温超导重点实验室,上海大学,上海200444

出　　处：《中国有色金属学报》2018年第8期1597-1602,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(11204171); “电气工程”上海市Ⅱ类高原学科资助项目; Project(16ZR1413600)supported by the Shanghai Municipal Natural Science Foundation,China

摘　　要：采用真空电弧炉熔炼法制备MnCo_(0.95)Cu_(0.05)Ge合金,并分别利用X射线衍射和物性测量系统研究了其结构、磁性和磁热效应。室温下的X射线衍射数据表明,样品呈现六角(Ni_2In型)单相结构;随着温度降低,样品发生顺磁-铁磁二级相变,其居里温度T_C约为257 K。T_C以下样品呈现强铁磁性,这主要是由次晶格Mn-Mn原子间的交换作用引起的。在T_C附近,合金样品显示了巨大的磁热效应;当外加磁场变化为2、5和7 T时,最大磁熵变分别达到了4.49、10.19和13.64 J/(kg·K),相对应的制冷量分别为103.27、249.66和347.82 J/kg。The structure,magnetic and magnetocaloric properties of MnCo0.95Cu0.05Ge alloy prepared by arc melting method were studied.X-ray diffraction data at room temperature indicate that the sample exists a single phase of Ni2In-type hexagonal structure.It shows strong ferromagnetic properties below the Curie temperature（TC）about 257 K.With the increase of temperature,a reversible second order phase transition from ferromagnetic to paramagnetic state is observed at TC,accompanied with a large magnetocaloric effect,which is mainly due to the exchange effect of Mn-Mn ordering.The maximum magnetic entropy changes are 4.49,10.19 and 13.64 J/（kg·K）at applied magnetic field of 2,5and 7 T,the corresponding relative cooling power are calculated to be 103.27,249.66 and 347.82 J/kg,respectively.

关 键 词：MnCoGe合金 磁热效应 铁磁性能 磁化曲线 

分 类 号：O469[理学—凝聚态物理]