Ho_(3)NiSi_(2)合金相关系和相结构及磁性研究  

Studies of phase,structure and magnetic property in Ho_(3)NiSi_(2) alloy

作　　者：陈湘[1,2] 王静 王晓燏 刘莉 肖洋 谭文兵 CHEN Xiang;WANG Jing;WANG Xiao-yu;LIU Li;XIAO Yang;TANWen-bin(College of Physics and Electronic Information Engineering,Neijiang Normal University,Neijiang 641100,China;Ames Laboratory,U.S.Department of Energy,Iowa State University,Ames,Iowa 50011-2416,USA)

机构地区：[1]内江师范学院物理与电子信息工程学院,内江641112 [2]Ames Laboratory,U.S.Department ofEnergy,Iowa StateUniversity,Ames,Iowa 50011-3020,USA

出　　处：《中国有色金属学报》2022年第5期1383-1390,共8页The Chinese Journal of Nonferrous Metals

基　　金：四川省科技厅资助项目(2017JY0182)。

摘　　要：本文在分析XRD谱、等温磁化曲线和等磁场变温磁化曲线的基础上,主要研究Ho_(3)NiSi_(2)合金的相结构、磁性相变和磁热性能。结果表明:采用不同方法制备的Ho_(3)NiSi_(2)合金中,第二相Ho_(5)Si_(3)含量存在明显差异,主相的原子占位也存在一定的差异。在低磁场下,Ho_(3)NiSi_(2)合金存在两个磁相变,一个是T_(SR)=12 K的自旋重取向转变,另一个是居里温度为T_(C)=39 K的铁磁−顺磁二级相变。在等温磁化过程中,存在磁场诱导的磁自旋重取向态向正常铁磁态转变的现象,因而在磁熵变(−ΔS_(M))−温度(T)图中,分别在T_(S)和T_(C)附近出现了两个同向的磁熵变峰,且在0~5 T磁场下,T_(SR)和T_(C)温度附近的最大磁熵变可分别达5.3 J/(kg·K)和12.7 J/(kg·K)。由于两种临界温度不同的磁相变会引起合金的制冷温跨增大,进而表现出大的相对制冷能力(RCP);在0~5 T磁场下,Ho_(3)NiSi_(2)合金的制冷温跨和相对制冷能力分别为57.2 K和375.5 J/kg。In this paper,the phase,structure,magnetic transformation and magnetocaloric properties of Ho_(3)NiSi_(2) alloy were studied based on XRD patterns,isothermal magnetization curves and constant magnetic field variable temperature magnetization curves.The results show that there are obvious differences in the content of the second phase Ho_(5)Si_(3) and the atomic occupation of the main phase in the Ho_(3)NiSi_(2) alloy prepared by different methods.There are two magnetic transitions in the Ho_(3)NiSi_(2) alloy at low field.One is spin reorientation transition with T_(SR)=12 K,and the other is ferromagnetic paramagnetic second-order transition with Curie temperature T_(C)=39 K.In the isothermal magnetization process,there is a phenomenon of magnetic field induced magnetic spin reorientation ferromagnetic state transition to normal ferromagnetic state.Therefore,in the magnetic entropy change(−ΔS_(M))-temperature diagram,there are two peaks of magnetic entropy change in the same direction near T_(SR) and T_(C),respectively.Under 0−5 T magnetic field,the maximum magnetic entropy change of Ho_(3)NiSi_(2) alloy near T_(SR) and T_(C) can reach 5.3 J/(kg·K)and 12.7 J/(kg·K),respectively.Due to the contribution of two kinds of phase transformation magnetic entropy at different temperatures,the cooling temperature span of the alloy increases effectively,and then shows a great relative cooling capacity(RCP).The cooling temperature span and relative cooling capacity of Ho_(3)NiSi_(2) alloy are 57.2 K and 375.5 J/kg,respectively.

关 键 词：Ho_(3)NiSi_(2)合金 磁相变 磁热效应 

分 类 号：O482.54[一般工业技术—材料科学与工程]