NdNi_(4-x)Co_(x)Cu系列化合物的磁性和磁热效应  

Magnetic Properties and Magnetocaloric Effects in NdNi_(4-x)Co_(x)Cu Compounds

作　　者：乌日嘎 特古斯[1,2] 欧志强 Wuriga;Tegus O;OU Zhi-qiang(College of Physics and Electronic Information,Inner Mongolia Normal University,Hohhot 010022,China;Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials,Hohhot 010022,China)

机构地区：[1]内蒙古师范大学物理与电子信息学院,内蒙古呼和浩特010022 [2]内蒙古自治区功能材料物理与化学重点实验室,内蒙古呼和浩特010022

出　　处：《内蒙古师范大学学报（自然科学版）》2022年第2期121-126,共6页Journal of Inner Mongolia Normal University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(11864031)。

摘　　要：对NdNi_(4-x)Co_(x)Cu系列化合物的制备工艺、晶体结构和磁性进行研究。用电弧熔炼和热处理法制备NdNi_(4-x)Co_(x)Cu(x=0,1.0,1.5,1.7,1.9,2.0,2.1,2.3,3.0,4.0)系列化合物样品,对X射线衍射数据精修后分析发现,该系列化合物为单相材料,晶体结构为CaCu_(5)型六角结构,空间群为P6/mmm,并给出精修图谱和精修后的XRD衍射图。磁性测量分析表明,该系列化合物发生自旋重取向现象和由铁磁到顺磁的转变,居里温度随着Co含量的增加而升高,该系列化合物的居里温度具有可调性。利用热力学麦克斯韦关系,从系列等温磁化曲线确定了样品的等温磁熵变随温度和磁场变化的关系。在外场强度3 T的条件下,当x<2时,其最大等温磁熵变值随着Co含量的增加而降低,当x>2时最大等温磁熵变值随Co含量的增加再次降低。外场强度1 T条件下,NdNi_(2)Co_(2)Cu样品的相对制冷功率(RCP)为128 J/kg。The preparation procedure,crystal structure and magnetic properties of NdNi_(4-x)Co_(x)Cu series compounds were investigated in the paper.The NdNi_(4-x)Co_(x)Cu(x=0,1.0,1.5,1.7,1.9,2.0,2.1,2.3,3.0,4.0)series of compound samples were prepared by arc melting and heat treatment and X⁃ray diffraction data of the compounds were refined and analyzed.The results found that the series of compounds were single-phase materials,CaCu_(5) type hexagonal crystal structure,with space group P6/mmm and the refined XRD diffraction pattern was also presented in the paper.The magnetic measurement and analysis showed that the series of compounds underwent a spin reorientation and a transition from ferromagnetic to paramagnetic.The Curie temperature of the series of compounds increased with the increase of Co content and was adjustable.In the light of the Maxwell relation in thermodynamics,the relationship between the isothermal magnetic entropy change of the samples and temperature and magnetic field change was determined from the isothermal magnetization curves.Under field change of 0-3 T,for x<2,the maximum isothermal magnetic entropy change decreased with the increase of Co content;for x=1,the maximum isothermal magnetic entropy change was 1.4 J/kgK.When x>2,the maximum isothermal magnetic entropy change decreased also with the increase of Co content.The relative cooling power(RCP)of the NdNi_(2)Co_(2)Cu sample for a field change of 1 T was 128 J/kg.

关 键 词：居里温度 自旋重取向 磁熵变 磁热效应 

分 类 号：O482.54[一般工业技术—材料科学与工程]