Fe替代Mn对Mn2Dy化合物的结构和磁相关性能的影响

Structure and Magnetic Properties of (Mn1-xFex)2Dy Compounds with Fe Dopping

采用真空氩弧熔炼的方法制备了（Mn1-xFex）2Dy（x=0-1.0）系列样品,在800℃下进行热处理10 h,利用X射线衍射仪（XRD）、综合物性测量系统（PPMS）、电阻应变片法等测试方法系统研究了不同Fe替代量对Mn2Dy化合物的结构演变、磁性能和磁致伸缩性能的影响。研究结果表明,Mn2Dy化合物具有典型的Mg Cu2（C15型）面心立方（fcc）晶体结构,随着Fe替代量x的增加,（Mn1-xFex）2Dy化合物的晶胞体积和晶胞参数a,b,c逐渐减小,但始终保持fcc晶体结构不变;Mn2Dy化合物为反铁磁体,当Fe替代量x〉0.5时,该化合物开始由反铁磁性向铁磁性转变,饱和磁化强度（Ms）可在-6.0-80.0 Am2·kg^-1之间调控;反铁磁Mn2Dy几乎不显示磁致伸缩性能,随着Fe替代量的增加,磁致伸缩系数（λ）逐步提高且灵敏度越来越高,当x=0.9时在72 kA·m^-1外场下λ最高可以达到350×10^-6。机制探讨表明,铁磁性的Fe元素替代Mn后改变了Mn2Dy化合物的磁晶各向异性与磁性,从而影响了磁致伸缩性能。

The （Mn1-xFex）2Dy （ x = 0 - 1.0） samples were prepared by vacuum argon art： melting method, then annealed at 800 ℃ for 10 h, and the effects of dilterent Fe substitutions on the structural evolution, magnetic properties and magnetostriction performance of Mn2Dy compounds were investigated by X-ray diffraction （XRD） , physical property measurement system （PPMS） anti resistance strain gage method. The results showed that the crystal structure of Mn2Dy eompound was MgCu2 （C15 type） , which was face-centered cubic （fee） phase. The unit cell volumes and lattice parameter a, b, c of （Mn1-xFex）2Dy compounds decreased gradually with the increase of x, but crystal structure kept the fcc structure. Mn2Dy compound was antiferromagnets, nevertheless, the magnetic type of （Mn1-xFex）2Dycompounds began to transform front antiferromagnetism to ferromagnetism when x 〉 0. 5, and the saturation magnetization （M） could be controlled between - 6.0 - 80.0 Am^2·kg^-1 . The antiferromagnetie Mn2Dy showed almost no magnetostriction performance. With the increase of Fe-substitution, the magnetostriction coefficient （A） increased gradually anti the sensitivity was improved. When x =0.9, the maximum of a could reach 350 × 10^-6 at 72 kA·^m-1 external magnetic field. The mechanism analysis showed that the substitution of Fe changed the magnetocrystalline anisotropy and magnetic properties of Mn, Dy compound, and then affeeted the magnetostriction performance.