3∶29型Gd3(Fe1-xCox)29-yCry化合物的成相与结构

通过X射线衍射分析和磁测量研究了Gd-Fe-Co-Cr四元系中对应于化学式Gd₃(Fe,Co,Cr)₂₉且Gd含量为一定值的截面内富Fe,Co区的相关系,重点探索了高Co含量3∶29型化合物合成的可能性,研究了3∶29型Gd₃(Fe_1-xCo_x)_29-yCr_y化合物的结构与磁性.研究结果表明,获得3∶29型单相Gd₃(Fe_1-xCo_x)_29-yCr_y化合物的范围为:y=5,0≤x≤0.7;y=5.5,0.7≤x≤0.8和y=6,0.8≤x≤0.9.基于对Gd₃(Fe_1-xCo_x)_29-yCr_y化合物成相条件的研究,成功地合成了纯Co基Gd₃Co_29-yCr_y化合物,其固溶范围为6.5≤y≤7.3.3∶29型单相Gd₃(Fe_1-xCo_x)_29-yCr_y化合物的晶体结构都属于单斜晶系,Nd₃(Fe,Ti)₂₉型结构,空间群为A2m.得到3∶29型单相Gd₃(Fe_1-xCo_x)_29-yCr_y化合物的固溶极限即Co含量的极大值与稳定元素Cr含量有关.Co原子的含量越高,所需稳定元素Cr的含量越大.值得注意的是,用Co原子替代Fe原子会导致Gd₃(Fe_1-xCo_x)_29-yCr_y化合物磁晶各向异性的显著改变.当x≥0.4时,化合物的磁晶各向异性从易面型转变为易轴型 关键词： 3(Fe_1-xCo_x)_29-yCr_y化合物')" href="#">Gd₃(Fe_1-xCo_x)_29-yCr_y化合物 相关系和相结构 X射线衍射 磁晶各向异性

FORMATION AND STRUCTURE OF 3

Based on a study of the phase relation in the Fe- and Co-rich region of the equi-gadolinium content section with the Gd content corresponding to the chemical formula Gd₃(Fe,Co,Cr)₂₉ in the Gd-Fe-Co-Cr quaternary system, formation, structure and magnetic properties of the 3∶29-type Gd₃(Fe_1-xCo_x)_29-yCr_y compounds have been investigated. It has been found that the composition range of formation of the single phase Gd₃(Fe_1-xCo_x)_29-yCr_y Compounds is 0≤x≤0.7 for y=5.0, 0.7≤x≤0.8 for y=5.5, and 0.8≤x≤1.0 for y=6.0. A pure Co-based Gd₃Co_29-xCr_x compound series have been synthesized. The solubility limit of the Cr atoms in the Gd₃Co_29-xCr_x compounds was found to be from x=6.5 to x=7.3. The results indicate that all the synthesized Gd₃(Fe_1-xCo_x)_29-yCr_y compounds crystallize in Nd₃(Fe,Ti)₂₉ type structure of the monoclinic system and the space group A2/m.The solubility limit of Co atoms in the Gd₃(Fe_1-xCo_x)_29-yCr_y compounds increases with increasing the stabilizing element Cr. It is noteworthy that substitution of Co for Fe leads to a remarkable change of the magnetocrystalline anisotropy of the Gd₃(Fe_1-xCo_x)_29-yCr_y compounds. When x≥0.4 the anisotropy changes from the easy plane type to the uniaxial type, which is important for permanent magnet application.