Er3(Fe,Co, M)29化合物(M=Cr,V, Ti,Mn, Ga,Nb)的结构与磁性

合成了Er_３Fe_29-x-yCo_xM_y化合物(M=Cr, V, Ti, Mn, Ga, Nb )并用x射线衍射和磁测量等手段研究了它们的结构和磁性. 发现Fe基Er_３(Fe,M)_２９化合物结晶成哑铃对Fe-Fe无序替代的Th₂Ni₁₇型结构(P6₃/mmc空间群)而不能形成Nd₃(Fe,Ti)_２９型结构，因此其化学式也可以用Er_2－n(Fe,M)_17+2n (n=0.2)表示. 当Er_３Fe₂₉化合物中部分Fe原子被M原子所取代时，其居里温度均有一定程度的提高. 所有Er_３(Fe,M)_２９化合物在室温均为易面型各向异性. 当Er_３(Fe,M)_２９ (M=Cr, V)中的部分Fe原子被Co原子取代且Co原子数与Fe原子数达到一定比值时，得到一个单斜结构的新相. 磁测量表明Er_３Fe_19.5Co₆V_3.5在室温可能为单轴各向异性，在162K出现自旋重取向，其各向异性由易轴型变为易面型. 在5K下于难磁化方向磁化时观察到一个一级磁化过程(FOMP). 关键词： 稀土金属间化合物 晶体结构 磁晶各向异性

Structure and magnetic properties of Er3(Fe, Co, M)29 compounds (M=Cr, V, Ti, Mn, Ga, Nb)

A series of Er_3(Fe, Co, M)_ 29 (M=Cr, V, Ti, Mn, Ga, Nb) compounds has been synthesized and their structure and magnetic properties have been investigates by means of x-ray diffraction and magnetic measurements. It is found that the Fe-based Er_3(Fe,M)_ 29 compounds crystallize in the Th_2Ni_ 17-type structure with disordered substitution of the dumbbell Fe-Fe, instead of Nd_3(Fe,Ti)_ 29-type structure, so its chemical formula can also be expressed as Er_ 2-n(Fe,M)_ 17 2n (n=0.2). Substitution of M for Fe in the Er_3Fe_ 29 compound leads to an increase in the Curie temperature. With the substitution of Co for Fe in the Er_3(Fe,M)_ 29 (M=Cr, V) compounds, a new phase was found which crystallizes in monoclinic symmetry. The anisotropy of the Er_3Fe_ 19.5Co_6V_ 3.5 compound at room temperature is of easy-axis type and a spin reorientation transition from the easy-axis type to the easy-plane type anisotropy occurs when temperature decreases to 162K. A first order magnetization process (FOMP) was observed in the HMD magnetization curve of Er_3Fe_ 19.5Co_6V_ 3.5 at 5K, the critical field of the FOMP was derived to be 3.8T.