Structure and magnetic properties of Er3(Fe, Co, M)29 compounds (M=Cr, V, Ti, Mn, Ga, Nb)
Er3(Fe, Co, M)29化合物(M=Cr, V, Ti, Mn, Ga, Nb)的结构与磁性

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.