Crystallographic and magnetic properties of a new rare-earth iron nitride Nd_(2-x)Sm_xFe_(17)N_y (y～3)

摘要

The effect of nitrogen insertion on the structural and magnetic properties of Nd_(2-x)Sm_xFe_(17) metallic alloys has been investigated. X-ray powder diffraction characterizations show that all the nitrides are single phase and crystallize in the Th_2Zn_(17)-type structure. The lattice parameters of the Nd_(2-x)Sm_xFe_(17)N_y compounds decrease with samarium content. Magnetization studies show that all the samples are ferromagnetic at room temperature. Nitrogen insertion leads to an increase of the Curie temperature T_c. T_c is found to increase from 370 K for NdSmFe_(17) to 760 K for NdSmFe_(17)N_(2.8). It leads also to an increase of the saturation magnetization M_s.M_s(y)-M_s(0)/M_s(0) decreases with increasing samarium content from 58% for x = 0 to 45% for x = 2. X-ray diffraction characterizations on magnetically aligned powder samples of Nd_(2-x)Sm_xFe_(17)N_y reveal a change in the easy magnetization direction from planar for x = 0 to c axis for x = 2.