The effect of nitrogen insertion on the magnetic and structural properties of Sm_(2-x)Gd_xFe_(17) alloys (0 ≤ x ≤ 2)

摘要

The effect of nitrogen insertion on the structural and magnetic properties of Sm_(2-x)Gd_xFe_(17)N_y compounds (x = 0-2) has been investigated. X-ray diffraction patterns at room temperature show that all our synthesized samples are single phase and crystallize in the rhombohedral Th_2Zn_(17)-type structure with very small amount of impurity. Nitrogen insertion leads to a monotonic increase in the unit cell volume, it leads also to an increase in the Curie temperature T_c from 425 K for SmGdFe_(17) to 760 K for SmGdFe_(17)N_3. Moreover, the nitrogen insertion increases the saturated magnetization M_s. M_s increases from 17.9 μ_B/mole for SmGdFe_(17) to 32.7 μ_B/mole for SmGdFe_(17)N_3. X-ray diffraction measurements on magnetically aligned powder samples of Sm_(2-x)Gd_xFe_(17)N_y reveal a change in the easy magnetization direction from planar before nitrogen insertion to the c-axis after nitrogen insertion.