Magnetic and structural properties of Nd₂Fe_17-xM_x (M = Cu, Cr, V, Nb, and Zr) compounds

We report the structural and magnetic properties of Nd₂Fe_17-xM_x (M = Cu, Cr, V, Nb, and Zr), where x = 0, 0.5, 1, 1.5, 2, 2.5, 3, and 4. X-ray diffraction shows that these compounds form the rhombohedral Th₂Zn₁₇ structure with a small amount of α-Fe for some of the samples with small x values. For some of these compounds the rhombohedral structure cannot be formed at large values of x. X-ray diffraction on magnetically aligned samples show that these samples have in-plane anisotropy. The unit cell volume is found to increase with x for M = V, Nb, and Zr and decrease with x for M = Cu and Cr. The saturation magnetization decreases with x for all M atoms both at 25 and 300 K with the decrease ranging from 5 to 15% for x = 1. The Curie temperature increases with x for small values of x with the increase ranging from 10 to 20% for x = 1.