Magnetic properties of Sm2Fe17Ny with Al substituted for Fe

By means of X-ray diffraction analysis, it is shown for x < 0.4 that all the interstitial Sm-2(Fe1-xAlx)(17)N-y nitrides and the parent compounds crystallize with Th2Zn(17)-type structure. The lattice constants of the parent compounds increase linearly with Al concentration. The introduction of nitrogen atoms leads to a further increase in the lattice constants, but the increase becomes smaller with increasing Al concentration; this can be related to the fact that the nitrogen content introduced into the parent compounds decreases nearly linearly with increasing Al concentration. The dependence on composition of T-c of the parent compounds exhibits a maximum, whereas T-c of the nitrides decreases monotonically with Al content from 750 K for x=0 to 313 K for x=0.4. The introduction of nitrogen leads to enhancement of the average magnetic moment of Fe in Sm2Fe17, whereas the substitution of Al for Fe leads to a decrease in the average magnetic moment of Fe in both the nitrides and the parent compounds. The anisotropy field B-a of nitrides is almost independent of the Al concentration for x less than or equal to 0.3, then decreases very fast and becomes zero at about x = 0.4.