STRUCTURE AND MAGNETIC-PROPERTIES OF SM2(FE1-XALX)17NY COMPOUNDS

By means of x-ray phase analysis, it is shown that all the interstitia l Sm2(Fe1-xAlx)17Ny nitrides and the parent compounds crystallize in T h2Zn17-type structure for x less-than-or-equal-to 0.4. The lattice con stants of the parent compounds increase linearly with Al concentration . The introduction of nitrogen leads to a further increase in lattice constants, but the amplitude of the increase decreases with increasing Al concentration. The introduction of nitrogen leads to an increase o f Curie temperature T(c). The composition dependence of T(c) of the pa rent compounds exhibits a maximum, whereas T(c) of the nitride decreas es monotonously with increasing Al concentration from 750 K for x=0 to 313 K for x=0.4. The mean magnetic moments of iron ions in both nitri des and parents decrease monotonously with increasing Al concentration .