Structure and magnetic properties of Sm2(Fe1−<i>x</i>Al<i>x</i>)17N<i>y</i> compounds

Abstract

By means of x-ray phase analysis, it is shown that all the interstitial Sm2(Fe1−xAlx)17Ny nitrides and the parent compounds crystallize in Th2Zn17-type structure for x≤0.4. The lattice constants 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 of Curie temperature Tc . The composition dependence of Tc of the parent compounds exhibits a maximum, whereas Tc of the nitride decreases 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 nitrides and parents decrease monotonously with increasing Al concentration.