The magnetic moment at the yttrium site in Y-Fe compounds: pressure dependence of the magnetisation and hyperfine field

The pressure dependence of the magnetisation of Y 2 Fe 17 , Y 6 Fe 23 and YFe 2 at 4.2 K has been deduced from forced volume magnetostriction measurements in fields up to 12 T. The pressure dependence of the 89 Y hyperfine field in the above compounds and YFe 3 has been measured using NMR. The results are consistent with a model in which a moment of approximately=-0.4 mu B exists at the Y site of all four compounds as found in computer calculations for YFe 2 .