Magnetisation and magnetovolume effect in amorphous R_0.2Fe_0.8 (R identical to Y, Pr, Nd, Sm, Gd, Tb, Dy and Er) alloys

Magnetisation, thermal expansion and forced volume magnetostriction of amorphous R_0.2Fe_0.8(R identical to Y, Pr, Nd, Sm, Gd, Tb, Dy and Er) alloys have been measured to make clear the contribution of R elements to both the Fe moment m_Fe and the magnetovolume effect. The value of m_Fe in these alloys ranges from 1.6 mu _B to 2.3 mu _B, depending on the R elements. All R_0.2Fe_0.8 alloys show an Invar property. The forced volume magnetostriction at about Curie temperature shows the same R dependence of the mean magnetic moment m. The local environmental effect on the Fe moment in the amorphous state is discussed in comparison with the corresponding crystalline R-Fe compounds.