’’Critical’’ neutron scattering in amorphous HoFe2 and GdFe2

Small angle neutron scattering measurements were made on amorphous HoFe2 and GdFe2. For HoFe2 the intensity for T≳Tc (195 K) is Lorentzian in form and can be analyzed for an inverse correlation length κ1 which remains finite at Tc. Below Tc a giant anomalous magnetic component appears, which follows a q−2.4 dependence and can be analyzed in terms of magnetic inhomogeneities of dimension comparable to κ1−1 at Tc. Limited measurements at fixed q indicate the absence of this component in GdFe2, suggesting an origin based on local crystalline field effects.Small angle neutron scattering measurements were made on amorphous HoFe2 and GdFe2. For HoFe2 the intensity for T≳Tc (195 K) is Lorentzian in form and can be analyzed for an inverse correlation length κ1 which remains finite at Tc. Below Tc a giant anomalous magnetic component appears, which follows a q−2.4 dependence and can be analyzed in terms of magnetic inhomogeneities of dimension comparable to κ1−1 at Tc. Limited measurements at fixed q indicate the absence of this component in GdFe2, suggesting an origin based on local crystalline field effects.