Thermal-expansion and inverse-magnetic-susceptibility anomalies in amorphous Y-Fe alloys

A large thermal expansion anomaly has been observed in amorphous ${\mathrm{Y}}_{7.5}$ ${\mathrm{Fe}}_{92.5}$ and ${\mathrm{Y}}_{16}$ ${\mathrm{Fe}}_{84}$ alloys over a wide temperature range from the spin glass to the paramagnetic state. This anomaly fades away around 450 K, implying that the magnetic excitation to small amplitudes of local moments is saturated above this temperature. The inverse-magnetic susceptibility influenced by this excitation becomes convex upwards up to around 450 K and varies linearly above this temperature, obeying a new Curie-Weiss law.