Thermal Expansion of Sputtered Amorphous (Hf, Ta)Fe2 Alloys

Thermal expansion of vapor-quenched itinerant-electron ferromagnetic amorphous Hf 1- x Ta x Fe 2 alloys for 0≦ x ≦1 has been measured from 20 to 300 K. A positive anomaly has been clearly observed for x =0 at about and below the Curie temperature. Its magnitude decreases with increasing x and almost disappears for x >0.7. These results have been discussed on the basis of the effect of spontaneous volume magnetostriction due to the ferromagnetic moment.