The Curie temperature, magnetic moment and magnetovolume effects in Fe-Sc amorphous alloys

A systematic study of the magnetic properties of Fe-Sc amorphous alloys has been carried out for the first time. The samples were prepared by dc high-rate sputtering. The average magnetic moment is larger than that of Fe-Zr and Fe-Ti amorphous alloys. This trend is in conformity with the results obtained by band calculations. The difference in magnitude between calculated and observed magnetic moments in Fe-early transition metals is explained by taking into account the contraction of atomic distance. The thermal expansion anomaly associated with the spontaneous volume magnetostriction ωsis more pronounced with decreasing Sc content and the shrinkage is observed even above the Curie temperature. The Curie temperature exhibits the highest value around 20% Sc. The pressure shift of the Curie temperature is also significantly large, reflecting a large value of ωs. The pressure coefficient of the Curie temperature (1/Tc)(dTc/dP) varies linearly with the Curie temperature, and its sign changes around 20% Sc. The striking thermal expansion anomaly above Tc, and the linear relationship between (1/Tc)(dTc/dP) and Tcimply that the present Fe-Sc amorphous alloys are magnetically inhomogeneous.