THE CRYSTALLIZATION TEMPERATURE, ELECTRICAL-RESISTIVITY AND MAGNETIC-PROPERTIES OF CO-Y AMORPHOUS-ALLOYS

Several kinds of Co-Y amorphous alloys have been prepared by high-rate dc sputtering. Thermal analysis, electrical resistivity and thermomagnetization measurements have been used to obtain the crystallization temperature. From systematic study of the dilute concentration range, the magnetic properties of pure amorphous Co are deduced. The thermomagnetization and electrical resistivity curves exhibit a drastic change near the crystallization temperature as determined from DSC curves. The concentration dependence of the crystallization temperature shows a remarkable increase at low concentrations of Y and reaches about 1170 K at 10. 5% Y, corresponding to Co//1//7Y//2. The Curie temperature in the amorphous state is higher than in the crystalline state, and the extrapolated value of pure amorphous Co is higher than that of pure crystalline Co, resulting in a small high-field susceptibility and a large spin-wave stiffness constant for pure amorphous Co.