Mo-containing Finemet alloys: microstructure and magnetic properties

The influence of the partial substitution of Fe by Mo (up to 5 at.%) on the microstructure and magnetic properties of Finemet-type alloys has been studied. The change with Mo content of the peak temperature of the first exotherm is fit by a linear function, with an increase of about 15 K/at.% Mo. However, for the second exotherm no monotonic function was found to fit the change with Mo content. From the temperature dependence of the low-field (∼20 mT) magnetization, a linear decrease of the Curie temperature of the initial amorphous phase of about 25 K/at.% Mo is found. Room-temperature quasistatic hysteresis loops have been measured for samples annealed at different temperatures, showing that the minimum coercivity is not affected by the Mo content of the precursor alloy.