In situ detection method for obtaining permeability of Fe-based amorphous alloys: ac resistance measurement for Fe84Nb7B9

In this letter, we propose an in situ detection method for obtaining permeability of soft magnetic Fe-based amorphous alloys. The temperature dependence of ac resistance was measured at different frequencies during heat treatment of Fe84Nb7B9 amorphous alloys. A significant increase in the ac (∼1000 kHz) resistance appears at around 920 K during the heating process, which arises from the skin effect caused by a marked increase in sample permeability. This skin effect diminishes when the sample is heated to approximately 1100 K, which corresponds to the decrease in its permeability. Consequently, we note that the ac resistance measurement is useful for quick in situ assessment to achieve the soft magnetic property of an Fe-based amorphous alloy