Soft magnetic properties in Fe-based nanocrystalline alloy

Amorphous Fe84Zr7B6Cu1Al2 and Fe81B11Nb7CU1 alloys were annealed at 723 K and 823 K for one hour to achieve good soft magnetic properties such as large magnetoimpedance ratio (MIR) and incremental permeability ratio (PR), etc. The MIR and PR of the samples were measured from 100 kHz to 10 MHz in a cryogenic chamber with temperatures from 10 K up to 300 K. The values of coercive force reveal that the optimum temperature for better soft magnetic properties is 723 K in both samples. The maximum value of MI ratio increases drastically in the Fe81B11Nb7CU1 alloy annealed at 723 K and 823 K indicating that the sample is softened by nanocrystallization. The maximum PR values of Fe84Zr7B6Cu1Al2 alloy measured below 1 MHz show drastic increment at above 150 K clue to thermal activation of magnetic domains.