Enhanced Giant Magnetoimpedance Properties of Fe-Based Amorphous Ribbons by Coating Soft Magnetic Film

Giant magnetoimpedance (GMI) properties of Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons coated by Fe60Co40 or Fe59Co32P9 film have been investigated. The absolute value of impedance is increased compared to that of the pure Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons by the film coating. The GMI ratio is improved at the high frequency (10 MHz) of the alternating-driven current, while it is reduced at the low-driven frequency (1 MHz), which can be mainly attributed to the enhancement of transverse permeability after deposition of the soft magnetic film with lower electrical conductivity. The linear region in magnetoimpedance profiles is broadened, which is beneficial for sensor application. The result provides a way to improve the GMI properties of Fe-based amorphous ribbons at a low cost.