Nonlinear magnetization reversal of Co-based amorphous microwires induced by an ac current

The magnetization reversal of ferromagnetic Co-based amorphous microwires carrying ac current is studied. The frequency spectra of the voltage V-phi induced in the pick-up coil wound around the microwires were analysed and were found to depend on the ac current amplitude Io and external longitudinal de magnetic field H-e. The even harmonics are shown to dominate in the frequency spectra of V-phi if the ac current amplitude exceeds some threshold value, which strongly depends on H-e. A high sensitivity of the even harmonic amplitudes to the longitudinal de field is demonstrated. The experimental data are described in terms of the Faraday law and the quasi-static Stoner-Wohlfarth model. The results obtained may be of importance for the design of weak magnetic field sensors.