Asymmetric off-diagonal magnetoimpedance in field-annealed amorphous ribbons: Analysis of bias current effect

The influence of bias current on the asymmetric off-diagonal magnetoimpedance in field-annealed amorphous ribbons is studied. It is assumed that the ribbon consists of an amorphous bulk and two surface hard magnetic crystalline layers appearing after the annealing. The off-diagonal magnetoimpedance is calculated in the framework of the quasi-static approximation. Without the bias current, the asymmetry in the field dependence of the off-diagonal impedance is related to the exchange coupling between the surface layers and amorphous phase. In the presence of the bias current, the asymmetry results from the interaction between the field induced by the bias current and the exchange coupling bias field. It is shown that the bias current affects significantly the field dependence of the off-diagonal impedance.