The influence of current amplitude on asymmetric off-diagonal magnetoimpedance in field-annealed amorphous ribbons

The giant magnetoimpedance (GMI) implies a huge change in the impedance of a magnetic conductor with the variation of an external magnetic field. The field-dependent signal can be measured either as the voltage across the conductor, or as the voltage in the pick-up coil wound around the sample. The latter effect is based on the cross-magnetization process and has been referred to as the off-diagonal magnetoimpedance. Most of the GMI studies have been performed at sufficiently low ac current amplitudes, when the voltage response is proportional to the sample impedance. Recently, a considerable interest has been attracted to nonlinear effects at higher ac current amplitudes. In this case, other harmonics appear in the voltage response, and their field sensitivity turns out to be much higher as compared to the first harmonic sensitivity, which is promising for applications. This paper presents the results of the study of the current amplitude effect on the first and second harmonics in the off-diagonal impedance response in field-annealed Co-based amorphous ribbons.