Effect of Direct-Current Bias on the Perpendicular Giant Magneto-Impedance of a Meander-Line Multilayer Structure

While the effect of bias direct currents on longitudinal giant magnetoimpedance (GMI) has been well studied, there have been very few investigations of their effect on perpendicular GMI. We report an experimental investigation of the influence of bias direct currents on perpendicular GMI in meander-line NiFe/Cu/NiFe/Cu/Cr films. The low-field sensitivity and linearity of perpendicular GMI both increased with the use of bias currents for high frequencies (>5 MHz), and the field-dependent linear range of the impedance became wider with increasing frequency. This lays a solid foundation for the development of low-field GMI sensors with high sensitivity and linearity, which are particularly well suited for the detection of weak perpendicular magnetic fields.