Improving the sensitivity of asymmetric magnetoimpedance in exchange biased NiFe/IrMn multilayers

We investigate the asymmetric magnetoimpedance effect in exchange biased NiFe/IrMn multilayers and explore the possibility of tailoring the linear region of the curves around zero magnetic field by playing with the thickness of the ferromagnetic layers, probe current frequency, and the orientation between external magnetic field and exchange bias field direction. We quantify the sensitivity by calculating the |dZ/dH|H=0 in a wide range of frequencies. The highest sensitivity is observed for the thicker multilayer, reaching ∼160mΩ/Oe at ∼2.0GHz. The results place exchange biased magnetoimpedance multilayers as attractive candidates for the development of auto-biased linear magnetic field sensors.