Asymmetrical magneto-impedance effect in twisted amorphous wires for sensitive magnetic sensors

An asymmetrical and sensitive magneto-impedance effect was realized in twisted FeCoSiB and CoSiB amorphous wires magnetized with a dc-biased ac current, in impedance up to about 120%/Oe. The asymmetrical magneto-impedance (AMI) is useful to construct linear field sensors without any dc bias field. Mechanisms of the AMI are also discussed.