Magnetic Field Sensor Based on Giant Magnetoimpedance

Giant magnetoimpedance (GMI) effect has been studied in amorphous magnetic microwires where internal mechanical stresses derived from fabrication process influence strongly in its magnetic properties. Glass covered amorphous microwire of composition (Fe₆Co₉₄)_72.5Si_12.5B₁₅ have been characterized in low magnetic DC field, for AC currents from 75 to 500 muA and frequencies from 1 to 14MHz. In all measurements a double peak response, characteristic of Co-rich samples with circular anisotropy, was obtained and GMI of 99% was reached. The design of a high sensitive magnetic field sensor has been made obtaining a linear response in plusmn130 A/m range with two microwires with the appropriate bias magnetic field.