MAGNETO-IMPEDANCE (MI) SENSORS EMPLOYING CURRENT CONFINEMENT AND EXCHANGE BIAS LAYER(S) FOR INCREASED SENSITIVITY

摘要

Magneto-impedance (MI) sensors employing current confinement and exchange bias layer(s) for increased MI sensitivity are disclosed. MI sensors may be used as biosensors to detect biological materials. The sensing by the MI devices is based on a giant magneto-impedance (GMI) effect, which is very sensitive to a magnetic field. The GMI effect is a change in impedance of a magnetic material resulting from a change in skin depth of the magnetic material as a function of an external direct current (DC) magnetic field applied to the magnetic material and an alternating current (AC) current flowing through the magnetic material (or adjacent conductive materials). Thus, this change in impedance resulting from a magnetic stray field generated by magnetic nanoparticles can be detected in lower concentrations and measured to determine the amount of magnetic nanoparticles present, and thus the target analyte of interest.