Planar Hall bead array counter microchip with NiFe/IrMn bilayers

Abstract

The planar Hall effect (PHE) magnetic bead array countermicrochip integrating 24 of single sensors based on a simple NiFe/IrMn bilayer structure with a patterned size of 3×3 μm2 has been fabricated and characterized. Single PHE sensors exhibit a sensitivity of about 2.5 mΩ/Oe. It was well applied for single Dynabeads® M-280 detection, where one bead can induce a signal change, ΔV∼2.2 mV, under the applied magnetic field of 20 Oe and a sensing current of 2 mA. This type of microchip is promising for quickly detecting and identifying multiple biological agents in the environment.