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 ?� m2 has been fabricated and characterized. Single PHE sensors exhibit a sensitivity of about 2.5 m/Oe. It was well applied for single Dynabeads?? M-280 detection, where one bead can induce a signal change, ??V�?�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. ?? 2008 American Institute of Physics.
