Magnetic Field Dependence of Magnetic Bead Signals

The magnetic field dependence of magnetic bead signals were measured by planner Hall resistance (PER) and self-field (SF) methods by using PHR sensor. The bead signals of Delta PHR/PHRo, measured with PHR method and ASF/SF, measured with SF method showed high hysteresis and low stability at H < H-eff, which was due to the hysteresis of the magnetic materials of NiFe/Cu/MnIr used in PHR sensor. While, the bead signals measured at H > H-eff showed very stable and Delta SF/SFo showed maximum 14 times improved signal properties than Delta PHR/PHRo. The stable bead signals measured by SF method at H > 2H(eff) can be used to the biosensor.