AMR current sensor with monolithically integrated bias magnets

Abstract:
NdFeB micromagnets are integrated by the PowderMEMS(r) microfabrication technique into the substrate of commercial AMR magnetic field sensors to replace discrete ferrite bias magnets. The micromagnet design is customized to provide a homogeneous in-plane bias field of 3 kA/m. Experimental results confirm the precise local tailoring of the bias field and the functioning of the integrated AMR element in commercial current sensors. The demonstrated fabrication approach is scalable, enables further miniaturization and allows for lower production costs due to reduced package size and omission of discrete assembly. The concept can also be applied to other combinations of microdevices and magnetic materials.