Hall sensor response to an inhomogeneous magnetic field

The response of a Hall-effect sensor to a spatially dependent magnetic field is of importance for many applications such as magnetic microscopy and nondestructive testing. Using the analytical expression of the response of a Greek cross Hall sensor response to an ideal field dot published a few years ago, we have calculated its sensitivity and its full width at half maximum for the field produced by a magnetic dipole and by two coplanar lines. The experimental results are in good agreement with theory. They show that the spatial resolution is roughly equal to the dimension of the central part of the Greek cross and that a flux-meter approximation is not appropriate for modeling such Hall-effect sensors for very close field sources.