Effect of “overlapping” voltage contacts in planar hall transducers

A mathematical model is derived to compute the output of a planar Hall tranducer (PHT) with overlapping voltage contacts at arbitrary positions and of arbitrary sizes. The model is based on the finite difference representation of the integral equation J…n ds = 0. In order to verify the model, the output of five PHTs with varying overlap sizes is measured in homogeneous and inhomogeneous fields. The computed results prove to be in good agreement with the experimental ones. The model is used to predict the effect of overlapping contacts on the output and resolution for several transducer configurations. The results are given in a number of diagrams. It is shown that a PHT with lower contacts (at the medium side) can be advantageous with respect to a biased (barber-pole) magnetoresistive (MR) head having the same size.