Effect of seed layer on the sensitivity of exchange biased planar Hall sensor

We investigate systematically the effects of seed layer thickness on the sensitivity of exchange biased planar Hall sensors. The sensors consist of Ni80Fe20 (ts)/Fe50Mn50 (20 nm)/Ni80Fe20 (20 nm) trilayers deposited on silicon substrates by sputtering, with ts varied from 0 nm to 50 nm. The sensors are linear near zero-field as a result of the pinning field from the Fe50Mn50 layer. We observed that the sensitivity and range of linearity of the sensors are strongly dependent on the Ni80Fe20 seed layer thickness. The sensitivity of the sensors were also calculated by taking into account the shunting effects of the various metal layers, and the values obtained agree well with the experimental values.