Signal dependence on magnetic nanoparticles position over a planar Hall effect biosensor

► Disk-shaped Permalloy planar Hall effect sensors have been obtained. ► High field sensitivity has been obtained in a very simple structure. ► Experiments for detection of maghemite nanoparticles have shown good sensitivity. ► Micromagnetic simulations have been performed to explain the experimental data. ► The sensor signal depends on the spatial locations of magnetic nanoparticles.