Planar Hall Voltage Properties of Ta/NiFe/Ta/NiFe/Ta Multilayer for Biosensor Applications

Abstract

Recently, magnetic nanoparticles and planar Hall resistance (PHR) devices used in biomolecule diagnosis and biological applications have attracted considerable attention as biosensors. The voltage properties of a planar Hall device with a Ta/NiFe/Ta/NiFe/Ta multilayer that was prepared in a cross-shaped pattern at a width of 0.5 mm using a shadow mask, were investigated. The sensitive planar Hall voltage (SPHV) obtained from the planar Hall voltage (PHV) curves of a Ta(5 nm)/NiFe(6 nm)/Ta(t = 2-8 nm)/NiFe(6 nm)/Ta(5 nm) multilayered sample was a few mV/Oe in the fine magnetic field region of the external magnetic field of ± 1.0 Oe. In particular, the thickness of Ta(t = 8 nm), the PHR ratio, magnetic sensitivity, and SPHV improved significantly by as much as 36.4 %, 28 %/Oe, and 1.6 mV/Oe, respectively. These results can be used in the development of a PHR biosensor with a high sensitivity for the detection of nanoparticle-antibody binding, even in a simple structure formed only out of a ferromagnetic NiFe layer.