NiCo sensing layer for enhanced signals in planar hall effect sensors

Abstract

NiCo alloy materials have been investigaged as a potential sensing layer for planar Hall effect (PHE) sensors in magnetic multilayer structures. In this study, the magnetoresistive performance of the NiCo alloy is compared with that of the NiFe alloy. With an optimum thickness of 10 nm, the increment of the PHE voltage (V max ) for the NiCo-based sensor was approximately 1.5 times larger than that of the NiFe-based sensor. The field sensitivity of both sensor types appeared to be nearly equal. However, the dynamic field range for the NiCo sensor was increased by approximately 40% compared with that of the NiFe sensor. The measuring configuration was optimized in order to obtain higher field sensitivity in the sensor. The field sensitivity was measured to be at a maximum at a 20° angle between the easy axis of the sensor and the applied external field, which was approximately three times higher than that in the perpendicular direction.