Wheatstone Bridge Magnetic Sensor Based on LocalManipulation of Exchange Bias System by Current Heating in MgO Magnetic Tunnel Junctions

摘要

@@ MgO based magnetic tunnel junction (MTJs) is one of promising candidates for magnetic sensor due to its intrinsic advantages over GMR, AMR and Hall sensors, like high signal level, small size, low cost, and low power consumption. In the industrial applications, in order to compensate for temperature drifts in different environment, which give rise to a change in resistance, balanced bridge circuits are required to remove the DC offset. However, the incorporation of MgO based magnetic tunnel junctions (MTJ) in a full Wheatstone bridge configuration raises a number of problems due to the simultaneous requirement of high annealing temperature to crystallize the CoFeB (Ta>300°C), and the setting of the two different and symmetric orientations. Early GMR devices used a