Linearization strategies of spin valve GMR sensor for reversible bipolar magnetic response for wide field range operations

In recent years, magnetoresistance (MR) sensors have gained significant interest due to their miniature size, low power consumption, and high sensitivity, making them an integral part of many industrial and biomedical applications. In non-recording sensing applications, MR sensors must demonstrate high precision, zero hysteresis, high thermal stability, and reliable performance across a wide range of measuring fields; consequently, it is necessary to engineer fabrication strategies. This review article presents various techniques for fabricating magnetic field sensing elements based on spin valve giant magnetoresistance (SV- GMR) technology. Here, emphasis has been given on various approaches to fabricate linear, hysteresis-free, and bipolar sensors in the form of a push-pull Wheatstone bridge configuration. Different linearization strategies, such as high-aspect-ratio resistor fabrication ( ~ 30–50) to leverage the anisotropy field, along with longitudinal biasing (LB) using an ex-situ coil and permanent magnet, and soft pinning the sensing layer through an in-situ adjacent antiferromagnetic (AFM) layer, are explored for tuning linearity, hysteresis and sensitivity. This review article provides comprehensive overview of state-of-the-art strategies for developing reliable SV-GMR magnetic field sensors.