Linearization and Field Detectivity in Magnetic Tunnel Junction Sensors Connected in Series Incorporating 16 nm-Thick NiFe Free Layers

In this work, arrays of MgO-based magnetic tunnel junction elements
$(5\times 20\ \mu{\rm m}^{2})$
connected in series are studied for sensor applications. Linearization is obtained by combining shape anisotropy with a longitudinal hard bias field set by CoCrPt permanent magnets integrated on the sides of the array. We show that this architecture has the drawback of a large footprint in the chip, but is largely compensated by the weak bias voltage dependence and huge electric robustness, when comparing with individual magnetic tunnel junctions.