Reserch On The Spin Valve Sensor Based On Giant Magnetoresistance Effect

With the continuous development of the Internet of Things(IOT) technology, the giant magnetoresistance(GMR) sensor as an important component of a non-access-type probe currents in demanding automatic protection features and more advanced intelligent control technology has a broad applications. Based on the spin valve effect sensor with small size, high sensitivity, excellent thermal stability and good linearity etc, making it much attention of researchers. To achieve high stability and consistency of thin film layers of the spin valve sensing unit, a sensing unit of the best plating done, but because of the requirements of the sensing element linear process, making a spin valve sensor unit plating not easy to achieve. Therefore, this paper mainly focus on the difficulties, starting from the spin-valve unit structure, to achieve the spin-valve sensor linearization plating unit once completed, the sensor process design and performance research conducted on this basis.Papers with a plating layer to achieve freedom and spin-valve unit pinned layer perpendicular magnetic moment, thus achieving linear spin-valve sensor unit as the core research, first proposed in Si/Cu/IrMn/NiFe/IrMn/Cu/NiFe multilayer film 90-degree offset from the composite structure of the free layer, by optimizing the thickness of each film, the sputtering gas pressure, power, and found a composite free layer and the pinned layer perpendicular to each other once the preparation good conditions, on this basis, the preparation of the composite free layer/barrier layer/pinned layer/pinned layer of the spin valve overall structure, tested, good linearity performance. Secondly, the free layer and the spacer layer thickness of Cu layer bias point of the spin valve, and artificial antiferromagnetic pinned layer instead of the conventional composite structure by weakening the coupling of the pinned layer magnetic moment of the free layer, reducing the non-zero bias spin valve sensors meet the requirements of the application. Finally, lithography design and processing of the Wheatstone bridge spin valve magnetoresistive sensors, flow through the spin valve sensor chip samples, to achieve for 63-103 Oe linear magnetic field measurements. Measurement results show that the sensor has good linearity and 0.45mV/Oe sensitivity.