Linear Spin-Valve Bridge Sensor for Weak Magnetic Fields

Spin-valves are utilized in a variety of devices including magnetic sensors and biological detection systems. The sensing devices are characterized by three parameters: the sensing field range, sensitivity and linearity. The linear spin-valve sensing element is configured as a Wheatstone bridge. Two kinds Wheatstone bridge were investigated. First, the bridge consist of two sensing resistors and two fixed value resistors, which has no hysteresis and linearity error is less than 0.15% in the operation range of -6 Oe to 6 Oe, shows a sensitivity of 0.78 mV/VmiddotOe. Second, the linear bridge sensor consisting of four sensing resistors shows a sensitivity of 1.54 mV/VmiddotOe in the operation range of -6 Oe to 6 Oe and a linearity error less than 0.3%