Magnetic particles detection by using spin valve sensors and magnetic traps

In this paper, a spin-valve sensor with integrated current lines for concentration and detection of magnetic particles is presented. This device has the advantage of not requiring an external magnetic field source such as permanent magnet to magnetize the particles or to bias the spin-valve sensor. Due to the device design, the magnetic field created by the current lines allows the control of the sensor operating point, to magnetize the particles and also to concentrate the particles in the sensor active area in order to be detected by the spin valve sensor. Detection experiments using FeCrNbB magnetic particles show that the device is capable to detect and quantify the particles in a linear scale over a concentration range of 0.1 to 1 mg/ml.