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Planar Hall effect biosensors
Planar Hall effect based biosensors were fabricated for the T.U.Dennmark. a graduate student (Louise Esjing) spent one year at INWESC MN fabricating the devices based on a weakly AF biased Permalloy (20nm thick) layers. The AF bias is used to create a monodomain state and to linearize the sensor response. The planar Hall sensors have lower low frequency noise when compared with spin valve or MTJ sensors, but also show less field sensitivity (MR ratio of about 2%, compared with 10% for SVs, and 40 % to 200% in MTJs). A second visitor from TUD came for two weeks to INESC in 2006, for the fabrication of a second series of devices.
