Exchange-biased planar Hall effect sensor optimized for biosensor applications

Christian D. Damsgaard, Susana C. Freitas, Paulo P. Freitas, Mikkel F. Hansen
2008 Journal of Applied Physics  
This article presents experimental investigations of exchange-biased Permalloy planar Hall effect sensor crosses with a fixed active area of w ϫ w =40ϫ 40 m 2 and Permalloy thicknesses of t = 20, 30, and 50 nm. It is shown that a single domain model describes the system well and that the thicker film will have a higher signal as well as a lower noise. It is estimated that the signal-to-noise ratio for bead detection increases by a factor 2.1 when t is increased from 20 to 50 nm and hence a
more » ... r t is beneficial for biosensor applications. This is exemplified with calculations on M-280 Dynabeads®.
doi:10.1063/1.2830008 fatcat:pjsqbyq4pbg3xf7e5ajfwnrbyq