This article presents experimental investigations of exchange-biased Permalloy planar Hall effect sensor crosses with a fixed active area of w x w = 40 x 40 mu 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 higher t is beneficial for biosensor applications. This is exemplified with calculations on M-280 Dynabeads (R).
Bibliographical noteCopyright (2008) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Damsgaard, C. D., Freitas, S. C., Freitas, P. P., & Hansen, M. F. (2008). Exchange-biased planar Hall effect sensor optimized for biosensor applications. Journal of Applied Physics, 103(7), 07A302. https://doi.org/10.1063/1.2830008