By using a model for giant magnetoresistance (GMR) hysteresis and a model for Barkhausen noise, a magnetic hysteresis model is used to map the effects of magnetic hysteresis on GMR and on accompanying magnetic noise in a GMR magnetic field sensor. Two magnetic noise sources potentially exist in the field sensor: (1) the GMR multilayer material and (2) permalloy field concentrators. The GMR material typically shows a coercivity at Hc≅1 kA/m, much larger than Hc=0.012 kA/m of permalloy. Because permalloy has a very large maximum permeability, it is a much larger magnetic noise source than the GMR material, and would greatly affect sensor operation if operated near H=0. By operating with a bias field well above 1 kA/m, one can operate away from both noise sources. Because the increasing and decreasing arms of the magnetic hysteresis tail of the GMR material are each approximately proportional to |H|1/2 over a large field range, the model shows that increasing and decreasing portions of the GMR vs H hysteresi...
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