AC-driven AMR and GMR magnetoresistors

摘要

anisotropic (AMR) and Giant (GMR) Magnetoresistive sensors are attactive for industrial applications, as they are more sensitive and stable than Hall sensors. Their performance may be improved by AC excitation: flipping for AMR and AC biasing for GMR. AC excitation lowers the hysteresis and reduces the offset and in some cases also decreases sensor noise. The sensitivity to perpendicular fields is reduced in case of AMR sensors. Ac-driven magnetoresistors are competitive to miniature fluxgate sensors and they are suitable for precise applications such as compass.