The future of magnetic sensors

Abstract The operation of magnetic-field sensors is based on many different physical principles ranging from induction to magneto-optical effects. This in turn leads to a vast range of possible magnetic sensor types. What will finally decide the commercial viability of a particular magnetic sensor is its performance as well as its compatibility with miniaturization and microelectronic circuits. The magnetic sensors with the most potential for future applications include: Hall devices, magnetoresistors, inductive coils and fluxgates. The Hall device, while very compatible with microelectronics, suffers from a limited sensitivity in silicon, a high level oof 1 F noise and a relatively large offset. Ferromagnetic magnetoresistors generally have a high sensitivity at a low field; associated problems are the flipping effect and hysteresis. Inductive coils find many applications in proximity and distance sensors, but the miniaturization of coils is difficult. The fluxgate is a highly sensitive magnetic sensor. In principle, it could be integrated, but the main challenges are the three-dimensional structure of the coils and the low magnetic permeability of integrated ferromagnetic cores. The performance of sensors can be considerably improved by incorporating them into a system and using synergistic relationships such as feedback and compensation. The future of magnetic sensor microsystems looks bright with many promising application areas.

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