アモルファスワイヤのパルス励磁 MI 効果と FM 無線方式 CMOS IC 形磁界センサ

抄録

The figure of merit (FOM) of the magneto-impedance (MI) effect in amorphous wires is defined as (| ∂ Z / ∂ Hex| / Z₀) · f _cutoff. The magnitude of the FOM was found to be almost the same at two operating points on the MI characteristic curve in pulse-magnetized amorphous wires in the domain-wall-displacement-dominant range and the magnetization-rotation-dominant range. The magnitude of the FOM was increased in a twisted amorphous wire by increasing the efficiency of the magnetization rotation for the wire pulse current.
A frequency-modulation-(FM)-type wireless magnetic sensor with low power consumption was devised, utilizing the magnetization-rotation-dominant MI effect in a zero-magnetostrictive amorphous wire combined with two kinds of CMOS IC multivibrators. The wireless MI sensor has been successfully used as an automobile torque sensor.