Amorphous wire and CMOS IC-based sensitive micromagnetic sensors utilizing magnetoimpedance (MI) and stress-impedance (SI) effects

Abstract

New sensitive quick-response and low-power-consumption micromagnetic sensors, namely, the magnetoimpedance (MI) sensor utilizing the MI effect in zero-magnetostrictive amorphous wires and the stress-impedance (SI) sensor utilizing the SI effect in negative-magnetostrictive amorphous wires, are presented. The field detection resolution of the CMOS IC-type MI sensor is about I /spl mu/Oe for ac fields and 100 /spl mu/Oe for a dc field with the full scale of /spl plusmn/3 Oe using a 2- or 0.5-mm-long amorphous wire with 30- or 15-/spl mu/m diameter as a sensor head. The possible response speed is about 1 MHz, and the power consumption is about 10 mW. The magnetoimpedance integrated circuit (MIIC sensor was developed in 2002 by the Aichi Steel Company, Japan, for mass production. The stress detection resolution of the SI sensor is about 0.1 Gal in acceleration Sensing, which is suitable for detection of microdisplacement in the medical field. More than 100 themes are proposed for application of MI and SI sensors.