Stress sensors based on magnetostrictive thin films

Abstract

A remote interrogatable highly sensitive stress sensor based on soft magnetic magnetostrictive amorphous FeCoBSi thin films has been developed. This sensor is very interesting for stress and torque measurements on rotating or hidden objects. It consists of a resonating circuit (LC-tag) with a magnetically sandwiched strip inductor and a thin film capacitor. The resonance frequency of this device is about 500 MHz with quality factors about 8. A figure of merit of 1600 was reached with such devices.