Advanced Magnetic Microwires as Sensing Elements for LC-Resonant-Type Magnetoimpedance Sensors: A Comprehensive Review

In recent years, all modern vehicles and transport means use a vast variety of sensors and transducers. The operation of all medical instruments is also based on sensors and transducers. Industry is also employing more and more transducers for the monitoring and control of production lines. Therefore, the sensing technology has been driven by the increasing needs for enhanced sensitivity, improved stability, high reliability, and lower costs. For this purpose, we have proposed and developed novel two LC resonant-type magnetoimpedance (LCMI) sensor devices utilizing soft magnetic microwires as a sensing element, giving an emphasis on the use of resonance effect from LC-components and the rapid permeability change of the magnetic microwires to significantly improve the sensitivity performance of sensors. This article aims to provide a comprehensive analysis of the design and operation of these devices. After a description of magnetic core materials, circuit designs and fabrication techniques is given, the details of all experimental measurements are presented. The characterizations of constructed LCMI sensor devices are systematically analyzed, and the physical origins of magneto-resonant phenomena, field, and frequency dependences in these LCMI sensor devices are addressed. Influences of processing parameters on the sensing characteristics of LCMI sensors are also discussed. This enables the optimal conditions to fabricate high-performance magnetic sensing devices.