Very large magnetoimpedance effect in a glass-coated microwire LC-resonator

This paper reports on the high-frequency giant magnetoimpedance (GMI) effect in an LC-resonator built on a glass-coated amorphous Co67Fe3.8Ni1.4B11.5Si14.6Mo1.7 microwire with two cylindrical electrodes at the ends of the microwire. In the investigated frequency range of 100–600 MHz, the GMI effect observed first increases with increasing frequency, reaching a maximum at 146 MHz, and then decreases at higher frequencies. It has been demonstrated that the resonance in a glass-coated microwire LC-resonator occurs at a specific intensity of applied DC magnetic field. More noticeably, extremely large increases of GMI at near resonance frequency are observed. The maximum GMI response due to the resonance of LC components up to 90,000% is found by precise tuning of the frequency around 146.30 MHz. This result is very ideal for developing high-frequency and ultra-sensitive GMI-based magnetic sensor applications. The extreme GMI effect in a constructed LC-resonator originates from both the permeability changes of the microwire and the LC-resonance of the circuit.