Giant magnetoimpedance effect in a glass-coated microwire LC-resonator for high-frequency sensitive magnetic sensor applications

This letter reports on the high-frequency giant magnetoimpedance (GMI) effect in a LC-resonator built on a glass-coated Co83.2B3.3Si5.9Mn7.6 microwire with two cylindrical electrodes at the ends of the microwire. In the investigated frequency range of 100-1000 MHz, the shape of GMI curves varies drastically as the frequency increases. It has been demonstrated that the resonance in a glass-coated microwire LC-resonator occurs at a specific intensity of the applied dc magnetic field. The sudden changes of the phase angle as large as 180 degrees evidence the occurrence of the resonance. The GMI features in a LC-resonator originate from both the permeability changes of the microwire and the LC-resonance of the circuit. More interestingly, extremely large increases of GMI in the vicinity region of the resonant frequency (similar to 890 MHz) are also observed. The maximum GMI response up to 10,000% has been found at the frequency of 889.41 MHz. This result is very beneficial for developing a new family of high-frequency and ultra-sensitive GMI-based magnetic sensor applications. (c) 2006 Elsevier B.V. All rights reserved.