Enhancement of giant magneto-impedance effect in Ni80Fe20/SiO2/Cu composite wires

Ni80Fe20/SiO2/Cu composite wires of Cu core 60 μm in diameter and coated with layers of SiO2 and Ni80Fe20 were prepared by RF magnetron sputtering. The influences of the insulator layer thickness, the measurement mode and the magnitude of the driving current on the giant magneto-impedance (GMI) effect were investigated. The results showed that there was an optimum thickness of the insulator layer and the driving current can influence the shape of the MI curve. Resonance enhancement of the GMI was found in the new measurement mode. The results are discussed by taking account of the electromagnetic interactions.