Effect of glass removal on the GMI effect of Co_(71.8)Fe_(4.9)Nb_(0.8)Si_(7.5)B_(15) amorphous glass-covered wires

摘要

During the past several years, giant magneto-impedance effect (GMI) in amorphous wires has generated growing interest in the science community because of their applications in sensors. The giant magneto-impedance effect in Co_(71.8)Fe_(4.9)Nb_(0.8)Si_(7.5)B_(15) amorphous glass-covered wires (AGCW) consists of strong changes in the high frequency impedance with a small DC magnetic field. When f = 1 MHz, there is no GMI effect due to the fact that the magnetic penetration depth is higher than their radius. As the frequency increases, the GMI effect becomes important in both the glass-covered wire and the wire after glass removal. Field dependence of the impedance has a similar behaviour to the AGCW ones, when a tensile stress is applied to the wire without glass cover.