Giant magneto-impedance effect in CoMnSiB amorphous microwires

Abstract

The giant magneto-impedance (GMI) ratio, Δ Z/ Z=[( Z( H)− Z( H max)]/ Z( H max), in a nearly zero magnetostrictive Co 68.5Mn 6.5Si 10B 15 amorphous microwire has been investigated for the frequency range 0.5–10 MHz, driving current amplitude of 0.5–2.5 mA, bias DC magnetic field up to 2400 A/m and under applied tensile stress up to 132 MPa. A maximum relative change in the GMI ratio up to around 130% is observed at a frequency of 10 MHz, magnetic DC field of about 180 A/m, driving current amplitude of 1 mA and under tension of 60 MPa. The tensile stress dependence of the magnetic field, H m, corresponding to the maximum Δ Z/ Z ratio allows to estimate the magnetostriction constant ( λ s≈−2×10 −7) to be in good agreement with λ s values estimated by different methods and in amorphous alloys with similar compositions.