Evolution of magnetic permeability and magneto-impedance effect in composite wires with insulator layer

CuBe/Insulator/NiCoP composite wire was prepared by electroless deposition on an insulated CuBe core with a diameter of 90 μm. The conversion relationship between the magneto-impedance and effective magnetic permeability of the composite wire was derived from an energy conversion model. The evolution of the magnetic permeability and the giant magneto-impedance (GMI) effect were investigated. The results show that a distinct GMI effect can be obtained at relatively low frequency. The largest GMI ratio is 240% at 600 kHz, and the maximal field sensitivity is 34%/Oe.