Studies On Giant Magneto-impedance Effect And Magnetization Properties In NiFeCoP/CuBe Composite Wire

In this paper, we prepared the NiFeCoP/CuBe composite wires by electroless-deposition. Then the giant magneto-impedance effect (GMI) of the NiFeCoP/CuBecomposite wires was studied systemically. The results as follows:1 , The NiFeCoP films are excellently electroless-deposited on CuBe wire and the NiFeCoP/CuBe composite wire is hereby prepared.2, The composition of NiFeCoP film is dependent on the concentrations of Ni²⁺/ Co²⁺ Fe²⁺ pH value and temperature in NiFeCoP electroless-plating bath, which is vital to the GMI effect of the NiFeCoP/CuBe composite wires. The optimal conditions are as follow: [Ni²⁺]/[Co²⁺] = 5.36,[Fe²⁺]=0.05M/L,pH =10-10.2 and temperature is 90℃.And when the CuBe wires were deposited for 1 hour in the bath, the thickness of the ferromagnetic layer is about 5 μm.3, NiFeCoP/CuBe samples are sensitive to annealing temperature. With the increase of the temperature, the magnetic properties are changed.4, The magneto-impedance effect of NiFeCoP/CuBe sample is analyzed at low frequency. In the NiFeCoP/CuBe composite wire, the resistance and the inductive is equal at about 17kHz. So the Magneto-Inductive Effect is obviously contributed to the Magneto-Impedance Effect at low frequency.5, Analyzing the magnetization properties of NiFeCoP/CuBe composite wire. We can get some information of magnetization from the magneto-impedance. The structural difference between ferry-magnetic layer and inductor layer makes the composite wire sensitive to annealing temperature. The heat stress originated from temperature effect raises the resistance of domain, and enlarges the pin effect. All these effects alter the magnetization of ferromagnetic layer. Therefore, the composite wires have various MI at different DC magnetic filed H_DC.